mirror of
https://github.com/LCTT/TranslateProject.git
synced 2025-03-21 02:10:11 +08:00
struggling
commit
6da1f2b83e
@ -2,8 +2,6 @@
|
||||
================================================================================
|
||||
|
||||
|
||||
图片来源 : opensource.com
|
||||
|
||||
经过了一整天的Opensource.com[社区版主][1]年会，最后一项日程提了上来，内容只有“特邀嘉宾：待定”几个字。作为[Opensource.com][3]的项目负责人和社区管理员，[Jason Hibbets][2]起身解释道，“因为这个嘉宾有可能无法到场，因此我不想提前说是谁。在几个月前我问他何时有空过来，他给了我两个时间点，我选了其中一个。今天是这三周中Jim唯一能来的一天”。（译者注：Jim是指下文中提到的Jim Whitehurst，即红帽公司总裁兼首席执行官）
|
||||
|
||||
这句话在版主们（Moderators）中引起一阵轰动，他们从世界各地赶来参加此次的[拥抱开源大会(All Things Open Conference)][4]。版主们纷纷往前挪动椅子，仔细聆听。
|
||||
@ -14,7 +12,7 @@
|
||||
|
||||
“大家好！”，这个家伙开口了。他没穿正装，只是衬衫和休闲裤。
|
||||
|
||||
这时会场中第二高个子的人，红帽全球意识部门(Global Awareness)的高级主管[Jeff Mackanic][5]，告诉他大部分社区版本今天都在场，然后让每个人开始作简单的自我介绍。
|
||||
这时会场中第二高个子的人，红帽全球意识部门(Global Awareness)的高级主管[Jeff Mackanic][5]，告诉他大部分社区版主今天都在场，然后让每个人开始作简单的自我介绍。
|
||||
|
||||
“我叫[Jen Wike Huger][6]，负责Opensource.com的内容管理，很高兴见到大家。”
|
||||
|
||||
@ -22,13 +20,13 @@
|
||||
|
||||
“我叫[Robin][9]，从2013年开始参与版主项目。我在OSDC做了一些事情，工作是在[City of the Hague][10]维护[网站][11]。”
|
||||
|
||||
“我叫[Marcus Hanwell][12]，来自英格兰，在[Kitware][13]工作。同时，我是FOSS科学软件的技术总监，和国家实验室在[Titan][14] Z和[Gpu programming][15]方面合作。我主要使用[Gentoo][16]和[KDE][17]。最后，我很激动能加入FOSS和开源科学。”
|
||||
“我叫[Marcus Hanwell][12]，来自英格兰，在[Kitware][13]工作。同时，我是FOSS science software的技术总监，和国家实验室在[Titan][14] Z和[Gpu programming][15]方面合作。我主要使用[Gentoo][16]和[KDE][17]。最后，我很激动能参与到FOSS和开源科学。”
|
||||
|
||||
“我叫[Phil Shapiro][18]，是华盛顿的一个小图书馆28个Linux工作站的管理员。我视各位为我的同事。非常高兴能一起交流分享，贡献力量。我主要关注FOSS和自豪感的关系，以及FOSS如何提升自豪感。”
|
||||
“我叫[Phil Shapiro][18]，是华盛顿的一个小图书馆的28个Linux工作站的管理员。我视各位为我的同事。非常高兴能一起交流分享，贡献力量。我主要关注FOSS和自豪感的关系，以及FOSS如何提升自豪感。”
|
||||
|
||||
“我叫[Joshua Holm][19]。我大多数时间都在关注系统更新，以及帮助人们在网上找工作。”
|
||||
|
||||
“我叫[Mel Chernoff][20]，在红帽工作，和[Jason Hibbets]和[Mark Bohannon]一起主要关注政府渠道方面。”
|
||||
“我叫[Mel Chernoff][20]，在红帽工作，和[Jason Hibbets][22]和[Mark Bohannon][23]一起主要关注[政府][21]渠道方面。”
|
||||
|
||||
“我叫[Scott Nesbitt][24]，写过很多东西，使用FOSS很久了。我是个普通人，不是系统管理员，也不是程序员，只希望能更加高效工作。我帮助人们在商业和生活中使用FOSS。”
|
||||
|
||||
@ -38,41 +36,41 @@
|
||||
|
||||
“你在[新FOSS Minor][30]教书？！”，Jim说道，“很酷！”
|
||||
|
||||
“我叫[Jason Baker][31]。我是红慢的一个云专家，主要做[OpenStack][32]方面的工作。”
|
||||
“我叫[Jason Baker][31]。我是红帽的一个云专家，主要做[OpenStack][32]方面的工作。”
|
||||
|
||||
“我叫[Mark Bohannan][33]，是红帽全球开放协议的一员，在华盛顿外工作。和Mel一样，我花了相当多时间写作，也从法律和政府部门中找合作者。我做了一个很好的小册子来讨论正在发生在政府中的积极变化。”
|
||||
|
||||
“我叫[Jason Hibbets][34]，我组织了这次会议。”
|
||||
“我叫[Jason Hibbets][34]，我组织了这次讨论。”
|
||||
|
||||
会场中一片笑声。
|
||||
|
||||
“我也组织了这片讨论，可以这么说，”这个棕红色头发笑容灿烂的家伙说道。笑声持续一会逐渐平息。
|
||||
“我也组织了这个讨论，可以这么说，”这个棕红色头发笑容灿烂的家伙说道。笑声持续一会逐渐平息。
|
||||
|
||||
我当时在他左边，时不时从转录空隙中抬头看一眼，然后从眼神中注意到微笑背后暗示的那个自2008年1月起开始领导公司的人，红帽的CEO[Jim Whitehurst][35]。
|
||||
我当时在他左边，时不时从记录的间隙中抬头看一眼，我注意到淡淡微笑背后的那个令人瞩目的人，是自2008年1月起开始领导红帽公司的CEO [Jim Whitehurst][35]。
|
||||
|
||||
“我有世界上最好的工作，”稍稍向后靠、叉腿抱头，Whitehurst开始了演讲。“我开始领导红帽，在世界各地旅行到处看看情况。在这里的七年中，FOSS和广泛的开源创新所发生的美好的事情是开源已经脱离了条条框框。我现在认为，IT正处在FOSS之前所在的位置。我们可以预见FOSS从一个替代走向创新驱动力。”用户也看到了这一点。他们用FOSS并不是因为它便宜，而是因为它能提供和创新的解决方案。这也十一个全球现象。比如，我刚才还在印度，然后发现那里的用户拥抱开源的两个理由：一个是创新，另一个是那里的市场有些特殊，需要完全的控制。
|
||||
“我有世界上最好的工作，”稍稍向后靠、叉腿抱头，Whitehurst开始了演讲。“我开始领导红帽，在世界各地旅行到处看看情况。在这里的七年中，FOSS和广泛的开源创新所发生的最美好的事情是开源已经脱离了条条框框。我现在认为，信息技术正处在FOSS之前所在的位置。我们可以预见FOSS从一个替代品走向创新驱动力。我们的用户也看到了这一点。他们用FOSS并不是因为它便宜，而是因为它能带来可控和创新的解决方案。这也是个全球现象。比如，我刚才还在印度，然后发现那里的用户拥抱开源的两个理由：一个是创新，另一个是那里的市场有些特殊，需要完全的可控。”
|
||||
|
||||
“[孟买证券交易所][36]想得到源代码并加以控制，五年前这在证券交易领域闻所未闻。那时FOSS正在重复发明轮子。今天看来，FOSS正在做几乎所有的结合了大数据的事物。几乎所有的新框架，语言和方法论，包括流动（尽管不包括设备），都首先发生在开源世界。”
|
||||
“[孟买证券交易所][36]想得到源代码并加以控制，五年前这种事情在证券交易领域就没有听说过。那时FOSS正在重复发明轮子。今天看来，实际上大数据的每件事情都出现在FOSS领域。几乎所有的新框架，语言和方法论，包括移动通讯（尽管不包括设备），都首先发生在开源世界。”
|
||||
|
||||
“这是因为用户数量已经达到了相当的规模。这不只是红帽遇到的情况，[Google][37]，[Amazon][38]，[Facebook][39]等也出现这样的情况。他们想解决自己的问题，用开源的方式。忘掉协议吧，开源绝不仅如此。我们建立了一个交通工具，一套规则，例如[Hadoop][40]，[Cassandra][41]和其他工具。事实上，开源驱动创新。例如，Hadoop在厂商们意识的规模带来的问题。他们实际上有足够的资和资源金来解决自己的问题。”开源是许多领域的默认技术方案。这在一个更加注重内容的世界中更是如此，例如[3D打印][42]和其他使用信息内容的物理产品。”
|
||||
“这是因为用户数量已经达到了相当的规模。这不只是红帽遇到的情况，[Google][37]，[Amazon][38]，[Facebook][39]等也出现这样的情况。他们想解决自己的问题，用开源的方式。忘掉许可协议吧，开源绝不仅如此。我们建立了一个交通工具，一套规则，例如[Hadoop][40]，[Cassandra][41]和其他工具。事实上，开源驱动创新。例如，Hadoop是在厂商们意识到规模带来的问题时的一个解决方案。他们实际上有足够的资金和资源来解决自己的问题。开源是许多领域的默认技术方案。这在一个更加注重内容的世界中更是如此，例如[3D打印][42]和其他使用信息内容的实体产品。”
|
||||
|
||||
“源代码的开源确实很酷，但开源不应当仅限于此。在各行各业不同领域开源仍有可以用武之地。我们要问下自己：‘开源能够为教育，政府，法律带来什么？其它的呢？其它的领域如何能学习我们？’”
|
||||
|
||||
“还有内容的问题。内容在现在是免费的，当然我们可以投资更多的免费内容，不过我们也需要商业模式围绕的内容。这是我们更应该关注的。如果你相信开放的创新能带来更好，那么我们需要更多的商业模式。”
|
||||
“还有内容的问题。内容在现在是免费的，当然我们可以投资更多的免费内容，不过我们也需要商业模式围绕的内容。这是我们更应该关注的。如果你相信开放的创新更好，那么我们需要更多的商业模式。”
|
||||
|
||||
“教育让我担心其相比与‘社区’它更关注‘内容’。例如，无论我走到哪里，大学校长们都会说，‘等等，难道教育将会免费？！’对于下游来说FOSS免费很棒，但别忘了上游很强大。免费课程很棒，但我们同样需要社区来不断迭代和完善。这是很多人都在做的事情，Opensource.com是一个提供交流的社区。问题不是‘我们如何控制内容’，也不是‘如何建立和分发内容’，而是要确保它处在不断的完善当中，而且能给其他领域提供有价值的参考。”
|
||||
“教育让我担心，其相比与‘社区’它更关注‘内容’。例如，无论我走到哪里，大学的校长们都会说，‘等等，难道教育将会免费？！’对于下游来说FOSS免费很棒，但别忘了上游很强大。免费课程很棒，但我们同样需要社区来不断迭代和完善。这是很多人都在做的事情，Opensource.com是一个提供交流的社区。问题不是‘我们如何控制内容’，也不是‘如何建立和分发内容’，而是要确保它处在不断的完善当中，而且能给其他领域提供有价值的参考。”
|
||||
|
||||
“改变世界的潜力是无穷无尽的，我们已经取得了很棒的进步。”六年前我们痴迷于制定宣言，我们说‘我们是领导者’。我们用错词了，因为那潜在意味着控制。积极的参与者们同样也不能很好理解……[Máirín Duffy][43]提出了[催化剂][44]这个词。然后我们组成了红帽，不断地促进行动，指引方向。”
|
||||
|
||||
“Opensource.com也是其他领域的催化剂，而这正是它的本义所在，我希望你们也这样认为。当时的内容质量和现在比起来都令人难以置信。你可以看到每季度它都在进步。谢谢你们的时间！谢谢成为了催化剂！这是一个让世界变得更好的机会。我想听听你们的看法。”
|
||||
“Opensource.com也是其他领域的催化剂，而这正是它的本义所在，我希望你们也这样认为。当时的内容质量和现在比起来都令人难以置信。你可以看到每季度它都在进步。谢谢你们付出的时间！谢谢成为了催化剂！这是一个让世界变得更好的机会。我想听听你们的看法。”
|
||||
|
||||
我瞥了一下桌子，发现几个人眼中带泪。
|
||||
|
||||
然后Whitehurst又回顾了大会的开放教育议题。“极端一点看，如果你有一门[Ulysses][45]的公开课。在这里你能和一群人一起合作体验课堂。这样就和代码块一样的：大家一起努力，代码随着时间不断改进。”
|
||||
|
||||
在这一点上，我有发言权。当谈论其FOSS和学术团体之间的差异，向基础和可能的不调和这些词语都跳了出来。
|
||||
在这一点上，我有发言权。当谈论其FOSS和学术团体之间的差异，像“基础”和“可能不调和”这些词语都跳了出来。
|
||||
|
||||
**Remy**: “倒退带来死亡。如果你在论文或者发布的代码中烦了一个错误，有可能带来十分严重的后果。学校一直都是避免失败寻求正确答案的地方。复制意味着抄袭。轮子在一遍遍地教条地被发明。FOSS你能快速失败，但在学术界，你只能带来无效的结果。”
|
||||
**Remy**: “倒退带来死亡。如果你在论文或者发布的代码中犯了一个错误，有可能带来十分严重的后果。学校一直都是避免失败寻求正确答案的地方。复制意味着抄袭。轮子在一遍遍地教条地被发明。FOSS让你能快速失败，但在学术界，你只能带来无效的结果。”
|
||||
|
||||
**Nicole**: “学术界有太多自我的家伙，你们需要一个发布经理。”
|
||||
|
||||
@ -80,20 +78,21 @@
|
||||
|
||||
**Luis**: “团队和分享应该优先考虑，红帽可以多向它们强调这一点。”
|
||||
|
||||
**Jim**: “还有公司在其中扮演积极角色吗？”
|
||||
**Jim**: “还有公司在其中扮演积极角色了吗？”
|
||||
|
||||
[Phil Shapiro][46]: “我对FOSS的临界点感兴趣。联邦没有改用[LibreOffice][47]把我逼疯了。我们没有在软件上花税款，也不应当在字处理软件或者微软的Office上浪费税钱。”
|
||||
[Phil Shapiro][46]: “我对FOSS的临界点感兴趣。Fed没有改用[LibreOffice][47]把我逼疯了。我们没有在软件上花税款，也不应当在字处理软件或者微软的Office上浪费税钱。”
|
||||
|
||||
**Jim**: “我们经常提倡这一点。我们能做更多吗？这是个问题。首先，我们在我们的产品涉足的地方取得了进步。我们在政府中有坚实的专营权。我们比私有公司平均话费更多。银行和电信业都和政府挨着。我们在欧洲做的更好，我认为在那工作又更低的税。下一代计算就像‘终结者’，我们到处取得了进步，但仍然需要忧患意识。”
|
||||
**Jim**: “我们经常提倡这一点。我们能做更多吗？这是个问题。首先，我们在我们的产品涉足的地方取得了进步。我们在政府中有坚实的专营权。我们比私有公司平均花费更多。银行和电信业都和政府挨着。我们在欧洲做的更好，我认为在那工作有更低的税。下一代计算就像‘终结者’，我们到处取得了进步，但仍然需要忧患意识。”
|
||||
|
||||
突然，门开了。Jim转身向门口站着的执行助理点头。他要去参加下一场会了。他并拢双腿，站着向前微倾。然后，他再次向每个人的工作和奉献表示感谢，微笑着出了门……留给我们更多的激励。
|
||||
|
||||
突然，门开了。Jim转身向门口站着的执行助理点头。他要去参加下一场会了。他并拢双腿，站着向前微倾。然后，他再次向每个人的工作和奉献表示感谢，微笑着除了门……留给我们更多的激励。
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: https://opensource.com/business/14/12/jim-whitehurst-inspiration-open-source
|
||||
|
||||
作者：[Remy][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
译者：[fyh](https://github.com/fyh)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
Linux 日志基础
|
||||
================================================================================
|
||||
首先，我们将描述有关 Linux 日志是什么，到哪儿去找它们以及它们是如何创建的基础知识。如果你已经知道这些，请随意跳至下一节。
|
||||
首先，我们将描述有关 Linux 日志是什么，到哪儿去找它们，以及它们是如何创建的基础知识。如果你已经知道这些，请随意跳至下一节。
|
||||
|
||||
### Linux 系统日志 ###
|
||||
|
||||
@ -10,71 +10,69 @@ Linux 日志基础
|
||||
|
||||
一些最为重要的 Linux 系统日志包括：
|
||||
|
||||
- `/var/log/syslog` 或 `/var/log/messages` 存储所有的全局系统活动数据，包括开机信息。基于 Debian 的系统如 Ubuntu 在 `/var/log/syslog` 目录中存储它们，而基于 RedHat 的系统如 RHEL 或 CentOS 则在 `/var/log/messages` 中存储它们。
|
||||
- `/var/log/syslog` 或 `/var/log/messages` 存储所有的全局系统活动数据，包括开机信息。基于 Debian 的系统如 Ubuntu 在 `/var/log/syslog` 中存储它们，而基于 RedHat 的系统如 RHEL 或 CentOS 则在 `/var/log/messages` 中存储它们。
|
||||
- `/var/log/auth.log` 或 `/var/log/secure` 存储来自可插拔认证模块(PAM)的日志，包括成功的登录，失败的登录尝试和认证方式。Ubuntu 和 Debian 在 `/var/log/auth.log` 中存储认证信息，而 RedHat 和 CentOS 则在 `/var/log/secure` 中存储该信息。
|
||||
- `/var/log/kern` 存储内核错误和警告数据，这对于排除与自定义内核相关的故障尤为实用。
|
||||
- `/var/log/kern` 存储内核的错误和警告数据，这对于排除与定制内核相关的故障尤为实用。
|
||||
- `/var/log/cron` 存储有关 cron 作业的信息。使用这个数据来确保你的 cron 作业正成功地运行着。
|
||||
|
||||
Digital Ocean 有一个完整的关于这些文件及 rsyslog 如何在常见的发行版本如 RedHat 和 CentOS 中创建它们的 [教程][1] 。
|
||||
Digital Ocean 有一个关于这些文件的完整[教程][1]，介绍了 rsyslog 如何在常见的发行版本如 RedHat 和 CentOS 中创建它们。
|
||||
|
||||
应用程序也会在这个目录中写入日志文件。例如像 Apache，Nginx，MySQL 等常见的服务器程序可以在这个目录中写入日志文件。其中一些日志文件由应用程序自己创建，其他的则通过 syslog (具体见下文)来创建。
|
||||
|
||||
### 什么是 Syslog？ ###
|
||||
|
||||
Linux 系统日志文件是如何创建的呢？答案是通过 syslog 守护程序，它在 syslog
|
||||
套接字 `/dev/log` 上监听日志信息，然后将它们写入适当的日志文件中。
|
||||
Linux 系统日志文件是如何创建的呢？答案是通过 syslog 守护程序，它在 syslog 套接字 `/dev/log` 上监听日志信息，然后将它们写入适当的日志文件中。
|
||||
|
||||
单词“syslog” 是一个重载的条目，并经常被用来简称如下的几个名称之一：
|
||||
单词“syslog” 代表几个意思，并经常被用来简称如下的几个名称之一：
|
||||
|
||||
1. **Syslog 守护进程** — 一个用来接收，处理和发送 syslog 信息的程序。它可以[远程发送 syslog][2] 到一个集中式的服务器或写入一个本地文件。常见的例子包括 rsyslogd 和 syslog-ng。在这种使用方式中，人们常说 "发送到 syslog."
|
||||
1. **Syslog 协议** — 一个指定日志如何通过网络来传送的传输协议和一个针对 syslog 信息(具体见下文) 的数据格式的定义。它在 [RFC-5424][3] 中被正式定义。对于文本日志，标准的端口是 514，对于加密日志，端口是 6514。在这种使用方式中，人们常说"通过 syslog 传送."
|
||||
1. **Syslog 信息** — syslog 格式的日志信息或事件,它包括一个带有几个标准域的文件头。在这种使用方式中，人们常说"发送 syslog."
|
||||
1. **Syslog 守护进程** — 一个用来接收、处理和发送 syslog 信息的程序。它可以[远程发送 syslog][2] 到一个集中式的服务器或写入到一个本地文件。常见的例子包括 rsyslogd 和 syslog-ng。在这种使用方式中，人们常说“发送到 syslog”。
|
||||
1. **Syslog 协议** — 一个指定日志如何通过网络来传送的传输协议和一个针对 syslog 信息(具体见下文) 的数据格式的定义。它在 [RFC-5424][3] 中被正式定义。对于文本日志，标准的端口是 514，对于加密日志，端口是 6514。在这种使用方式中，人们常说“通过 syslog 传送”。
|
||||
1. **Syslog 信息** — syslog 格式的日志信息或事件，它包括一个带有几个标准字段的消息头。在这种使用方式中，人们常说“发送 syslog”。
|
||||
|
||||
Syslog 信息或事件包括一个带有几个标准域的 header ,使得分析和路由更方便。它们包括时间戳，应用程序的名称，在系统中信息来源的分类或位置，以及事件的优先级。
|
||||
Syslog 信息或事件包括一个带有几个标准字段的消息头，可以使分析和路由更方便。它们包括时间戳、应用程序的名称、在系统中信息来源的分类或位置、以及事件的优先级。
|
||||
|
||||
下面展示的是一个包含 syslog header 的日志信息，它来自于 sshd 守护进程，它控制着到该系统的远程登录，这个信息描述的是一次失败的登录尝试：
|
||||
下面展示的是一个包含 syslog 消息头的日志信息，它来自于控制着到该系统的远程登录的 sshd 守护进程，这个信息描述的是一次失败的登录尝试：
|
||||
|
||||
<34>1 2003-10-11T22:14:15.003Z server1.com sshd - - pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=10.0.2.2
|
||||
|
||||
### Syslog 格式和域 ###
|
||||
### Syslog 格式和字段 ###
|
||||
|
||||
每条 syslog 信息包含一个带有域的 header，这些域是结构化的数据，使得分析和路由事件更加容易。下面是我们使用的用来产生上面的 syslog 例子的格式，你可以将每个值匹配到一个特定的域的名称上。
|
||||
每条 syslog 信息包含一个带有字段的信息头，这些字段是结构化的数据，使得分析和路由事件更加容易。下面是我们使用的用来产生上面的 syslog 例子的格式，你可以将每个值匹配到一个特定的字段的名称上。
|
||||
|
||||
<%pri%>%protocol-version% %timestamp:::date-rfc3339% %HOSTNAME% %app-name% %procid% %msgid% %msg%n
|
||||
|
||||
下面，你将看到一些在查找或排错时最常使用的 syslog 域：
|
||||
下面，你将看到一些在查找或排错时最常使用的 syslog 字段：
|
||||
|
||||
#### 时间戳 ####
|
||||
|
||||
[时间戳][4] (上面的例子为 2003-10-11T22:14:15.003Z) 暗示了在系统中发送该信息的时间和日期。这个时间在另一系统上接收该信息时可能会有所不同。上面例子中的时间戳可以分解为：
|
||||
|
||||
- **2003-10-11** 年，月，日.
|
||||
- **T** 为时间戳的必需元素，它将日期和时间分离开.
|
||||
- **22:14:15.003** 是 24 小时制的时间，包括进入下一秒的毫秒数(**003**).
|
||||
- **Z** 是一个可选元素，指的是 UTC 时间，除了 Z，这个例子还可以包括一个偏移量，例如 -08:00，这意味着时间从 UTC 偏移 8 小时，即 PST 时间.
|
||||
- **2003-10-11** 年，月，日。
|
||||
- **T** 为时间戳的必需元素，它将日期和时间分隔开。
|
||||
- **22:14:15.003** 是 24 小时制的时间，包括进入下一秒的毫秒数(**003**)。
|
||||
- **Z** 是一个可选元素，指的是 UTC 时间，除了 Z，这个例子还可以包括一个偏移量，例如 -08:00，这意味着时间从 UTC 偏移 8 小时，即 PST 时间。
|
||||
|
||||
#### 主机名 ####
|
||||
|
||||
[主机名][5] 域(在上面的例子中对应 server1.com) 指的是主机的名称或发送信息的系统.
|
||||
[主机名][5] 字段(在上面的例子中对应 server1.com) 指的是主机的名称或发送信息的系统.
|
||||
|
||||
#### 应用名 ####
|
||||
|
||||
[应用名][6] 域(在上面的例子中对应 sshd:auth) 指的是发送信息的程序的名称.
|
||||
[应用名][6] 字段(在上面的例子中对应 sshd:auth) 指的是发送信息的程序的名称.
|
||||
|
||||
#### 优先级 ####
|
||||
|
||||
优先级域或缩写为 [pri][7] (在上面的例子中对应 <34>) 告诉我们这个事件有多紧急或多严峻。它由两个数字域组成：设备域和紧急性域。紧急性域从代表 debug 类事件的数字 7 一直到代表紧急事件的数字 0 。设备域描述了哪个进程创建了该事件。它从代表内核信息的数字 0 到代表本地应用使用的 23 。
|
||||
优先级字段或缩写为 [pri][7] (在上面的例子中对应 <34>) 告诉我们这个事件有多紧急或多严峻。它由两个数字字段组成：设备字段和紧急性字段。紧急性字段从代表 debug 类事件的数字 7 一直到代表紧急事件的数字 0 。设备字段描述了哪个进程创建了该事件。它从代表内核信息的数字 0 到代表本地应用使用的 23 。
|
||||
|
||||
Pri 有两种输出方式。第一种是以一个单独的数字表示，可以这样计算：先用设备字段的值乘以 8，再加上紧急性字段的值：(设备字段)(8) + (紧急性字段)。第二种是 pri 文本，将以“设备字段.紧急性字段” 的字符串格式输出。后一种格式更方便阅读和搜索，但占据更多的存储空间。
|
||||
|
||||
Pri 有两种输出方式。第一种是以一个单独的数字表示，可以这样计算：先用设备域的值乘以 8，再加上紧急性域的值：(设备域)(8) + (紧急性域)。第二种是 pri 文本，将以“设备域.紧急性域” 的字符串格式输出。后一种格式更方便阅读和搜索，但占据更多的存储空间。
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.loggly.com/ultimate-guide/logging/linux-logging-basics/
|
||||
|
||||
作者：[Jason Skowronski][a1]
|
||||
作者：[Amy Echeverri][a2]
|
||||
作者：[Sadequl Hussain][a3]
|
||||
作者：[Jason Skowronski][a1]，[Amy Echeverri][a2]，[Sadequl Hussain][a3]
|
||||
译者：[FSSlc](https://github.com/FSSlc)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
@ -1,15 +1,15 @@
|
||||
Linux问答 -- 如何在Linux上安装Git
|
||||
Linux有问必答：如何在Linux上安装Git
|
||||
================================================================================
|
||||
|
||||
> **问题:** 我尝试从一个Git公共仓库克隆项目，但出现了这样的错误提示：“git: command not found”。 请问我该如何安装Git？ [注明一下是哪个Linux发行版]?
|
||||
> **问题:** 我尝试从一个Git公共仓库克隆项目，但出现了这样的错误提示：“git: command not found”。 请问我该如何在某某发行版上安装Git？
|
||||
|
||||
Git是一个流行的并且开源的版本控制系统（VCS），最初是为Linux环境开发的。跟CVS或者SVN这些版本控制系统不同的是，Git的版本控制被认为是“分布式的”，某种意义上，git的本地工作目录可以作为一个功能完善的仓库来使用，它具备完整的历史记录和版本追踪能力。在这种工作模型之下，各个协作者将内容提交到他们的本地仓库中（与之相对的会直接提交到核心仓库），如果有必要，再有选择性地推送到核心仓库。这就为Git这个版本管理系统带来了大型协作系统所必须的可扩展能力和冗余能力。
|
||||
Git是一个流行的开源版本控制系统（VCS），最初是为Linux环境开发的。跟CVS或者SVN这些版本控制系统不同的是，Git的版本控制被认为是“分布式的”，某种意义上，git的本地工作目录可以作为一个功能完善的仓库来使用，它具备完整的历史记录和版本追踪能力。在这种工作模型之下，各个协作者将内容提交到他们的本地仓库中（与之相对的会总是提交到核心仓库），如果有必要，再有选择性地推送到核心仓库。这就为Git这个版本管理系统带来了大型协作系统所必须的可扩展能力和冗余能力。
|
||||
|
||||
|
||||
|
||||
### 使用包管理器安装Git ###
|
||||
|
||||
Git已经被所有的主力Linux发行版所支持。所以安装它最简单的方法就是使用各个Linux发行版的包管理器。
|
||||
Git已经被所有的主流Linux发行版所支持。所以安装它最简单的方法就是使用各个Linux发行版的包管理器。
|
||||
|
||||
**Debian, Ubuntu, 或 Linux Mint**
|
||||
|
||||
@ -18,6 +18,8 @@ Git已经被所有的主力Linux发行版所支持。所以安装它最简单的
|
||||
**Fedora, CentOS 或 RHEL**
|
||||
|
||||
$ sudo yum install git
|
||||
或
|
||||
$ sudo dnf install git
|
||||
|
||||
**Arch Linux**
|
||||
|
||||
@ -33,7 +35,7 @@ Git已经被所有的主力Linux发行版所支持。所以安装它最简单的
|
||||
|
||||
### 从源码安装Git ###
|
||||
|
||||
如果由于某些原因，你希望从源码安装Git，安装如下介绍操作。
|
||||
如果由于某些原因，你希望从源码安装Git，按照如下介绍操作。
|
||||
|
||||
**安装依赖包**
|
||||
|
||||
@ -65,7 +67,7 @@ via: http://ask.xmodulo.com/install-git-linux.html
|
||||
|
||||
作者：[Dan Nanni][a]
|
||||
译者：[mr-ping](https://github.com/mr-ping)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
61
published/20150810 For Linux, Supercomputers R Us.md
Normal file
61
published/20150810 For Linux, Supercomputers R Us.md
Normal file
@ -0,0 +1,61 @@
|
||||
有了 Linux，你就可以搭建自己的超级计算机
|
||||
================================================================================
|
||||
|
||||
> 几乎所有超级计算机上运行的系统都是 Linux，其中包括那些由树莓派（Raspberry Pi）板卡和 PlayStation 3游戏机组成的计算机。
|
||||
|
||||
|
||||
|
||||
*题图来源：By Michel Ngilen,[ CC BY 2.0 ], via Wikimedia Commons*
|
||||
|
||||
超级计算机是一种严肃的工具，做的都是高大上的计算。它们往往从事于严肃的用途，比如原子弹模拟、气候模拟和高等物理学。当然，它们的花费也很高大上。在最新的超级计算机 [Top500][1] 排名中，中国国防科技大学研制的天河 2 号位居第一，而天河 2 号的建造耗资约 3.9 亿美元！
|
||||
|
||||
但是，也有一个超级计算机，是由博伊西州立大学电气和计算机工程系的一名在读博士 Joshua Kiepert [用树莓派构建完成][2]的，其建造成本低于2000美元。
|
||||
|
||||
不，这不是我编造的。它一个真实的超级计算机，由超频到 1GHz 的 [B 型树莓派][3]的 ARM11 处理器与 VideoCore IV GPU 组成。每个都配备了 512MB 的内存、一对 USB 端口和 1 个 10/100 BaseT 以太网端口。
|
||||
|
||||
那么天河 2 号和博伊西州立大学的超级计算机有什么共同点吗？它们都运行 Linux 系统。世界最快的超级计算机[前 500 强中有 486][4] 个也同样运行的是 Linux 系统。这是从 20 多年前就开始的格局。而现在的趋势是超级计算机开始由廉价单元组成，因为 Kiepert 的机器并不是唯一一个无所谓预算的超级计算机。
|
||||
|
||||
麻省大学达特茅斯分校的物理学副教授 Gaurav Khanna 创建了一台超级计算机仅用了[不足 200 台的 PlayStation3 视频游戏机][5]。
|
||||
|
||||
PlayStation 游戏机由一个 3.2 GHz 的基于 PowerPC 的 Power 处理器所驱动。每个都配有 512M 的内存。你现在仍然可以花 200 美元买到一个，尽管索尼将在年底逐步淘汰它们。Khanna 仅用了 16 个 PlayStation 3 构建了他第一台超级计算机，所以你也可以花费不到 4000 美元就拥有你自己的超级计算机。
|
||||
|
||||
这些机器可能是用玩具建成的，但他们不是玩具。Khanna 已经用它做了严肃的天体物理学研究。一个白帽子黑客组织使用了类似的 [PlayStation 3 超级计算机在 2008 年破解了 SSL 的 MD5 哈希算法][6]。
|
||||
|
||||
两年后，美国空军研究实验室研制的 [Condor Cluster，使用了 1760 个索尼的 PlayStation 3 的处理器][7]和168 个通用的图形处理单元。这个低廉的超级计算机，每秒运行约 500 TFLOP ，即每秒可进行 500 万亿次浮点运算。
|
||||
|
||||
其他的一些便宜且适用于构建家庭超级计算机的构件包括，专业并行处理板卡，比如信用卡大小的 [99 美元的 Parallella 板卡][8]，以及高端显卡，比如 [Nvidia 的 Titan Z][9] 和 [ AMD 的 FirePro W9100][10]。这些高端板卡的市场零售价约 3000 美元，一些想要一台梦幻般的机器的玩家为此参加了[英特尔极限大师赛：英雄联盟世界锦标赛][11]，要是甚至有机会得到了第一名的话，能获得超过 10 万美元奖金。另一方面，一个能够自己提供超过 2.5TFLOPS 计算能力的计算机，对于科学家和研究人员来说，这为他们提供了一个可以拥有自己专属的超级计算机的经济的方法。
|
||||
|
||||
而超级计算机与 Linux 的连接，这一切都始于 1994 年戈达德航天中心的第一个名为 [Beowulf 超级计算机][13]。
|
||||
|
||||
按照我们的标准，Beowulf 不能算是最优越的。但在那个时期，作为第一台自制的超级计算机，它的 16 个英特尔486DX 处理器和 10Mbps 的以太网总线，是个伟大的创举。[Beowulf 是由美国航空航天局的承建商 Don Becker 和 Thomas Sterling 所设计的][14]，是第一台“创客”超级计算机。它的“计算部件” 486DX PC，成本仅有几千美元。尽管它的速度只有个位数的 GFLOPS （吉拍，每秒10亿次）浮点运算，[Beowulf][15] 表明了你可以用商用现货（COTS）硬件和 Linux 创建超级计算机。
|
||||
|
||||
我真希望我参与创建了一部分，但是我 1994 年就离开了戈达德，开始了作为一名全职的科技记者的职业生涯。该死。
|
||||
|
||||
但是尽管我只是使用笔记本的记者，我依然能够体会到 COTS 和开源软件是如何永远的改变了超级计算机。我希望现在读这篇文章的你也能。因为，无论是 Raspberry Pi 集群，还是超过 300 万个英特尔的 Ivy Bridge 和 Xeon Phi 芯片的庞然大物，几乎所有当代的超级计算机都可以追溯到 Beowulf。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.computerworld.com/article/2960701/linux/for-linux-supercomputers-r-us.html
|
||||
|
||||
作者：[Steven J. Vaughan-Nichols][a]
|
||||
译者：[xiaoyu33](https://github.com/xiaoyu33)
|
||||
校对：[wxy](https://github.com/wxy)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.computerworld.com/author/Steven-J.-Vaughan_Nichols/
|
||||
[1]:http://www.top500.org/
|
||||
[2]:http://www.zdnet.com/article/build-your-own-supercomputer-out-of-raspberry-pi-boards/
|
||||
[3]:https://www.raspberrypi.org/products/model-b/
|
||||
[4]:http://www.zdnet.com/article/linux-still-rules-supercomputing/
|
||||
[5]:http://www.nytimes.com/2014/12/23/science/an-economical-way-to-save-progress.html?smid=fb-nytimes&smtyp=cur&bicmp=AD&bicmlukp=WT.mc_id&bicmst=1409232722000&bicmet=1419773522000&_r=4
|
||||
[6]:http://www.computerworld.com/article/2529932/cybercrime-hacking/researchers-hack-verisign-s-ssl-scheme-for-securing-web-sites.html
|
||||
[7]:http://phys.org/news/2010-12-air-playstation-3s-supercomputer.html
|
||||
[8]:http://www.zdnet.com/article/parallella-the-99-linux-supercomputer/
|
||||
[9]:http://blogs.nvidia.com/blog/2014/03/25/titan-z/
|
||||
[10]:http://www.amd.com/en-us/press-releases/Pages/amd-flagship-professional-2014apr7.aspx
|
||||
[11]:http://en.intelextrememasters.com/news/check-out-the-intel-extreme-masters-katowice-prize-money-distribution/
|
||||
|
||||
[13]:http://www.beowulf.org/overview/history.html
|
||||
[14]:http://yclept.ucdavis.edu/Beowulf/aboutbeowulf.html
|
||||
[15]:http://www.beowulf.org/
|
||||
@ -1,3 +1,5 @@
|
||||
translating by xiaoyu33
|
||||
|
||||
Tickr Is An Open-Source RSS News Ticker for Linux Desktops
|
||||
================================================================================
|
||||
|
||||
@ -92,4 +94,4 @@ via: http://www.omgubuntu.co.uk/2015/06/tickr-open-source-desktop-rss-news-ticke
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://plus.google.com/117485690627814051450/?rel=author
|
||||
[1]:apt://tickr
|
||||
[1]:apt://tickr
|
||||
|
||||
@ -1,100 +0,0 @@
|
||||
Translating by ZTinoZ
|
||||
5 heroes of the Linux world
|
||||
================================================================================
|
||||
Who are these people, seen and unseen, whose work affects all of us every day?
|
||||
|
||||
|
||||
Image courtesy [Christopher Michel/Flickr][1]
|
||||
|
||||
### High-flying penguins ###
|
||||
|
||||
Linux and open source is driven by passionate people who write best-of-breed software and then release the code to the public so anyone can use it, without any strings attached. (Well, there is one string attached and that’s licence.)
|
||||
|
||||
Who are these people? These heroes of the Linux world, whose work affects all of us every day. Allow me to introduce you.
|
||||
|
||||
|
||||
Image courtesy Swapnil Bhartiya
|
||||
|
||||
### Klaus Knopper ###
|
||||
|
||||
Klaus Knopper, an Austrian developer who lives in Germany, is the founder of Knoppix and Adriana Linux, which he developed for his blind wife.
|
||||
|
||||
Knoppix holds a very special place in heart of those Linux users who started using Linux before Ubuntu came along. What makes Knoppix so special is that it popularized the concept of Live CD. Unlike Windows or Mac OS X, you could run the entire operating system from the CD without installing anything on the system. It allowed new users to test Linux on their systems without formatting the hard drive. The live feature of Linux alone contributed heavily to its popularity.
|
||||
|
||||
|
||||
Image courtesy [Fórum Internacional Software Live/Flickr][2]
|
||||
|
||||
### Lennart Pottering ###
|
||||
|
||||
Lennart Pottering is yet another genius from Germany. He has written so many core components of a Linux (as well as BSD) system that it’s hard to keep track. Most of his work is towards the successors of aging or broken components of the Linux systems.
|
||||
|
||||
Pottering wrote the modern init system systemd, which shook the Linux world and created a [rift in the Debian community][3].
|
||||
|
||||
While Linus Torvalds has no problems with systemd, and praises it, he is not a huge fan of the way systemd developers (including the co-author Kay Sievers,) respond to bug reports and criticism. At one point Linus said on the LKML (Linux Kernel Mailing List) that he would [never work with Sievers][4].
|
||||
|
||||
Lennart is also the author of Pulseaudio, sound server on Linux and Avahi, zero-configuration networking (zeroconf) implementation.
|
||||
|
||||
|
||||
Image courtesy [Meego Com/Flickr][5]
|
||||
|
||||
### Jim Zemlin ###
|
||||
|
||||
Jim Zemlin isn't a developer, but as founder of The Linux Foundation he is certainly one of the most important figures of the Linux world.
|
||||
|
||||
In 2007, The Linux Foundation was formed as a result of merger between two open source bodies: the Free Standards Group and the Open Source Development Labs. Zemlin was the executive director of the Free Standards Group. Post-merger Zemlin became the executive director of The Linux Foundation and has held that position since.
|
||||
|
||||
Under his leadership, The Linux Foundation has become the central figure in the modern IT world and plays a very critical role for the Linux ecosystem. In order to ensure that key developers like Torvalds and Kroah-Hartman can focus on Linux, the foundation sponsors them as fellows.
|
||||
|
||||
Zemlin also made the foundation a bridge between companies so they can collaborate on Linux while at the same time competing in the market. The foundation also organizes many conferences around the world and [offers many courses for Linux developers][6].
|
||||
|
||||
People may think of Zemlin as Linus Torvalds' boss, but he refers to himself as "Linus Torvalds' janitor."
|
||||
|
||||
|
||||
Image courtesy [Coscup/Flickr][7]
|
||||
|
||||
### Greg Kroah-Hartman ###
|
||||
|
||||
Greg Kroah-Hartman is known as second-in-command of the Linux kernel. The ‘gentle giant’ is the maintainer of the stable branch of the kernel and of staging subsystem, USB, driver core, debugfs, kref, kobject, and the [sysfs][8] kernel subsystems along with many other components of a Linux system.
|
||||
|
||||
He is also credited for device drivers for Linux. One of his jobs is to travel around the globe, meet hardware makers and persuade them to make their drivers available for Linux. The next time you plug some random USB device to your system and it works out of the box, thank Kroah-Hartman. (Don't thank the distro. Some distros try to take credit for the work Kroah-Hartman or the Linux kernel did.)
|
||||
|
||||
Kroah-Hartman previously worked for Novell and then joined the Linux Foundation as a fellow, alongside Linus Torvalds.
|
||||
|
||||
Kroah-Hartman is the total opposite of Linus and never rants (at least publicly). One time there was some ripple was when he stated that [Canonical doesn’t contribute much to the Linux kernel][9].
|
||||
|
||||
On a personal level, Kroah-Hartman is extremely helpful to new developers and users and is easily accessible.
|
||||
|
||||
|
||||
Image courtesy Swapnil Bhartiya
|
||||
|
||||
### Linus Torvalds ###
|
||||
|
||||
No collection of Linux heroes would be complete without Linus Torvalds. He is the author of the Linux kernel, the most used open source technology on the planet and beyond. His software powers everything from space stations to supercomputers, military drones to mobile devices and tiny smartwatches. Linus remains the authority on the Linux kernel and makes the final decision on which patches to merge to the kernel.
|
||||
|
||||
Linux isn't Torvalds' only contribution open source. When he got fed-up with the existing software revision control systems, which his kernel heavily relied on, he wrote his own, called Git. Git enjoys the same reputation as Linux; it is the most used version control system in the world.
|
||||
|
||||
Torvalds is also a passionate scuba diver and when he found no decent dive logs for Linux, he wrote his own and called it SubSurface.
|
||||
|
||||
Torvalds is [well known for his rants][10] and once admitted that his ego is as big as a small planet. But he is also known for admitting his mistakes if he realizes he was wrong.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.itworld.com/article/2955001/linux/5-heros-of-the-linux-world.html
|
||||
|
||||
作者：[Swapnil Bhartiya][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.itworld.com/author/Swapnil-Bhartiya/
|
||||
[1]:https://flic.kr/p/siJ25M
|
||||
[2]:https://flic.kr/p/uTzj54
|
||||
[3]:http://www.itwire.com/business-it-news/open-source/66153-systemd-fallout-two-debian-technical-panel-members-resign
|
||||
[4]:http://www.linuxveda.com/2014/04/04/linus-torvalds-systemd-kay-sievers/
|
||||
[5]:https://flic.kr/p/9Lnhpu
|
||||
[6]:http://www.itworld.com/article/2951968/linux/linux-foundation-offers-cheaper-courses-and-certifications-for-india.html
|
||||
[7]:https://flic.kr/p/hBv8Pp
|
||||
[8]:https://en.wikipedia.org/wiki/Sysfs
|
||||
[9]:https://www.youtube.com/watch?v=CyHAeGBFS8k
|
||||
[10]:http://www.itworld.com/article/2873200/operating-systems/11-technologies-that-tick-off-linus-torvalds.html
|
||||
@ -1,60 +0,0 @@
|
||||
Translating by xiaoyu33
|
||||
For Linux, Supercomputers R Us
|
||||
================================================================================
|
||||
|
||||
Credit: Michel Ngilen, CC BY 2.0, via Wikimedia Commons
|
||||
|
||||
> Almost all supercomputers run Linux, including the ones built from Raspberry Pi boards and PlayStation 3 game consoles
|
||||
|
||||
Supercomputers are serious things, called on to do serious computing. They tend to be engaged in serious pursuits like atomic bomb simulations, climate modeling and high-level physics. Naturally, they cost serious money. At the very top of the latest [Top500][1] supercomputer ranking is the Tianhe-2 supercomputer at China’s National University of Defense Technology. It cost about $390 million to build.
|
||||
|
||||
But then there’s the supercomputer that Joshua Kiepert, a doctoral student at Boise State’s Electrical and Computer Engineering department, [created with Raspberry Pi computers][2].It cost less than $2,000.
|
||||
|
||||
No, I’m not making that up. It’s an honest-to-goodness supercomputer made from overclocked 1-GHz [Model B Raspberry Pi][3] ARM11 processors with Videocore IV GPUs. Each one comes with 512MB of RAM, a pair of USB ports and a 10/100 BaseT Ethernet port.
|
||||
|
||||
And what do the Tianhe-2 and the Boise State supercomputer have in common? They both run Linux. As do [486 out of the world’s fastest 500 supercomputers][4]. It’s part of a domination of the category that began over 20 years ago. And now it’s trickling down to built-on-the-cheap supercomputers. Because Kiepert’s machine isn’t the only budget number cruncher out there.
|
||||
|
||||
Gaurav Khanna, an associate professor of physics at the University of Massachusetts Dartmouth, created a [supercomputer with something shy of 200 PlayStation 3 video game consoles][5].
|
||||
|
||||
The PlayStations are powered by a 3.2-GHz PowerPC-based Power Processing Element. Each comes with 512MB of RAM. You can still buy one, although Sony will be phasing them out by year’s end, for just over $200. Khanna started with only 16 PlayStation 3s for his first supercomputer, so you too could put a supercomputer on your credit card for less than four grand.
|
||||
|
||||
These machines may be built from toys, but they’re not playthings. Khanna has done serious astrophysics on his rig. A white-hat hacking group used a similar [PlayStation 3 supercomputer in 2008 to crack the SSL MD5 hashing algorithm][6] in 2008.
|
||||
|
||||
Two years later, the Air Force Research Laboratory [Condor Cluster was using 1,760 Sony PlayStation 3 processors][7] and 168 general-purpose graphical processing units. This bargain-basement supercomputer runs at about 500TFLOPs, or 500 trillion floating point operations per second.
|
||||
|
||||
Other cheap options for home supercomputers include specialist parallel-processing boards such as the [$99 credit-card-sized Parallella board][8], and high-end graphics boards such as [Nvidia’s Titan Z][9] and [AMD’s FirePro W9100][10]. Those high-end boards, coveted by gamers with visions of a dream machine or even a chance at winning the first-place prize of over $100,000 in the [Intel Extreme Masters World Championship League of][11] [Legends][12], cost considerably more, retailing for about $3,000. On the other hand, a single one can deliver over 2.5TFLOPS all by itself, and for scientists and researchers, they offer an affordable way to get a supercomputer they can call their own.
|
||||
|
||||
As for the Linux connection, that all started in 1994 at the Goddard Space Flight Center with the first [Beowulf supercomputer][13].
|
||||
|
||||
By our standards, there wasn’t much that was super about the first Beowulf. But in its day, the first homemade supercomputer, with its 16 Intel 486DX processors and 10Mbps Ethernet for the bus, was great. [Beowulf, designed by NASA contractors Don Becker and Thomas Sterling][14], was the first “maker” supercomputer. Its “compute components,” 486DX PCs, cost only a few thousand dollars. While its speed was only in single-digit gigaflops, [Beowulf][15] showed you could build supercomputers from commercial off-the-shelf (COTS) hardware and Linux.
|
||||
|
||||
I wish I’d had a part in its creation, but I’d already left Goddard by 1994 for a career as a full-time technology journalist. Darn it!
|
||||
|
||||
But even from this side of my reporter’s notebook, I can still appreciate how COTS and open-source software changed supercomputing forever. I hope you can too. Because, whether it’s a cluster of Raspberry Pis or a monster with over 3 million Intel Ivy Bridge and Xeon Phi chips, almost all of today’s supercomputers trace their ancestry to Beowulf.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via:
|
||||
|
||||
作者：[Steven J. Vaughan-Nichols][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.computerworld.com/author/Steven-J.-Vaughan_Nichols/
|
||||
[1]:http://www.top500.org/
|
||||
[2]:http://www.zdnet.com/article/build-your-own-supercomputer-out-of-raspberry-pi-boards/
|
||||
[3]:https://www.raspberrypi.org/products/model-b/
|
||||
[4]:http://www.zdnet.com/article/linux-still-rules-supercomputing/
|
||||
[5]:http://www.nytimes.com/2014/12/23/science/an-economical-way-to-save-progress.html?smid=fb-nytimes&smtyp=cur&bicmp=AD&bicmlukp=WT.mc_id&bicmst=1409232722000&bicmet=1419773522000&_r=4
|
||||
[6]:http://www.computerworld.com/article/2529932/cybercrime-hacking/researchers-hack-verisign-s-ssl-scheme-for-securing-web-sites.html
|
||||
[7]:http://phys.org/news/2010-12-air-playstation-3s-supercomputer.html
|
||||
[8]:http://www.zdnet.com/article/parallella-the-99-linux-supercomputer/
|
||||
[9]:http://blogs.nvidia.com/blog/2014/03/25/titan-z/
|
||||
[10]:http://www.amd.com/en-us/press-releases/Pages/amd-flagship-professional-2014apr7.aspx
|
||||
[11]:http://en.intelextrememasters.com/news/check-out-the-intel-extreme-masters-katowice-prize-money-distribution/
|
||||
[12]:http://www.google.com/url?q=http%3A%2F%2Fen.intelextrememasters.com%2Fnews%2Fcheck-out-the-intel-extreme-masters-katowice-prize-money-distribution%2F&sa=D&sntz=1&usg=AFQjCNE6yoAGGz-Hpi2tPF4gdhuPBEckhQ
|
||||
[13]:http://www.beowulf.org/overview/history.html
|
||||
[14]:http://yclept.ucdavis.edu/Beowulf/aboutbeowulf.html
|
||||
[15]:http://www.beowulf.org/
|
||||
@ -1,183 +0,0 @@
|
||||
Translating by Ping
|
||||
How to set up a Replica Set on MongoDB
|
||||
================================================================================
|
||||
MongoDB has become the most famous NoSQL database on the market. MongoDB is document-oriented, and its scheme-free design makes it a really attractive solution for all kinds of web applications. One of the features that I like the most is Replica Set, where multiple copies of the same data set are maintained by a group of mongod nodes for redundancy and high availability.
|
||||
|
||||
This tutorial describes how to configure a Replica Set on MonoDB.
|
||||
|
||||
The most common configuration for a Replica Set involves one primary and multiple secondary nodes. The replication will then be initiated from the primary toward the secondaries. Replica Sets can not only provide database protection against unexpected hardware failure and service downtime, but also improve read throughput of database clients as they can be configured to read from different nodes.
|
||||
|
||||
### Set up the Environment ###
|
||||
|
||||
In this tutorial, we are going to set up a Replica Set with one primary and two secondary nodes.
|
||||
|
||||
|
||||
|
||||
In order to implement this lab, we will use three virtual machines (VMs) running on VirtualBox. I am going to install Ubuntu 14.04 on the VMs, and install official packages for Mongodb.
|
||||
|
||||
I am going to set up a necessary environment on one VM instance, and then clone it to the other two VM instances. Thus pick one VM named master, and perform the following installations.
|
||||
|
||||
First, we need to add the MongoDB key for apt:
|
||||
|
||||
$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
|
||||
|
||||
Then we need to add the official MongoDB repository to our source.list:
|
||||
|
||||
$ sudo su
|
||||
# echo "deb http://repo.mongodb.org/apt/ubuntu "$(lsb_release -sc)"/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
|
||||
|
||||
Let's update repositories and install MongoDB.
|
||||
|
||||
$ sudo apt-get update
|
||||
$ sudo apt-get install -y mongodb-org
|
||||
|
||||
Now let's make some changes in /etc/mongodb.conf.
|
||||
|
||||
auth = true
|
||||
dbpath=/var/lib/mongodb
|
||||
logpath=/var/log/mongodb/mongod.log
|
||||
logappend=true
|
||||
keyFile=/var/lib/mongodb/keyFile
|
||||
replSet=myReplica
|
||||
|
||||
The first line is to make sure that we are going to have authentication on our database. keyFile is to set up a keyfile that is going to be used by MongoDB to replicate between nodes. replSet sets up the name of our replica set.
|
||||
|
||||
Now we are going to create our keyfile, so that it can be in all our instances.
|
||||
|
||||
$ echo -n "MyRandomStringForReplicaSet" | md5sum > keyFile
|
||||
|
||||
This will create keyfile that contains a MD5 string, but it has some noise that we need to clean up before using it in MongoDB. Use the following command to clean it up:
|
||||
|
||||
$ echo -n "MyReplicaSetKey" | md5sum|grep -o "[0-9a-z]\+" > keyFile
|
||||
|
||||
What grep command does is to print MD5 string with no spaces or other characters that we don't want.
|
||||
|
||||
Now we are going to make the keyfile ready for use:
|
||||
|
||||
$ sudo cp keyFile /var/lib/mongodb
|
||||
$ sudo chown mongodb:nogroup keyFile
|
||||
$ sudo chmod 400 keyFile
|
||||
|
||||
Now we have our Ubuntu VM ready to be cloned. Power it off, and clone it to the other VMs.
|
||||
|
||||
|
||||
|
||||
I name the cloned VMs secondary1 and secondary2. Make sure to reinitialize the MAC address of cloned VMs and clone full disks.
|
||||
|
||||
|
||||
|
||||
All three VM instances should be on the same network to communicate with each other. For this, we are going to attach all three VMs to "Internet Network".
|
||||
|
||||
It is recommended that each VM instances be assigned a static IP address, as opposed to DHCP IP address, so that the VMs will not lose connectivity among themselves when a DHCP server assigns different IP addresses to them.
|
||||
|
||||
Let's edit /etc/networks/interfaces of each VM as follows.
|
||||
|
||||
On primary:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.2
|
||||
netmask 255.255.255.0
|
||||
|
||||
On secondary1:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.3
|
||||
netmask 255.255.255.0
|
||||
|
||||
On secondary2:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.4
|
||||
netmask 255.255.255.0
|
||||
|
||||
Another file that needs to be set up is /etc/hosts, because we don't have DNS. We need to set the hostnames in /etc/hosts.
|
||||
|
||||
On primary:
|
||||
|
||||
127.0.0.1 localhost primary
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
On secondary1:
|
||||
|
||||
127.0.0.1 localhost secondary1
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
On secondary2:
|
||||
|
||||
127.0.0.1 localhost secondary2
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
Check connectivity among themselves by using ping command:
|
||||
|
||||
$ ping primary
|
||||
$ ping secondary1
|
||||
$ ping secondary2
|
||||
|
||||
### Set up a Replica Set ###
|
||||
|
||||
After verifying connectivity among VMs, we can go ahead and create the admin user so that we can start working on the Replica Set.
|
||||
|
||||
On primary node, open /etc/mongodb.conf, and comment out two lines that start with auth and replSet:
|
||||
|
||||
dbpath=/var/lib/mongodb
|
||||
logpath=/var/log/mongodb/mongod.log
|
||||
logappend=true
|
||||
#auth = true
|
||||
keyFile=/var/lib/mongodb/keyFile
|
||||
#replSet=myReplica
|
||||
|
||||
Restart mongod daemon.
|
||||
|
||||
$ sudo service mongod restart
|
||||
|
||||
Create an admin user after conencting to MongoDB:
|
||||
|
||||
> use admin
|
||||
> db.createUser({
|
||||
user:"admin",
|
||||
pwd:"
|
||||
})
|
||||
$ sudo service mongod restart
|
||||
|
||||
Connect to MongoDB and use these commands to add secondary1 and secondary2 to our Replicat Set.
|
||||
|
||||
> use admin
|
||||
> db.auth("admin","myreallyhardpassword")
|
||||
> rs.initiate()
|
||||
> rs.add ("secondary1:27017")
|
||||
> rs.add("secondary2:27017")
|
||||
|
||||
Now that we have our Replica Set, we can start working on our project. Consult the [official driver documentation][1] to see how to connect to a Replica Set. In case you want to query from shell, you have to connect to primary instance to insert or query the database. Secondary nodes will not let you do that. If you attempt to access the database on a secondary node, you will get this error message:
|
||||
|
||||
myReplica:SECONDARY>
|
||||
myReplica:SECONDARY> show databases
|
||||
2015-05-10T03:09:24.131+0000 E QUERY Error: listDatabases failed:{ "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }
|
||||
at Error ()
|
||||
at Mongo.getDBs (src/mongo/shell/mongo.js:47:15)
|
||||
at shellHelper.show (src/mongo/shell/utils.js:630:33)
|
||||
at shellHelper (src/mongo/shell/utils.js:524:36)
|
||||
at (shellhelp2):1:1 at src/mongo/shell/mongo.js:47
|
||||
|
||||
I hope you find this tutorial useful. You can use Vagrant to automate your local environments and help you code faster.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://xmodulo.com/setup-replica-set-mongodb.html
|
||||
|
||||
作者：[Christopher Valerio][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://xmodulo.com/author/valerio
|
||||
[1]:http://docs.mongodb.org/ecosystem/drivers/
|
||||
@ -1,349 +0,0 @@
|
||||
translating wi-cuckoo
|
||||
Shilpa Nair Shares Her Interview Experience on RedHat Linux Package Management
|
||||
================================================================================
|
||||
**Shilpa Nair has just graduated in the year 2015. She went to apply for Trainee position in a National News Television located in Noida, Delhi. When she was in the last year of graduation and searching for help on her assignments she came across Tecmint. Since then she has been visiting Tecmint regularly.**
|
||||
|
||||
|
||||
|
||||
Linux Interview Questions on RPM
|
||||
|
||||
All the questions and answers are rewritten based upon the memory of Shilpa Nair.
|
||||
|
||||
> “Hi friends! I am Shilpa Nair from Delhi. I have completed my graduation very recently and was hunting for a Trainee role soon after my degree. I have developed a passion for UNIX since my early days in the collage and I was looking for a role that suits me and satisfies my soul. I was asked a lots of questions and most of them were basic questions related to RedHat Package Management.”
|
||||
|
||||
Here are the questions, that I was asked and their corresponding answers. I am posting only those questions that are related to RedHat GNU/Linux Package Management, as they were mainly asked.
|
||||
|
||||
### 1. How will you find if a package is installed or not? Say you have to find if ‘nano’ is installed or not, what will you do? ###
|
||||
|
||||
> **Answer** : To find the package nano, weather installed or not, we can use rpm command with the option -q is for query and -a stands for all the installed packages.
|
||||
>
|
||||
> # rpm -qa nano
|
||||
> OR
|
||||
> # rpm -qa | grep -i nano
|
||||
>
|
||||
> nano-2.3.1-10.el7.x86_64
|
||||
>
|
||||
> Also the package name must be complete, an incomplete package name will return the prompt without printing anything which means that package (incomplete package name) is not installed. It can be understood easily by the example below:
|
||||
>
|
||||
> We generally substitute vim command with vi. But if we find package vi/vim we will get no result on the standard output.
|
||||
>
|
||||
> # vi
|
||||
> # vim
|
||||
>
|
||||
> However we can clearly see that the package is installed by firing vi/vim command. Here is culprit is incomplete file name. If we are not sure of the exact file-name we can use wildcard as:
|
||||
>
|
||||
> # rpm -qa vim*
|
||||
>
|
||||
> vim-minimal-7.4.160-1.el7.x86_64
|
||||
>
|
||||
> This way we can find information about any package, if installed or not.
|
||||
|
||||
### 2. How will you install a package XYZ using rpm? ###
|
||||
|
||||
> **Answer** : We can install any package (*.rpm) using rpm command a shown below, here options -i (install), -v (verbose or display additional information) and -h (print hash mark during package installation).
|
||||
>
|
||||
> # rpm -ivh peazip-1.11-1.el6.rf.x86_64.rpm
|
||||
>
|
||||
> Preparing... ################################# [100%]
|
||||
> Updating / installing...
|
||||
> 1:peazip-1.11-1.el6.rf ################################# [100%]
|
||||
>
|
||||
> If upgrading a package from earlier version -U switch should be used, option -v and -h follows to make sure we get a verbose output along with hash Mark, that makes it readable.
|
||||
|
||||
### 3. You have installed a package (say httpd) and now you want to see all the files and directories installed and created by the above package. What will you do? ###
|
||||
|
||||
> **Answer** : We can list all the files (Linux treat everything as file including directories) installed by the package httpd using options -l (List all the files) and -q (is for query).
|
||||
>
|
||||
> # rpm -ql httpd
|
||||
>
|
||||
> /etc/httpd
|
||||
> /etc/httpd/conf
|
||||
> /etc/httpd/conf.d
|
||||
> ...
|
||||
|
||||
### 4. You are supposed to remove a package say postfix. What will you do? ###
|
||||
|
||||
> **Answer** : First we need to know postfix was installed by what package. Find the package name that installed postfix using options -e erase/uninstall a package) and –v (verbose output).
|
||||
>
|
||||
> # rpm -qa postfix*
|
||||
>
|
||||
> postfix-2.10.1-6.el7.x86_64
|
||||
>
|
||||
> and then remove postfix as:
|
||||
>
|
||||
> # rpm -ev postfix-2.10.1-6.el7.x86_64
|
||||
>
|
||||
> Preparing packages...
|
||||
> postfix-2:3.0.1-2.fc22.x86_64
|
||||
|
||||
### 5. Get detailed information about an installed package, means information like Version, Release, Install Date, Size, Summary and a brief description. ###
|
||||
|
||||
> **Answer** : We can get detailed information about an installed package by using option -qa with rpm followed by package name.
|
||||
>
|
||||
> For example to find details of package openssh, all I need to do is:
|
||||
>
|
||||
> # rpm -qi openssh
|
||||
>
|
||||
> [root@tecmint tecmint]# rpm -qi openssh
|
||||
> Name : openssh
|
||||
> Version : 6.8p1
|
||||
> Release : 5.fc22
|
||||
> Architecture: x86_64
|
||||
> Install Date: Thursday 28 May 2015 12:34:50 PM IST
|
||||
> Group : Applications/Internet
|
||||
> Size : 1542057
|
||||
> License : BSD
|
||||
> ....
|
||||
|
||||
### 6. You are not sure about what are the configuration files provided by a specific package say httpd. How will you find list of all the configuration files provided by httpd and their location. ###
|
||||
|
||||
> **Answer** : We need to run option -c followed by package name with rpm command and it will list the name of all the configuration file and their location.
|
||||
>
|
||||
> # rpm -qc httpd
|
||||
>
|
||||
> /etc/httpd/conf.d/autoindex.conf
|
||||
> /etc/httpd/conf.d/userdir.conf
|
||||
> /etc/httpd/conf.d/welcome.conf
|
||||
> /etc/httpd/conf.modules.d/00-base.conf
|
||||
> /etc/httpd/conf/httpd.conf
|
||||
> /etc/sysconfig/httpd
|
||||
>
|
||||
> Similarly we can list all the associated document files as:
|
||||
>
|
||||
> # rpm -qd httpd
|
||||
>
|
||||
> /usr/share/doc/httpd/ABOUT_APACHE
|
||||
> /usr/share/doc/httpd/CHANGES
|
||||
> /usr/share/doc/httpd/LICENSE
|
||||
> ...
|
||||
>
|
||||
> also, we can list the associated License file as:
|
||||
>
|
||||
> # rpm -qL openssh
|
||||
>
|
||||
> /usr/share/licenses/openssh/LICENCE
|
||||
>
|
||||
> Not to mention that the option -d and option -L in the above command stands for ‘documents‘ and ‘License‘, respectively.
|
||||
|
||||
### 7. You came across a configuration file located at ‘/usr/share/alsa/cards/AACI.conf’ and you are not sure this configuration file is associated with what package. How will you find out the parent package name? ###
|
||||
|
||||
> **Answer** : When a package is installed, the relevant information gets stored in the database. So it is easy to trace what provides the above package using option -qf (-f query packages owning files).
|
||||
>
|
||||
> # rpm -qf /usr/share/alsa/cards/AACI.conf
|
||||
> alsa-lib-1.0.28-2.el7.x86_64
|
||||
>
|
||||
> Similarly we can find (what provides) information about any sub-packge, document files and License files.
|
||||
|
||||
### 8. How will you find list of recently installed software’s using rpm? ###
|
||||
|
||||
> **Answer** : As said earlier, everything being installed is logged in database. So it is not difficult to query the rpm database and find the list of recently installed software’s.
|
||||
>
|
||||
> We can do this by running the below commands using option –last (prints the most recent installed software’s).
|
||||
>
|
||||
> # rpm -qa --last
|
||||
>
|
||||
> The above command will print all the packages installed in a order such that, the last installed software appears at the top.
|
||||
>
|
||||
> If our concern is to find out specific package, we can grep that package (say sqlite) from the list, simply as:
|
||||
>
|
||||
> # rpm -qa --last | grep -i sqlite
|
||||
>
|
||||
> sqlite-3.8.10.2-1.fc22.x86_64 Thursday 18 June 2015 05:05:43 PM IST
|
||||
>
|
||||
> We can also get a list of 10 most recently installed software simply as:
|
||||
>
|
||||
> # rpm -qa --last | head
|
||||
>
|
||||
> We can refine the result to output a more custom result simply as:
|
||||
>
|
||||
> # rpm -qa --last | head -n 2
|
||||
>
|
||||
> In the above command -n represents number followed by a numeric value. The above command prints a list of 2 most recent installed software.
|
||||
|
||||
### 9. Before installing a package, you are supposed to check its dependencies. What will you do? ###
|
||||
|
||||
> **Answer** : To check the dependencies of a rpm package (XYZ.rpm), we can use switches -q (query package), -p (query a package file) and -R (Requires / List packages on which this package depends i.e., dependencies).
|
||||
>
|
||||
> # rpm -qpR gedit-3.16.1-1.fc22.i686.rpm
|
||||
>
|
||||
> /bin/sh
|
||||
> /usr/bin/env
|
||||
> glib2(x86-32) >= 2.40.0
|
||||
> gsettings-desktop-schemas
|
||||
> gtk3(x86-32) >= 3.16
|
||||
> gtksourceview3(x86-32) >= 3.16
|
||||
> gvfs
|
||||
> libX11.so.6
|
||||
> ...
|
||||
|
||||
### 10. Is rpm a front-end Package Management Tool? ###
|
||||
|
||||
> **Answer** : No! rpm is a back-end package management for RPM based Linux Distribution.
|
||||
>
|
||||
> [YUM][1] which stands for Yellowdog Updater Modified is the front-end for rpm. YUM automates the overall process of resolving dependencies and everything else.
|
||||
>
|
||||
> Very recently [DNF][2] (Dandified YUM) replaced YUM in Fedora 22. Though YUM is still available to be used in RHEL and CentOS, we can install dnf and use it alongside of YUM. DNF is said to have a lots of improvement over YUM.
|
||||
>
|
||||
> Good to know, you keep yourself updated. Lets move to the front-end part.
|
||||
|
||||
### 11. How will you list all the enabled repolist on a system. ###
|
||||
|
||||
> **Answer** : We can list all the enabled repos on a system simply using following commands.
|
||||
>
|
||||
> # yum repolist
|
||||
> or
|
||||
> # dnf repolist
|
||||
>
|
||||
> Last metadata expiration check performed 0:30:03 ago on Mon Jun 22 16:50:00 2015.
|
||||
> repo id repo name status
|
||||
> *fedora Fedora 22 - x86_64 44,762
|
||||
> ozonos Repository for Ozon OS 61
|
||||
> *updates Fedora 22 - x86_64 - Updates
|
||||
>
|
||||
> The above command will only list those repos that are enabled. If we need to list all the repos, enabled or not, we can do.
|
||||
>
|
||||
> # yum repolist all
|
||||
> or
|
||||
> # dnf repolist all
|
||||
>
|
||||
> Last metadata expiration check performed 0:29:45 ago on Mon Jun 22 16:50:00 2015.
|
||||
> repo id repo name status
|
||||
> *fedora Fedora 22 - x86_64 enabled: 44,762
|
||||
> fedora-debuginfo Fedora 22 - x86_64 - Debug disabled
|
||||
> fedora-source Fedora 22 - Source disabled
|
||||
> ozonos Repository for Ozon OS enabled: 61
|
||||
> *updates Fedora 22 - x86_64 - Updates enabled: 5,018
|
||||
> updates-debuginfo Fedora 22 - x86_64 - Updates - Debug
|
||||
|
||||
### 12. How will you list all the available and installed packages on a system? ###
|
||||
|
||||
> **Answer** : To list all the available packages on a system, we can do:
|
||||
>
|
||||
> # yum list available
|
||||
> or
|
||||
> # dnf list available
|
||||
>
|
||||
> ast metadata expiration check performed 0:34:09 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Available Packages
|
||||
> 0ad.x86_64 0.0.18-1.fc22 fedora
|
||||
> 0ad-data.noarch 0.0.18-1.fc22 fedora
|
||||
> 0install.x86_64 2.6.1-2.fc21 fedora
|
||||
> 0xFFFF.x86_64 0.3.9-11.fc22 fedora
|
||||
> 2048-cli.x86_64 0.9-4.git20141214.723738c.fc22 fedora
|
||||
> 2048-cli-nocurses.x86_64 0.9-4.git20141214.723738c.fc22 fedora
|
||||
> ....
|
||||
>
|
||||
> To list all the installed Packages on a system, we can do.
|
||||
>
|
||||
> # yum list installed
|
||||
> or
|
||||
> # dnf list installed
|
||||
>
|
||||
> Last metadata expiration check performed 0:34:30 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Installed Packages
|
||||
> GeoIP.x86_64 1.6.5-1.fc22 @System
|
||||
> GeoIP-GeoLite-data.noarch 2015.05-1.fc22 @System
|
||||
> NetworkManager.x86_64 1:1.0.2-1.fc22 @System
|
||||
> NetworkManager-libnm.x86_64 1:1.0.2-1.fc22 @System
|
||||
> aajohan-comfortaa-fonts.noarch 2.004-4.fc22 @System
|
||||
> ....
|
||||
>
|
||||
> To list all the available and installed packages on a system, we can do.
|
||||
>
|
||||
> # yum list
|
||||
> or
|
||||
> # dnf list
|
||||
>
|
||||
> Last metadata expiration check performed 0:32:56 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Installed Packages
|
||||
> GeoIP.x86_64 1.6.5-1.fc22 @System
|
||||
> GeoIP-GeoLite-data.noarch 2015.05-1.fc22 @System
|
||||
> NetworkManager.x86_64 1:1.0.2-1.fc22 @System
|
||||
> NetworkManager-libnm.x86_64 1:1.0.2-1.fc22 @System
|
||||
> aajohan-comfortaa-fonts.noarch 2.004-4.fc22 @System
|
||||
> acl.x86_64 2.2.52-7.fc22 @System
|
||||
> ....
|
||||
|
||||
### 13. How will you install and update a package and a group of packages separately on a system using YUM/DNF? ###
|
||||
|
||||
> Answer : To Install a package (say nano), we can do,
|
||||
>
|
||||
> # yum install nano
|
||||
>
|
||||
> To Install a Group of Package (say Haskell), we can do.
|
||||
>
|
||||
> # yum groupinstall 'haskell'
|
||||
>
|
||||
> To update a package (say nano), we can do.
|
||||
>
|
||||
> # yum update nano
|
||||
>
|
||||
> To update a Group of Package (say Haskell), we can do.
|
||||
>
|
||||
> # yum groupupdate 'haskell'
|
||||
|
||||
### 14. How will you SYNC all the installed packages on a system to stable release? ###
|
||||
|
||||
> **Answer** : We can sync all the packages on a system (say CentOS or Fedora) to stable release as,
|
||||
>
|
||||
> # yum distro-sync [On CentOS/RHEL]
|
||||
> or
|
||||
> # dnf distro-sync [On Fedora 20 Onwards]
|
||||
|
||||
Seems you have done a good homework before coming for the interview,Good!. Before proceeding further I just want to ask one more question.
|
||||
|
||||
### 15. Are you familiar with YUM local repository? Have you tried making a Local YUM repository? Let me know in brief what you will do to create a local YUM repo. ###
|
||||
|
||||
> **Answer** : First I would like to Thank you Sir for appreciation. Coming to question, I must admit that I am quiet familiar with Local YUM repositories and I have already implemented it for testing purpose in my local machine.
|
||||
>
|
||||
> 1. To set up Local YUM repository, we need to install the below three packages as:
|
||||
>
|
||||
> # yum install deltarpm python-deltarpm createrepo
|
||||
>
|
||||
> 2. Create a directory (say /home/$USER/rpm) and copy all the RPMs from RedHat/CentOS DVD to that folder.
|
||||
>
|
||||
> # mkdir /home/$USER/rpm
|
||||
> # cp /path/to/rpm/on/DVD/*.rpm /home/$USER/rpm
|
||||
>
|
||||
> 3. Create base repository headers as.
|
||||
>
|
||||
> # createrepo -v /home/$USER/rpm
|
||||
>
|
||||
> 4. Create the .repo file (say abc.repo) at the location /etc/yum.repos.d simply as:
|
||||
>
|
||||
> cd /etc/yum.repos.d && cat << EOF > abc.repo
|
||||
> [local-installation]name=yum-local
|
||||
> baseurl=file:///home/$USER/rpm
|
||||
> enabled=1
|
||||
> gpgcheck=0
|
||||
> EOF
|
||||
|
||||
**Important**: Make sure to remove $USER with user_name.
|
||||
|
||||
That’s all we need to do to create a Local YUM repository. We can now install applications from here, that is relatively fast, secure and most important don’t need an Internet connection.
|
||||
|
||||
Okay! It was nice interviewing you. I am done. I am going to suggest your name to HR. You are a young and brilliant candidate we would like to have in our organization. If you have any question you may ask me.
|
||||
|
||||
**Me**: Sir, it was really a very nice interview and I feel very lucky today, to have cracked the interview..
|
||||
|
||||
Obviously it didn’t end here. I asked a lots of questions like the project they are handling. What would be my role and responsibility and blah..blah..blah
|
||||
|
||||
Friends, by the time all these were documented I have been called for HR round which is 3 days from now. Hope I do my best there as well. All your blessings will count.
|
||||
|
||||
Thankyou friends and Tecmint for taking time and documenting my experience. Mates I believe Tecmint is doing some really extra-ordinary which must be praised. When we share ours experience with other, other get to know many things from us and we get to know our mistakes.
|
||||
|
||||
It enhances our confidence level. If you have given any such interview recently, don’t keep it to yourself. Spread it! Let all of us know that. You may use the below form to share your experience with us.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-rpm-package-management-interview-questions/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/20-linux-yum-yellowdog-updater-modified-commands-for-package-mangement/
|
||||
[2]:http://www.tecmint.com/dnf-commands-for-fedora-rpm-package-management/
|
||||
@ -1,3 +1,4 @@
|
||||
Translating by ZTinoZ
|
||||
Installation Guide for Puppet on Ubuntu 15.04
|
||||
================================================================================
|
||||
Hi everyone, today in this article we'll learn how to install puppet to manage your server infrastructure running ubuntu 15.04. Puppet is an open source software configuration management tool which is developed and maintained by Puppet Labs that allows us to automate the provisioning, configuration and management of a server infrastructure. Whether we're managing just a few servers or thousands of physical and virtual machines to orchestration and reporting, puppet automates tasks that system administrators often do manually which frees up time and mental space so sysadmins can work on improving other aspects of your overall setup. It ensures consistency, reliability and stability of the automated jobs processed. It facilitates closer collaboration between sysadmins and developers, enabling more efficient delivery of cleaner, better-designed code. Puppet is available in two solutions configuration management and data center automation. They are **puppet open source and puppet enterprise**. Puppet open source is a flexible, customizable solution available under the Apache 2.0 license, designed to help system administrators automate the many repetitive tasks they regularly perform. Whereas puppet enterprise edition is a proven commercial solution for diverse enterprise IT environments which lets us get all the benefits of open source puppet, plus puppet apps, commercial-only enhancements, supported modules and integrations, and the assurance of a fully supported platform. Puppet uses SSL certificates to authenticate communication between master and agent nodes.
|
||||
@ -426,4 +427,4 @@ via: http://linoxide.com/linux-how-to/install-puppet-ubuntu-15-04/
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linoxide.com/author/arunp/
|
||||
[1]:https://docs.puppetlabs.com/puppet/latest/reference/config_file_main.html
|
||||
[1]:https://docs.puppetlabs.com/puppet/latest/reference/config_file_main.html
|
||||
|
||||
@ -0,0 +1,203 @@
|
||||
How to Install Snort and Usage in Ubuntu 15.04
|
||||
================================================================================
|
||||
Intrusion detection in a network is important for IT security. Intrusion Detection System used for the detection of illegal and malicious attempts in the network. Snort is well-known open source intrusion detection system. Web interface (Snorby) can be used for better analysis of alerts. Snort can be used as an intrusion prevention system with iptables/pf firewall. In this article, we will install and configure an open source IDS system snort.
|
||||
|
||||
### Snort Installation ###
|
||||
|
||||
#### Prerequisite ####
|
||||
|
||||
Data Acquisition library (DAQ) is used by the snort for abstract calls to packet capture libraries. It is available on snort website. Downloading process is shown in the following screenshot.
|
||||
|
||||
|
||||
|
||||
Extract it and run ./configure, make and make install commands for DAQ installation. However, DAQ required other tools therefore ./configure script will generate following errors .
|
||||
|
||||
flex and bison error
|
||||
|
||||
|
||||
|
||||
libpcap error.
|
||||
|
||||
|
||||
|
||||
Therefore first install flex/bison and libcap before DAQ installation which is shown in the figure.
|
||||
|
||||
|
||||
|
||||
Installation of libpcap development library is shown below
|
||||
|
||||
|
||||
|
||||
After installation of necessary tools, again run ./configure script which will show following output.
|
||||
|
||||
|
||||
|
||||
make and make install commands result is shown in the following screens.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
After successful installation of DAQ, now we will install snort. Downloading using wget is shown in the below figure.
|
||||
|
||||
|
||||
|
||||
Extract compressed package using below given command.
|
||||
|
||||
#tar -xvzf snort-2.9.7.3.tar.gz
|
||||
|
||||
|
||||
|
||||
Create installation directory and set prefix parameter in the configure script. It is also recommended to enable sourcefire flag for Packet Performance Monitoring (PPM).
|
||||
|
||||
#mkdir /usr/local/snort
|
||||
|
||||
#./configure --prefix=/usr/local/snort/ --enable-sourcefire
|
||||
|
||||
|
||||
|
||||
Configure script generates error due to missing libpcre-dev , libdumbnet-dev and zlib development libraries.
|
||||
|
||||
error due to missing libpcre library.
|
||||
|
||||
|
||||
|
||||
error due to missing dnet (libdumbnet) library.
|
||||
|
||||
|
||||
|
||||
configure script generate error due to missing zlib library.
|
||||
|
||||
|
||||
|
||||
Installation of all required development libraries is shown in the next screenshots.
|
||||
|
||||
# aptitude install libpcre3-dev
|
||||
|
||||
|
||||
|
||||
# aptitude install libdumbnet-dev
|
||||
|
||||
|
||||
|
||||
# aptitude install zlib1g-dev
|
||||
|
||||
|
||||
|
||||
After installation of above required libraries for snort, again run the configure scripts without any error.
|
||||
|
||||
Run make & make install commands for the compilation and installations of snort in /usr/local/snort directory.
|
||||
|
||||
#make
|
||||
|
||||
|
||||
|
||||
#make install
|
||||
|
||||
|
||||
|
||||
Finally snort running from /usr/local/snort/bin directory. Currently it is in promisc mode (packet dump mode) of all traffic on eth0 interface.
|
||||
|
||||
|
||||
|
||||
Traffic dump by the snort interface is shown in following figure.
|
||||
|
||||
|
||||
|
||||
#### Rules and Configuration of Snort ####
|
||||
|
||||
Snort installation from source code required rules and configuration setting therefore now we will copy rules and configuration under /etc/snort directory. We have created single bash scripts for rules and configuration setting. It is used for following snort setting.
|
||||
|
||||
- Creation of snort user for snort IDS service on linux.
|
||||
- Creation of directories and files under /etc directory for snort configuration.
|
||||
- Permission setting and copying data from etc directory of snort source code.
|
||||
- Remove # (comment sign) from rules path in snort.conf file.
|
||||
|
||||
#!/bin/bash##PATH of source code of snort
|
||||
snort_src="/home/test/Downloads/snort-2.9.7.3"
|
||||
echo "adding group and user for snort..."
|
||||
groupadd snort &> /dev/null
|
||||
useradd snort -r -s /sbin/nologin -d /var/log/snort -c snort_idps -g snort &> /dev/null#snort configuration
|
||||
echo "Configuring snort..."mkdir -p /etc/snort
|
||||
mkdir -p /etc/snort/rules
|
||||
touch /etc/snort/rules/black_list.rules
|
||||
touch /etc/snort/rules/white_list.rules
|
||||
touch /etc/snort/rules/local.rules
|
||||
mkdir /etc/snort/preproc_rules
|
||||
mkdir /var/log/snort
|
||||
mkdir -p /usr/local/lib/snort_dynamicrules
|
||||
chmod -R 775 /etc/snort
|
||||
chmod -R 775 /var/log/snort
|
||||
chmod -R 775 /usr/local/lib/snort_dynamicrules
|
||||
chown -R snort:snort /etc/snort
|
||||
chown -R snort:snort /var/log/snort
|
||||
chown -R snort:snort /usr/local/lib/snort_dynamicrules
|
||||
###copy configuration and rules from etc directory under source code of snort
|
||||
echo "copying from snort source to /etc/snort ....."
|
||||
echo $snort_src
|
||||
echo "-------------"
|
||||
cp $snort_src/etc/*.conf* /etc/snort
|
||||
cp $snort_src/etc/*.map /etc/snort##enable rules
|
||||
sed -i 's/include \$RULE\_PATH/#include \$RULE\_PATH/' /etc/snort/snort.conf
|
||||
echo "---DONE---"
|
||||
|
||||
Change the snort source directory in the script and run it. Following output appear in case of success.
|
||||
|
||||
|
||||
|
||||
Above script copied following files/directories from snort source into /etc/snort configuration file.
|
||||
|
||||
|
||||
|
||||
Snort configuration file is very complex however following necessary changes are required in snort.conf for IDS proper working.
|
||||
|
||||
ipvar HOME_NET 192.168.1.0/24 # LAN side
|
||||
|
||||
----------
|
||||
|
||||
ipvar EXTERNAL_NET !$HOME_NET # WAN side
|
||||
|
||||
|
||||
|
||||
var RULE_PATH /etc/snort/rules # snort signature path
|
||||
var SO_RULE_PATH /etc/snort/so_rules #rules in shared libraries
|
||||
var PREPROC_RULE_PATH /etc/snort/preproc_rules # Preproces path
|
||||
var WHITE_LIST_PATH /etc/snort/rules # dont scan
|
||||
var BLACK_LIST_PATH /etc/snort/rules # Must scan
|
||||
|
||||
|
||||
|
||||
include $RULE_PATH/local.rules # file for custom rules
|
||||
|
||||
remove comment sign (#) from other rules such as ftp.rules,exploit.rules etc.
|
||||
|
||||
|
||||
|
||||
Now [Download community][1] rules and extract under /etc/snort/rules directory. Enable community and emerging threats rules in snort.conf file.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Run following command to test the configuration file after above mentioned changes.
|
||||
|
||||
#snort -T -c /etc/snort/snort.conf
|
||||
|
||||
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
In this article our focus was on the installation and configuration of an open source IDPS system snort on Ubuntu distribution. By default it is used for the monitoring of events however it can con configured inline mode for the protection of network. Snort rules can be tested and analysed in offline mode using pcap capture file.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://linoxide.com/security/install-snort-usage-ubuntu-15-04/
|
||||
|
||||
作者：[nido][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linoxide.com/author/naveeda/
|
||||
[1]:https://www.snort.org/downloads/community/community-rules.tar.gz
|
||||
@ -0,0 +1,143 @@
|
||||
Linux Tricks: Play Game in Chrome, Text-to-Speech, Schedule a Job and Watch Commands in Linux
|
||||
================================================================================
|
||||
Here again, I have compiled a list of four things under [Linux Tips and Tricks][1] series you may do to remain more productive and entertained with Linux Environment.
|
||||
|
||||
|
||||
|
||||
Linux Tips and Tricks Series
|
||||
|
||||
The topics I have covered includes Google-chrome inbuilt small game, Text-to-speech in Linux Terminal, Quick job scheduling using ‘at‘ command and watch a command at regular interval.
|
||||
|
||||
### 1. Play A Game in Google Chrome Browser ###
|
||||
|
||||
Very often when there is a power shedding or no network due to some other reason, I don’t put my Linux box into maintenance mode. I keep myself engage in a little fun game by Google Chrome. I am not a gamer and hence I have not installed third-party creepy games. Security is another concern.
|
||||
|
||||
So when there is Internet related issue and my web page seems something like this:
|
||||
|
||||
|
||||
|
||||
Unable to Connect Internet
|
||||
|
||||
You may play the Google-chrome inbuilt game simply by hitting the space-bar. There is no limitation for the number of times you can play. The best thing is you need not break a sweat installing and using it.
|
||||
|
||||
No third-party application/plugin required. It should work well on other platforms like Windows and Mac but our niche is Linux and I’ll talk about Linux only and mind it, it works well on Linux. It is a very simple game (a kind of time pass).
|
||||
|
||||
Use Space-Bar/Navigation-up-key to jump. A glimpse of the game in action.
|
||||
|
||||
|
||||
|
||||
Play Game in Google Chrome
|
||||
|
||||
### 2. Text to Speech in Linux Terminal ###
|
||||
|
||||
For those who may not be aware of espeak utility, It is a Linux command-line text to speech converter. Write anything in a variety of languages and espeak utility will read it loud for you.
|
||||
|
||||
Espeak should be installed in your system by default, however it is not installed for your system, you may do:
|
||||
|
||||
# apt-get install espeak (Debian)
|
||||
# yum install espeak (CentOS)
|
||||
# dnf install espeak (Fedora 22 onwards)
|
||||
|
||||
You may ask espeak to accept Input Interactively from standard Input device and convert it to speech for you. You may do:
|
||||
|
||||
$ espeak [Hit Return Key]
|
||||
|
||||
For detailed output you may do:
|
||||
|
||||
$ espeak --stdout | aplay [Hit Return Key][Double - Here]
|
||||
|
||||
espeak is flexible and you can ask espeak to accept input from a text file and speak it loud for you. All you need to do is:
|
||||
|
||||
$ espeak --stdout /path/to/text/file/file_name.txt | aplay [Hit Enter]
|
||||
|
||||
You may ask espeak to speak fast/slow for you. The default speed is 160 words per minute. Define your preference using switch ‘-s’.
|
||||
|
||||
To ask espeak to speak 30 words per minute, you may do:
|
||||
|
||||
$ espeak -s 30 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
To ask espeak to speak 200 words per minute, you may do:
|
||||
|
||||
$ espeak -s 200 -f /path/to/text/file/file_name.txt | aplay
|
||||
|
||||
To use another language say Hindi (my mother tongue), you may do:
|
||||
|
||||
$ espeak -v hindi --stdout 'टेकमिंट विश्व की एक बेहतरीन लाइंक्स आधारित वेबसाइट है|' | aplay
|
||||
|
||||
You may choose any language of your preference and ask to speak in your preferred language as suggested above. To get the list of all the languages supported by espeak, you need to run:
|
||||
|
||||
$ espeak --voices
|
||||
|
||||
### 3. Quick Schedule a Job ###
|
||||
|
||||
Most of us are already familiar with [cron][2] which is a daemon to execute scheduled commands.
|
||||
|
||||
Cron is an advanced command often used by Linux SYSAdmins to schedule a job such as Backup or practically anything at certain time/interval.
|
||||
|
||||
Are you aware of ‘at’ command in Linux which lets you schedule a job/command to run at specific time? You can tell ‘at’ what to do and when to do and everything else will be taken care by command ‘at’.
|
||||
|
||||
For an example, say you want to print the output of uptime command at 11:02 AM, All you need to do is:
|
||||
|
||||
$ at 11:02
|
||||
uptime >> /home/$USER/uptime.txt
|
||||
Ctrl+D
|
||||
|
||||
|
||||
|
||||
Schedule Job in Linux
|
||||
|
||||
To check if the command/script/job has been set or not by ‘at’ command, you may do:
|
||||
|
||||
$ at -l
|
||||
|
||||
|
||||
|
||||
View Scheduled Jobs
|
||||
|
||||
You may schedule more than one command in one go using at, simply as:
|
||||
|
||||
$ at 12:30
|
||||
Command – 1
|
||||
Command – 2
|
||||
…
|
||||
command – 50
|
||||
…
|
||||
Ctrl + D
|
||||
|
||||
### 4. Watch a Command at Specific Interval ###
|
||||
|
||||
We need to run some command for specified amount of time at regular interval. Just for example say we need to print the current time and watch the output every 3 seconds.
|
||||
|
||||
To see current time we need to run the below command in terminal.
|
||||
|
||||
$ date +"%H:%M:%S
|
||||
|
||||
|
||||
|
||||
Check Date and Time in Linux
|
||||
|
||||
and to check the output of this command every three seconds, we need to run the below command in Terminal.
|
||||
|
||||
$ watch -n 3 'date +"%H:%M:%S"'
|
||||
|
||||
|
||||
|
||||
Watch Command in Linux
|
||||
|
||||
The switch ‘-n’ in watch command is for Interval. In the above example we defined Interval to be 3 sec. You may define yours as required. Also you may pass any command/script with watch command to watch that command/script at the defined interval.
|
||||
|
||||
That’s all for now. Hope you are like this series that aims at making you more productive with Linux and that too with fun inside. All the suggestions are welcome in the comments below. Stay tuned for more such posts. Keep connected and Enjoy…
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/text-to-speech-in-terminal-schedule-a-job-and-watch-commands-in-linux/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/tag/linux-tricks/
|
||||
[2]:http://www.tecmint.com/11-cron-scheduling-task-examples-in-linux/
|
||||
138
sources/tech/20150813 How to Install Logwatch on Ubuntu 15.04.md
Normal file
138
sources/tech/20150813 How to Install Logwatch on Ubuntu 15.04.md
Normal file
@ -0,0 +1,138 @@
|
||||
(translating by runningwater)
|
||||
How to Install Logwatch on Ubuntu 15.04
|
||||
================================================================================
|
||||
Hi, Today we are going to illustrate the setup of Logwatch on Ubuntu 15.04 Operating system where as it can be used for any Linux and UNIX like operating systems. Logwatch is a customizable system log analyzer and reporting log-monitoring system that go through your logs for a given period of time and make a report in the areas that you wish with the details you want. Its an easy tool to install, configure, review and to take actions that will improve security from data it provides. Logwatch scans the log files of major operating system components, like SSH, Web Server and forwards a summary that contains the valuable items in it that needs to be looked at.
|
||||
|
||||
### Pre-installation Setup ###
|
||||
|
||||
We will be using Ubuntu 15.04 operating system to deploy Logwatch on it so as a perquisite for the installation of Logwatch, make sure that your emails setup is working as it will be used to send email to the administrators for daily reports on the gathered reports.Your system repositories should be enabled as we will be installing it from its available universal repositories.
|
||||
|
||||
Then open the terminal of your ubuntu operating system and login with root user to update your system packages before moving to Logwatch installation.
|
||||
|
||||
root@ubuntu-15:~# apt-get update
|
||||
|
||||
### Installing Logwatch ###
|
||||
|
||||
Once your system is updated and your have fulfilled all its prerequisites then run the following command to start the installation of Logwatch in your server.
|
||||
|
||||
root@ubuntu-15:~# apt-get install logwatch
|
||||
|
||||
The logwatch installation process will starts with addition of some extra required packages as shown once you press “Y” to accept the required changes to the system.
|
||||
|
||||
During the installation process you will be prompted to configure the Postfix Configurations according to your mail server’s setup. Here we used “Local only” in the tutorial for ease, we can choose from the other available options as per your infrastructure requirements and then press “OK” to proceed.
|
||||
|
||||
|
||||
|
||||
Then you have to choose your mail server’s name that will also be used by other programs, so it should be single fully qualified domain name (FQDN).
|
||||
|
||||
|
||||
|
||||
Once you press “OK” after postfix configurations, then it will completes the Logwatch installation process with default configurations of Postfix.
|
||||
|
||||
|
||||
|
||||
You can check the status of Logwatch by issuing the following command in the terminal that should be in active state.
|
||||
|
||||
root@ubuntu-15:~# service postfix status
|
||||
|
||||
|
||||
|
||||
To confirm the installation of Logwatch with its default configurations, issue the simple “logwatch” command as shown.
|
||||
|
||||
root@ubuntu-15:~# logwatch
|
||||
|
||||
The output from the above executed command will results in following compiled report form in the terminal.
|
||||
|
||||
|
||||
|
||||
### Logwatch Configurations ###
|
||||
|
||||
Now after successful installation of Logwatch, we need to make few configuration changes in its configuration file located under following shown path. So, let’s open it with the file editor to update its configurations as required.
|
||||
|
||||
root@ubuntu-15:~# vim /usr/share/logwatch/default.conf/logwatch.conf
|
||||
|
||||
**Output/Format Options**
|
||||
|
||||
By default Logwatch will print to stdout in text with no encoding.To make email Default set “Output = mail” and to save to file set “Output = file”. So you can comment out the its default configurations as per your required settings.
|
||||
|
||||
Output = stdout
|
||||
|
||||
To make Html the default formatting update the following line if you are using Internet email configurations.
|
||||
|
||||
Format = text
|
||||
|
||||
Now add the default person to mail reports should be sent to, it could be a local account or a complete email address that you are free to mention in this line
|
||||
|
||||
MailTo = root
|
||||
#MailTo = user@test.com
|
||||
|
||||
Default person to mail reports sent from can be a local account or any other you wish to use.
|
||||
|
||||
# complete email address.
|
||||
MailFrom = Logwatch
|
||||
|
||||
Save the changes made in the configuration file of Logwatch while leaving the other parameter as default.
|
||||
|
||||
**Cronjob Configuration**
|
||||
|
||||
Now edit the "00logwatch" file in daily crons directory to configure your desired email address to forward reports from logwatch.
|
||||
|
||||
root@ubuntu-15:~# vim /etc/cron.daily/00logwatch
|
||||
|
||||
Here you need to use "--mailto" user@test.com instead of --output mail and save the file.
|
||||
|
||||
|
||||
|
||||
### Using Logwatch Report ###
|
||||
|
||||
Now we generate the test report by executing the "logwatch" command in the terminal to get its result shown in the Text format within the terminal.
|
||||
|
||||
root@ubuntu-15:~#logwatch
|
||||
|
||||
The generated report starts with showing its execution time and date, it will be comprising of different sections that starts with its begin status and closed with end status after showing the complete information about its logs of the mentioned sections.
|
||||
|
||||
Here is its starting point looks like, where it starts by showing all the installed packages in the system as shown below.
|
||||
|
||||
|
||||
|
||||
The following sections shows the logs informmation about the login sessions, rsyslogs and SSH connections about the current and last sessions enabled on the system.
|
||||
|
||||
|
||||
|
||||
The logwatch report will ends up by showing the secure sudo logs and the disk space usage of the root diretory as shown below.
|
||||
|
||||
|
||||
|
||||
You can also check for the generated emails about the logwatch reports by opening the following file.
|
||||
|
||||
root@ubuntu-15:~# vim /var/mail/root
|
||||
|
||||
Here you will be able to see all the generated emails to your configured users with their message delivery status.
|
||||
|
||||
### More about Logwatch ###
|
||||
|
||||
Logwatch is a great tool to lern more about it, so if your more interested to learn more about its logwatch then you can also get much help from the below few commands.
|
||||
|
||||
root@ubuntu-15:~# man logwatch
|
||||
|
||||
The above command contains all the users manual about the logwatch, so read it carefully and to exit from the manuals section simply press "q".
|
||||
|
||||
To get help about the logwatch commands usage you can run the following help command for further information in details.
|
||||
|
||||
root@ubuntu-15:~# logwatch --help
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
At the end of this tutorial you learn about the complete setup of Logwatch on Ubuntu 15.04 that includes with its installation and configurations guide. Now you can start monitoring your logs in a customize able form, whether you monitor the logs of all the services rnning on your system or you customize it to send you the reports about the specific services on the scheduled days. So, let's use this tool and feel free to leave us a comment if you face any issue or need to know more about logwatch usage.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://linoxide.com/ubuntu-how-to/install-use-logwatch-ubuntu-15-04/
|
||||
|
||||
作者：[Kashif Siddique][a]
|
||||
译者：[runningwater](https://github.com/runningwater)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linoxide.com/author/kashifs/
|
||||
@ -0,0 +1,68 @@
|
||||
How to get Public IP from Linux Terminal?
|
||||
================================================================================
|
||||
|
||||
|
||||
Public addresses are assigned by InterNIC and consist of class-based network IDs or blocks of CIDR-based addresses (called CIDR blocks) that are guaranteed to be globally unique to the Internet. How to get Public IP from Linux Terminal - blackMORE OpsWhen the public addresses are assigned, routes are programmed into the routers of the Internet so that traffic to the assigned public addresses can reach their locations. Traffic to destination public addresses are reachable on the Internet. For example, when an organization is assigned a CIDR block in the form of a network ID and subnet mask, that [network ID, subnet mask] pair also exists as a route in the routers of the Internet. IP packets destined to an address within the CIDR block are routed to the proper destination. In this post I will show several ways to find your public IP address from Linux terminal. This though seems like a waste for normal users, but when you are in a terminal of a headless Linux server(i.e. no GUI or you’re connected as a user with minimal tools). Either way, being able to getHow to get Public IP from Linux Terminal public IP from Linux terminal can be useful in many cases or it could be one of those things that might just come in handy someday.
|
||||
|
||||
There’s two main commands we use, curl and wget. You can use them interchangeably.
|
||||
|
||||
### Curl output in plain text format: ###
|
||||
|
||||
curl icanhazip.com
|
||||
curl ifconfig.me
|
||||
curl curlmyip.com
|
||||
curl ip.appspot.com
|
||||
curl ipinfo.io/ip
|
||||
curl ipecho.net/plain
|
||||
curl www.trackip.net/i
|
||||
|
||||
### curl output in JSON format: ###
|
||||
|
||||
curl ipinfo.io/json
|
||||
curl ifconfig.me/all.json
|
||||
curl www.trackip.net/ip?json (bit ugly)
|
||||
|
||||
### curl output in XML format: ###
|
||||
|
||||
curl ifconfig.me/all.xml
|
||||
|
||||
### curl all IP details – The motherload ###
|
||||
|
||||
curl ifconfig.me/all
|
||||
|
||||
### Using DYNDNS (Useful when you’re using DYNDNS service) ###
|
||||
|
||||
curl -s 'http://checkip.dyndns.org' | sed 's/.*Current IP Address: \([0-9\.]*\).*/\1/g'
|
||||
curl -s http://checkip.dyndns.org/ | grep -o "[[:digit:].]\+"
|
||||
|
||||
### Using wget instead of curl ###
|
||||
|
||||
wget http://ipecho.net/plain -O - -q ; echo
|
||||
wget http://observebox.com/ip -O - -q ; echo
|
||||
|
||||
### Using host and dig command (cause we can) ###
|
||||
|
||||
You can also use host and dig command assuming they are available or installed
|
||||
|
||||
host -t a dartsclink.com | sed 's/.*has address //'
|
||||
dig +short myip.opendns.com @resolver1.opendns.com
|
||||
|
||||
### Sample bash script: ###
|
||||
|
||||
#!/bin/bash
|
||||
|
||||
PUBLIC_IP=`wget http://ipecho.net/plain -O - -q ; echo`
|
||||
echo $PUBLIC_IP
|
||||
|
||||
Quite a few to pick from.
|
||||
|
||||
I was actually writing a small script to track all the IP changes of my router each day and save those into a file. I found these nifty commands and sites to use while doing some online research. Hope they help someone else someday too. Thanks for reading, please Share and RT.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.blackmoreops.com/2015/06/14/how-to-get-public-ip-from-linux-terminal/
|
||||
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
@ -0,0 +1,102 @@
|
||||
Howto Run JBoss Data Virtualization GA with OData in Docker Container
|
||||
================================================================================
|
||||
Hi everyone, today we'll learn how to run JBoss Data Virtualization 6.0.0.GA with OData in a Docker Container. JBoss Data Virtualization is a data supply and integration solution platform that transforms various scatered multiple sources data, treats them as single source and delivers the required data into actionable information at business speed to any applications or users. JBoss Data Virtualization can help us easily combine and transform data into reusable business friendly data models and make unified data easily consumable through open standard interfaces. It offers comprehensive data abstraction, federation, integration, transformation, and delivery capabilities to combine data from one or multiple sources into reusable for agile data utilization and sharing.For more information about JBoss Data Virtualization, we can check out [its official page][1]. Docker is an open source platform that provides an open platform to pack, ship and run any application as a lightweight container. Running JBoss Data Virtualization with OData in Docker Container makes us easy to handle and launch.
|
||||
|
||||
Here are some easy to follow tutorial on how we can run JBoss Data Virtualization with OData in Docker Container.
|
||||
|
||||
### 1. Cloning the Repository ###
|
||||
|
||||
First of all, we'll wanna clone the repository of OData with Data Virtualization ie [https://github.com/jbossdemocentral/dv-odata-docker-integration-demo][2] using git command. As we have an Ubuntu 15.04 distribution of linux running in our machine. We'll need to install git initially using apt-get command.
|
||||
|
||||
# apt-get install git
|
||||
|
||||
Then after installing git, we'll wanna clone the repository by running the command below.
|
||||
|
||||
# git clone https://github.com/jbossdemocentral/dv-odata-docker-integration-demo
|
||||
|
||||
Cloning into 'dv-odata-docker-integration-demo'...
|
||||
remote: Counting objects: 96, done.
|
||||
remote: Total 96 (delta 0), reused 0 (delta 0), pack-reused 96
|
||||
Unpacking objects: 100% (96/96), done.
|
||||
Checking connectivity... done.
|
||||
|
||||
### 2. Downloading JBoss Data Virtualization Installer ###
|
||||
|
||||
Now, we'll need to download JBoss Data Virtualization Installer from the Download Page ie [http://www.jboss.org/products/datavirt/download/][3] . After we download **jboss-dv-installer-6.0.0.GA-redhat-4.jar**, we'll need to keep it under the directory named **software**.
|
||||
|
||||
### 3. Building the Docker Image ###
|
||||
|
||||
Next, after we have downloaded the JBoss Data Virtualization installer, we'll then go for building the docker image using the Dockerfile and its resources we had just cloned from the repository.
|
||||
|
||||
# cd dv-odata-docker-integration-demo/
|
||||
# docker build -t jbossdv600 .
|
||||
|
||||
...
|
||||
Step 22 : USER jboss
|
||||
---> Running in 129f701febd0
|
||||
---> 342941381e37
|
||||
Removing intermediate container 129f701febd0
|
||||
Step 23 : EXPOSE 8080 9990 31000
|
||||
---> Running in 61e6d2c26081
|
||||
---> 351159bb6280
|
||||
Removing intermediate container 61e6d2c26081
|
||||
Step 24 : CMD $JBOSS_HOME/bin/standalone.sh -c standalone.xml -b 0.0.0.0 -bmanagement 0.0.0.0
|
||||
---> Running in a9fed69b3000
|
||||
---> 407053dc470e
|
||||
Removing intermediate container a9fed69b3000
|
||||
Successfully built 407053dc470e
|
||||
|
||||
Note: Here, we assume that you have already installed docker and is running in your machine.
|
||||
|
||||
### 4. Starting the Docker Container ###
|
||||
|
||||
As we have built the Docker Image of JBoss Data Virtualization with oData, we'll now gonna run the docker container and expose its port with -P flag. To do so, we'll run the following command.
|
||||
|
||||
# docker run -p 8080:8080 -d -t jbossdv600
|
||||
|
||||
7765dee9cd59c49ca26850e88f97c21f46859d2dc1d74166353d898773214c9c
|
||||
|
||||
### 5. Getting the Container IP ###
|
||||
|
||||
After we have started the Docker Container, we'll wanna get the IP address of the running docker container. To do so, we'll run the docker inspect command followed by the running container id.
|
||||
|
||||
# docker inspect <$containerID>
|
||||
|
||||
...
|
||||
"NetworkSettings": {
|
||||
"Bridge": "",
|
||||
"EndpointID": "3e94c5900ac5954354a89591a8740ce2c653efde9232876bc94878e891564b39",
|
||||
"Gateway": "172.17.42.1",
|
||||
"GlobalIPv6Address": "",
|
||||
"GlobalIPv6PrefixLen": 0,
|
||||
"HairpinMode": false,
|
||||
"IPAddress": "172.17.0.8",
|
||||
"IPPrefixLen": 16,
|
||||
"IPv6Gateway": "",
|
||||
"LinkLocalIPv6Address": "",
|
||||
"LinkLocalIPv6PrefixLen": 0,
|
||||
|
||||
### 6. Web Interface ###
|
||||
|
||||
Now, if everything went as expected as done above, we'll gonna see the login screen of JBoss Data Virtualization with oData when pointing our web browser to http://container-ip:8080/ and the JBoss Management from http://container-ip:9990. The Management credentials for username is admin and password is redhat1! whereas the Data virtualization credentials for username is user and password is user . After that, we can navigate the contents via the web interface.
|
||||
|
||||
**Note**: It is strongly recommended to change the password as soon as possible after the first login. Thanks :)
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
Finally we've successfully run Docker Container running JBoss Data Virtualization with OData Multisource Virtual Database. JBoss Data Virtualization is really an awesome platform for the virtualization of data from different multiple source and transform them into reusable business friendly data models and produces data easily consumable through open standard interfaces. The deployment of JBoss Data Virtualization with OData Multisource Virtual Database has been very easy, secure and fast to setup with the Docker Technology. If you have any questions, suggestions, feedback please write them in the comment box below so that we can improve or update our contents. Thank you ! Enjoy :-)
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://linoxide.com/linux-how-to/run-jboss-data-virtualization-ga-odata-docker-container/
|
||||
|
||||
作者：[Arun Pyasi][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linoxide.com/author/arunp/
|
||||
[1]:http://www.redhat.com/en/technologies/jboss-middleware/data-virtualization
|
||||
[2]:https://github.com/jbossdemocentral/dv-odata-docker-integration-demo
|
||||
[3]:http://www.jboss.org/products/datavirt/download/
|
||||
@ -0,0 +1,164 @@
|
||||
DongShuaike is translating.
|
||||
|
||||
Linux and Unix Test Disk I/O Performance With dd Command
|
||||
================================================================================
|
||||
How can I use dd command on a Linux to test I/O performance of my hard disk drive? How do I check the performance of a hard drive including the read and write speed on a Linux operating systems?
|
||||
|
||||
You can use the following commands on a Linux or Unix-like systems for simple I/O performance test:
|
||||
|
||||
- **dd command** : It is used to monitor the writing performance of a disk device on a Linux and Unix-like system
|
||||
- **hdparm command** : It is used to get/set hard disk parameters including test the reading and caching performance of a disk device on a Linux based system.
|
||||
|
||||
In this tutorial you will learn how to use the dd command to test disk I/O performance.
|
||||
|
||||
### Use dd command to monitor the reading and writing performance of a disk device: ###
|
||||
|
||||
- Open a shell prompt.
|
||||
- Or login to a remote server via ssh.
|
||||
- Use the dd command to measure server throughput (write speed) `dd if=/dev/zero of=/tmp/test1.img bs=1G count=1 oflag=dsync`
|
||||
- Use the dd command to measure server latency `dd if=/dev/zero of=/tmp/test2.img bs=512 count=1000 oflag=dsync`
|
||||
|
||||
#### Understanding dd command options ####
|
||||
|
||||
In this example, I'm using RAID-10 (Adaptec 5405Z with SAS SSD) array running on a Ubuntu Linux 14.04 LTS server. The basic syntax is
|
||||
|
||||
dd if=/dev/input.file of=/path/to/output.file bs=block-size count=number-of-blocks oflag=dsync
|
||||
## GNU dd syntax ##
|
||||
dd if=/dev/zero of=/tmp/test1.img bs=1G count=1 oflag=dsync
|
||||
## OR alternate syntax for GNU/dd ##
|
||||
dd if=/dev/zero of=/tmp/testALT.img bs=1G count=1 conv=fdatasync
|
||||
|
||||
Sample outputs:
|
||||
|
||||
|
||||
Fig.01: Ubuntu Linux Server with RAID10 and testing server throughput with dd
|
||||
|
||||
Please note that one gigabyte was written for the test and 135 MB/s was server throughput for this test. Where,
|
||||
|
||||
- `if=/dev/zero (if=/dev/input.file)` : The name of the input file you want dd the read from.
|
||||
- `of=/tmp/test1.img (of=/path/to/output.file)` : The name of the output file you want dd write the input.file to.
|
||||
- `bs=1G (bs=block-size)` : Set the size of the block you want dd to use. 1 gigabyte was written for the test.
|
||||
- `count=1 (count=number-of-blocks)`: The number of blocks you want dd to read.
|
||||
- `oflag=dsync (oflag=dsync)` : Use synchronized I/O for data. Do not skip this option. This option get rid of caching and gives you good and accurate results
|
||||
- `conv=fdatasyn`: Again, this tells dd to require a complete "sync" once, right before it exits. This option is equivalent to oflag=dsync.
|
||||
|
||||
In this example, 512 bytes were written one thousand times to get RAID10 server latency time:
|
||||
|
||||
dd if=/dev/zero of=/tmp/test2.img bs=512 count=1000 oflag=dsync
|
||||
|
||||
Sample outputs:
|
||||
|
||||
1000+0 records in
|
||||
1000+0 records out
|
||||
512000 bytes (512 kB) copied, 0.60362 s, 848 kB/s
|
||||
|
||||
Please note that server throughput and latency time depends upon server/application load too. So I recommend that you run these tests on a newly rebooted server as well as peak time to get better idea about your workload. You can now compare these numbers with all your devices.
|
||||
|
||||
#### But why the server throughput and latency time are so low? ####
|
||||
|
||||
Low values does not mean you are using slow hardware. The value can be low because of the HARDWARE RAID10 controller's cache.
|
||||
|
||||
Use hdparm command to see buffered and cached disk read speed
|
||||
|
||||
I suggest you run the following commands 2 or 3 times Perform timings of device reads for benchmark and comparison purposes:
|
||||
|
||||
### Buffered disk read test for /dev/sda ##
|
||||
hdparm -t /dev/sda1
|
||||
## OR ##
|
||||
hdparm -t /dev/sda
|
||||
|
||||
To perform timings of cache reads for benchmark and comparison purposes again run the following command 2-3 times (note the -T option):
|
||||
|
||||
## Cache read benchmark for /dev/sda ###
|
||||
hdparm -T /dev/sda1
|
||||
## OR ##
|
||||
hdparm -T /dev/sda
|
||||
|
||||
OR combine both tests:
|
||||
|
||||
hdparm -Tt /dev/sda
|
||||
|
||||
Sample outputs:
|
||||
|
||||
|
||||
Fig.02: Linux hdparm command to test reading and caching disk performance
|
||||
|
||||
Again note that due to filesystems caching on file operations, you will always see high read rates.
|
||||
|
||||
**Use dd command on Linux to test read speed**
|
||||
|
||||
To get accurate read test data, first discard caches before testing by running the following commands:
|
||||
|
||||
flush
|
||||
echo 3 | sudo tee /proc/sys/vm/drop_caches
|
||||
time time dd if=/path/to/bigfile of=/dev/null bs=8k
|
||||
|
||||
**Linux Laptop example**
|
||||
|
||||
Run the following command:
|
||||
|
||||
### Debian Laptop Throughput With Cache ##
|
||||
dd if=/dev/zero of=/tmp/laptop.bin bs=1G count=1 oflag=direct
|
||||
|
||||
### Deactivate the cache ###
|
||||
hdparm -W0 /dev/sda
|
||||
|
||||
### Debian Laptop Throughput Without Cache ##
|
||||
dd if=/dev/zero of=/tmp/laptop.bin bs=1G count=1 oflag=direct
|
||||
|
||||
**Apple OS X Unix (Macbook pro) example**
|
||||
|
||||
GNU dd has many more options but OS X/BSD and Unix-like dd command need to run as follows to test real disk I/O and not memory add sync option as follows:
|
||||
|
||||
## Run command 2-3 times to get good results ###
|
||||
time sh -c "dd if=/dev/zero of=/tmp/testfile bs=100k count=1k && sync"
|
||||
|
||||
Sample outputs:
|
||||
|
||||
1024+0 records in
|
||||
1024+0 records out
|
||||
104857600 bytes transferred in 0.165040 secs (635346520 bytes/sec)
|
||||
|
||||
real 0m0.241s
|
||||
user 0m0.004s
|
||||
sys 0m0.113s
|
||||
|
||||
So I'm getting 635346520 bytes (635.347 MB/s) write speed on my MBP.
|
||||
|
||||
**Not a fan of command line...?**
|
||||
|
||||
You can use disk utility (gnome-disk-utility) on a Linux or Unix based system to get the same information. The following screenshot is taken from my Fedora Linux v22 VM.
|
||||
|
||||
**Graphical method**
|
||||
|
||||
Click on the "Activities" or press the "Super" key to switch between the Activities overview and desktop. Type "Disks"
|
||||
|
||||
|
||||
Fig.03: Start the Gnome disk utility
|
||||
|
||||
Select your hard disk at left pane and click on configure button and click on "Benchmark partition":
|
||||
|
||||
|
||||
Fig.04: Benchmark disk/partition
|
||||
|
||||
Finally, click on the "Start Benchmark..." button (you may be promoted for the admin username and password):
|
||||
|
||||
|
||||
Fig.05: Final benchmark result
|
||||
|
||||
Which method and command do you recommend to use?
|
||||
|
||||
- I recommend dd command on all Unix-like systems (`time sh -c "dd if=/dev/zero of=/tmp/testfile bs=100k count=1k && sync`"
|
||||
- If you are using GNU/Linux use the dd command (`dd if=/dev/zero of=/tmp/testALT.img bs=1G count=1 conv=fdatasync`)
|
||||
- Make sure you adjust count and bs arguments as per your setup to get a good set of result.
|
||||
- The GUI method is recommended only for Linux/Unix laptop users running Gnome2 or 3 desktop.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/
|
||||
|
||||
作者：Vivek Gite
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
441
sources/tech/20150813 Linux file system hierarchy v2.0.md
Normal file
441
sources/tech/20150813 Linux file system hierarchy v2.0.md
Normal file
@ -0,0 +1,441 @@
|
||||
|
||||
Translating by dingdongnigetou
|
||||
|
||||
Linux file system hierarchy v2.0
|
||||
================================================================================
|
||||
What is a file in Linux? What is file system in Linux? Where are all the configuration files? Where do I keep my downloaded applications? Is there really a filesystem standard structure in Linux? Well, the above image explains Linux file system hierarchy in a very simple and non-complex way. It’s very useful when you’re looking for a configuration file or a binary file. I’ve added some explanation and examples below, but that’s TL;DR.
|
||||
|
||||
Another issue is when you got configuration and binary files all over the system that creates inconsistency and if you’re a large organization or even an end user, it can compromise your system (binary talking with old lib files etc.) and when you do [security audit of your Linux system][1], you find it is vulnerable to different exploits. So keeping a clean operating system (no matter Windows or Linux) is important.
|
||||
|
||||
### What is a file in Linux? ###
|
||||
|
||||
A simple description of the UNIX system, also applicable to Linux, is this:
|
||||
|
||||
> On a UNIX system, everything is a file; if something is not a file, it is a process.
|
||||
|
||||
This statement is true because there are special files that are more than just files (named pipes and sockets, for instance), but to keep things simple, saying that everything is a file is an acceptable generalization. A Linux system, just like UNIX, makes no difference between a file and a directory, since a directory is just a file containing names of other files. Programs, services, texts, images, and so forth, are all files. Input and output devices, and generally all devices, are considered to be files, according to the system.
|
||||
|
||||
|
||||
|
||||
- Version 2.0 – 17-06-2015
|
||||
- – Improved: Added title and version history.
|
||||
- – Improved: Added /srv, /media and /proc.
|
||||
- – Improved: Updated descriptions to reflect modern Linux File Systems.
|
||||
- – Fixed: Multiple typo’s.
|
||||
- – Fixed: Appearance and colour.
|
||||
- Version 1.0 – 14-02-2015
|
||||
- – Created: Initial diagram.
|
||||
- – Note: Discarded lowercase version.
|
||||
|
||||
### Download Links ###
|
||||
|
||||
Following are two links for download. If you need this in any other format, let me know and I will try to create that and upload it somewhere.
|
||||
|
||||
- [Large (PNG) Format – 2480×1755 px – 184KB][2]
|
||||
- [Largest (PDF) Format – 9919x7019 px – 1686KB][3]
|
||||
|
||||
**Note**: PDF Format is best for printing and very high in quality
|
||||
|
||||
### Linux file system description ###
|
||||
|
||||
In order to manage all those files in an orderly fashion, man likes to think of them in an ordered tree-like structure on the hard disk, as we know from `MS-DOS` (Disk Operating System) for instance. The large branches contain more branches, and the branches at the end contain the tree’s leaves or normal files. For now we will use this image of the tree, but we will find out later why this is not a fully accurate image.
|
||||
|
||||
注：表格
|
||||
<table cellspacing="2" border="4" style="border-collapse: collapse; width: 731px; height: 2617px;">
|
||||
<thead>
|
||||
<tr>
|
||||
<th scope="col">Directory</th>
|
||||
<th scope="col">Description</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/</code></dd>
|
||||
</dl></td>
|
||||
<td><i>Primary hierarchy</i> root and root directory of the entire file system hierarchy.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/bin</code></dd>
|
||||
</dl></td>
|
||||
<td>Essential command binaries that need to be available in single user mode; for all users, <i>e.g.</i>, cat, ls, cp.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/boot</code></dd>
|
||||
</dl></td>
|
||||
<td>Boot loader files, <i>e.g.</i>, kernels, initrd.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/dev</code></dd>
|
||||
</dl></td>
|
||||
<td>Essential devices, <i>e.g.</i>, <code>/dev/null</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/etc</code></dd>
|
||||
</dl></td>
|
||||
<td>Host-specific system-wide configuration filesThere has been controversy over the meaning of the name itself. In early versions of the UNIX Implementation Document from Bell labs, /etc is referred to as the <i>etcetera directory</i>, as this directory historically held everything that did not belong elsewhere (however, the FHS restricts /etc to static configuration files and may not contain binaries). Since the publication of early documentation, the directory name has been re-designated in various ways. Recent interpretations include backronyms such as “Editable Text Configuration” or “Extended Tool Chest”.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/opt</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Configuration files for add-on packages that are stored in <code>/opt/</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/sgml</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Configuration files, such as catalogs, for software that processes SGML.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/X11</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Configuration files for the X Window System, version 11.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/xml</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Configuration files, such as catalogs, for software that processes XML.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/home</code></dd>
|
||||
</dl></td>
|
||||
<td>Users’ home directories, containing saved files, personal settings, etc.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/lib</code></dd>
|
||||
</dl></td>
|
||||
<td>Libraries essential for the binaries in <code>/bin/</code> and <code>/sbin/</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/lib<qual></code></dd>
|
||||
</dl></td>
|
||||
<td>Alternate format essential libraries. Such directories are optional, but if they exist, they have some requirements.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/media</code></dd>
|
||||
</dl></td>
|
||||
<td>Mount points for removable media such as CD-ROMs (appeared in FHS-2.3).</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/mnt</code></dd>
|
||||
</dl></td>
|
||||
<td>Temporarily mounted filesystems.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/opt</code></dd>
|
||||
</dl></td>
|
||||
<td>Optional application software packages.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/proc</code></dd>
|
||||
</dl></td>
|
||||
<td>Virtual filesystem providing process and kernel information as files. In Linux, corresponds to a procfs mount.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/root</code></dd>
|
||||
</dl></td>
|
||||
<td>Home directory for the root user.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/sbin</code></dd>
|
||||
</dl></td>
|
||||
<td>Essential system binaries, <i>e.g.</i>, init, ip, mount.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/srv</code></dd>
|
||||
</dl></td>
|
||||
<td>Site-specific data which are served by the system.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/tmp</code></dd>
|
||||
</dl></td>
|
||||
<td>Temporary files (see also <code>/var/tmp</code>). Often not preserved between system reboots.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/usr</code></dd>
|
||||
</dl></td>
|
||||
<td><i>Secondary hierarchy</i> for read-only user data; contains the majority of (multi-)user utilities and applications.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/bin</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Non-essential command binaries (not needed in single user mode); for all users.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/include</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Standard include files.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/lib</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Libraries for the binaries in <code>/usr/bin/</code> and <code>/usr/sbin/</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/lib<qual></code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Alternate format libraries (optional).</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/local</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td><i>Tertiary hierarchy</i> for local data, specific to this host. Typically has further subdirectories, <i>e.g.</i>, <code>bin/</code>, <code>lib/</code>, <code>share/</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/sbin</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Non-essential system binaries, <i>e.g.</i>, daemons for various network-services.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/share</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Architecture-independent (shared) data.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/src</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Source code, <i>e.g.</i>, the kernel source code with its header files.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/X11R6</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>X Window System, Version 11, Release 6.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd><code>/var</code></dd>
|
||||
</dl></td>
|
||||
<td>Variable files—files whose content is expected to continually change during normal operation of the system—such as logs, spool files, and temporary e-mail files.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/cache</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Application cache data. Such data are locally generated as a result of time-consuming I/O or calculation. The application must be able to regenerate or restore the data. The cached files can be deleted without loss of data.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/lib</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>State information. Persistent data modified by programs as they run, <i>e.g.</i>, databases, packaging system metadata, etc.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/lock</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Lock files. Files keeping track of resources currently in use.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/log</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Log files. Various logs.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/mail</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Users’ mailboxes.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/opt</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Variable data from add-on packages that are stored in <code>/opt/</code>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/run</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Information about the running system since last boot, <i>e.g.</i>, currently logged-in users and running <a href="http://en.wikipedia.org/wiki/Daemon_%28computing%29">daemons</a>.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/spool</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Spool for tasks waiting to be processed, <i>e.g.</i>, print queues and outgoing mail queue.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/mail</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Deprecated location for users’ mailboxes.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><dl>
|
||||
<dd>
|
||||
<dl>
|
||||
<dd><code>/tmp</code></dd>
|
||||
</dl>
|
||||
</dd>
|
||||
</dl></td>
|
||||
<td>Temporary files to be preserved between reboots.</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
|
||||
### Types of files in Linux ###
|
||||
|
||||
Most files are just files, called `regular` files; they contain normal data, for example text files, executable files or programs, input for or output from a program and so on.
|
||||
|
||||
While it is reasonably safe to suppose that everything you encounter on a Linux system is a file, there are some exceptions.
|
||||
|
||||
- `Directories`: files that are lists of other files.
|
||||
- `Special files`: the mechanism used for input and output. Most special files are in `/dev`, we will discuss them later.
|
||||
- `Links`: a system to make a file or directory visible in multiple parts of the system’s file tree. We will talk about links in detail.
|
||||
- `(Domain) sockets`: a special file type, similar to TCP/IP sockets, providing inter-process networking protected by the file system’s access control.
|
||||
- `Named pipes`: act more or less like sockets and form a way for processes to communicate with each other, without using network socket semantics.
|
||||
|
||||
### File system in reality ###
|
||||
|
||||
For most users and for most common system administration tasks, it is enough to accept that files and directories are ordered in a tree-like structure. The computer, however, doesn’t understand a thing about trees or tree-structures.
|
||||
|
||||
Every partition has its own file system. By imagining all those file systems together, we can form an idea of the tree-structure of the entire system, but it is not as simple as that. In a file system, a file is represented by an `inode`, a kind of serial number containing information about the actual data that makes up the file: to whom this file belongs, and where is it located on the hard disk.
|
||||
|
||||
Every partition has its own set of inodes; throughout a system with multiple partitions, files with the same inode number can exist.
|
||||
|
||||
Each inode describes a data structure on the hard disk, storing the properties of a file, including the physical location of the file data. When a hard disk is initialized to accept data storage, usually during the initial system installation process or when adding extra disks to an existing system, a fixed number of inodes per partition is created. This number will be the maximum amount of files, of all types (including directories, special files, links etc.) that can exist at the same time on the partition. We typically count on having 1 inode per 2 to 8 kilobytes of storage.At the time a new file is created, it gets a free inode. In that inode is the following information:
|
||||
|
||||
- Owner and group owner of the file.
|
||||
- File type (regular, directory, …)
|
||||
- Permissions on the file
|
||||
- Date and time of creation, last read and change.
|
||||
- Date and time this information has been changed in the inode.
|
||||
- Number of links to this file (see later in this chapter).
|
||||
- File size
|
||||
- An address defining the actual location of the file data.
|
||||
|
||||
The only information not included in an inode, is the file name and directory. These are stored in the special directory files. By comparing file names and inode numbers, the system can make up a tree-structure that the user understands. Users can display inode numbers using the -i option to ls. The inodes have their own separate space on the disk.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.blackmoreops.com/2015/06/18/linux-file-system-hierarchy-v2-0/
|
||||
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[1]:http://www.blackmoreops.com/2015/02/15/in-light-of-recent-linux-exploits-linux-security-audit-is-a-must/
|
||||
[2]:http://www.blackmoreops.com/wp-content/uploads/2015/06/Linux-file-system-hierarchy-v2.0-2480px-blackMORE-Ops.png
|
||||
[3]:http://www.blackmoreops.com/wp-content/uploads/2015/06/Linux-File-System-Hierarchy-blackMORE-Ops.pdf
|
||||
@ -0,0 +1,63 @@
|
||||
Ubuntu Want To Make It Easier For You To Install The Latest Nvidia Linux Driver
|
||||
================================================================================
|
||||
|
||||
Ubuntu Gamers are on the rise -and so is demand for the latest drivers
|
||||
|
||||
**Installing the latest upstream NVIDIA graphics driver on Ubuntu could be about to get much easier. **
|
||||
|
||||
Ubuntu developers are considering the creation of a brand new ‘official’ PPA to distribute the latest closed-source NVIDIA binary drivers to desktop users.
|
||||
|
||||
The move would benefit Ubuntu gamers **without** risking the stability of the OS for everyone else.
|
||||
|
||||
New upstream drivers would be installed and updated from this new PPA **only** when a user explicitly opts-in to it. Everyone else would continue to receive and use the more recent stable NVIDIA Linux driver snapshot included in the Ubuntu archive.
|
||||
|
||||
### Why Is This Needed? ###
|
||||
|
||||
|
||||
Ubuntu provides drivers – but they’re not the latest
|
||||
|
||||
The closed-source NVIDIA graphics drivers that are available to install on Ubuntu from the archive (using the command line, synaptic or through the additional drivers tool) work fine for most and can handle the composited Unity desktop shell with ease.
|
||||
|
||||
For gaming needs it’s a different story.
|
||||
|
||||
If you want to squeeze every last frame and HD texture out of the latest big-name Steam game you’ll need the latest binary drivers blob.
|
||||
|
||||
> ‘Installing the very latest Nvidia Linux driver on Ubuntu is not easy and not always safe.’
|
||||
|
||||
The more recent the driver the more likely it is to support the latest features and technologies, or come pre-packed with game-specific tweaks and bug fixes too.
|
||||
|
||||
The problem is that installing the very latest Nvidia Linux driver on Ubuntu is not easy and not always safe.
|
||||
|
||||
To fill the void many third-party PPAs maintained by enthusiasts have emerged. Since many of these PPAs also distribute other experimental or bleeding-edge software their use is **not without risk**. Adding a bleeding edge PPA is often the fastest way to entirely hose a system!
|
||||
|
||||
A solution that lets Ubuntu users install the latest propriety graphics drivers as offered in third-party PPAs is needed **but** with the safety catch of being able to roll-back to the stable archive version if needed.
|
||||
|
||||
### ‘Demand for fresh drivers is hard to ignore’ ###
|
||||
|
||||
> ‘A solution that lets Ubuntu users get the latest hardware drivers safely is coming.’
|
||||
|
||||
‘The demand for fresh drivers in a fast developing market is becoming hard to ignore, users are going to want the latest upstream has to offer,’ Castro explains in an e-mail to the Ubuntu Desktop mailing list.
|
||||
|
||||
‘[NVIDIA] can deliver a kickass experience with almost no effort from the user [in Windows 10]. Until we can convince NVIDIA to do the same with Ubuntu we’re going to have to pick up the slack.’
|
||||
|
||||
Castro’s proposition of a “blessed” NVIDIA PPA is the easiest way to do this.
|
||||
|
||||
Gamers would be able to opt-in to receive new drivers from the PPA straight from Ubuntu’s default proprietary hardware drivers tool — no need for them to copy and paste terminal commands from websites or wiki pages.
|
||||
|
||||
The drivers within this PPA would be packaged and maintained by a select band of community members and receive benefits from being a semi-official option, namely **automated testing**.
|
||||
|
||||
As Castro himself puts it: ‘People want the latest bling, and no matter what they’re going to do it. We might as well put a framework around it so people can get what they want without breaking their computer.’
|
||||
|
||||
**Would you make use of this PPA? How would you rate the performance of the default Nvidia drivers on Ubuntu? Share your thoughts in the comments, folks! **
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.omgubuntu.co.uk/2015/08/ubuntu-easy-install-latest-nvidia-linux-drivers
|
||||
|
||||
作者：[Joey-Elijah Sneddon][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:https://plus.google.com/117485690627814051450/?rel=author
|
||||
@ -0,0 +1,228 @@
|
||||
Translating by ictlyh
|
||||
Part 1 - RHCE Series: How to Setup and Test Static Network Routing
|
||||
================================================================================
|
||||
RHCE (Red Hat Certified Engineer) is a certification from Red Hat company, which gives an open source operating system and software to the enterprise community, It also gives training, support and consulting services for the companies.
|
||||
|
||||
|
||||
|
||||
RHCE Exam Preparation Guide
|
||||
|
||||
This RHCE (Red Hat Certified Engineer) is a performance-based exam (codename EX300), who possesses the additional skills, knowledge, and abilities required of a senior system administrator responsible for Red Hat Enterprise Linux (RHEL) systems.
|
||||
|
||||
**Important**: [Red Hat Certified System Administrator][1] (RHCSA) certification is required to earn RHCE certification.
|
||||
|
||||
Following are the exam objectives based on the Red Hat Enterprise Linux 7 version of the exam, which will going to cover in this RHCE series:
|
||||
|
||||
- Part 1: How to Setup and Test Static Routing in RHEL 7
|
||||
- Part 2: How to Perform Packet Filtering, Network Address Translation and Set Kernel Runtime Parameters
|
||||
- Part 3: How to Produce and Deliver System Activity Reports Using Linux Toolsets
|
||||
- Part 4: Automate System Maintenance Tasks Using Shell Scripts
|
||||
- Part 5: How to Configure Local and Remote System Logging
|
||||
- Part 6: How to Configure a Samba Server and a NFS Server
|
||||
- Part 7: Setting Up Complete SMTP Server for Mailing
|
||||
- Part 8: Setting Up HTTPS and TLS on RHEL 7
|
||||
- Part 9: Setting Up Network Time Protocol
|
||||
- Part 10: How to Configure a Cache-Only DNS Server
|
||||
|
||||
To view fees and register for an exam in your country, check the [RHCE Certification][2] page.
|
||||
|
||||
In this Part 1 of the RHCE series and the next, we will present basic, yet typical, cases where the principles of static routing, packet filtering, and network address translation come into play.
|
||||
|
||||
|
||||
|
||||
RHCE: Setup and Test Network Static Routing – Part 1
|
||||
|
||||
Please note that we will not cover them in depth, but rather organize these contents in such a way that will be helpful to take the first steps and build from there.
|
||||
|
||||
### Static Routing in Red Hat Enterprise Linux 7 ###
|
||||
|
||||
One of the wonders of modern networking is the vast availability of devices that can connect groups of computers, whether in relatively small numbers and confined to a single room or several machines in the same building, city, country, or across continents.
|
||||
|
||||
However, in order to effectively accomplish this in any situation, network packets need to be routed, or in other words, the path they follow from source to destination must be ruled somehow.
|
||||
|
||||
Static routing is the process of specifying a route for network packets other than the default, which is provided by a network device known as the default gateway. Unless specified otherwise through static routing, network packets are directed to the default gateway; with static routing, other paths are defined based on predefined criteria, such as the packet destination.
|
||||
|
||||
Let us define the following scenario for this tutorial. We have a Red Hat Enterprise Linux 7 box connecting to router #1 [192.168.0.1] to access the Internet and machines in 192.168.0.0/24.
|
||||
|
||||
A second router (router #2) has two network interface cards: enp0s3 is also connected to router #1 to access the Internet and to communicate with the RHEL 7 box and other machines in the same network, whereas the other (enp0s8) is used to grant access to the 10.0.0.0/24 network where internal services reside, such as a web and / or database server.
|
||||
|
||||
This scenario is illustrated in the diagram below:
|
||||
|
||||
|
||||
|
||||
Static Routing Network Diagram
|
||||
|
||||
In this article we will focus exclusively on setting up the routing table on our RHEL 7 box to make sure that it can both access the Internet through router #1 and the internal network via router #2.
|
||||
|
||||
In RHEL 7, you will use the [ip command][3] to configure and show devices and routing using the command line. These changes can take effect immediately on a running system but since they are not persistent across reboots, we will use ifcfg-enp0sX and route-enp0sX files inside /etc/sysconfig/network-scripts to save our configuration permanently.
|
||||
|
||||
To begin, let’s print our current routing table:
|
||||
|
||||
# ip route show
|
||||
|
||||
|
||||
|
||||
Check Current Routing Table
|
||||
|
||||
From the output above, we can see the following facts:
|
||||
|
||||
- The default gateway’s IP address is 192.168.0.1 and can be accessed via the enp0s3 NIC.
|
||||
- When the system booted up, it enabled the zeroconf route to 169.254.0.0/16 (just in case). In few words, if a machine is set to obtain an IP address through DHCP but fails to do so for some reason, it is automatically assigned an address in this network. Bottom line is, this route will allow us to communicate, also via enp0s3, with other machines who have failed to obtain an IP address from a DHCP server.
|
||||
- Last, but not least, we can communicate with other boxes inside the 192.168.0.0/24 network through enp0s3, whose IP address is 192.168.0.18.
|
||||
|
||||
These are the typical tasks that you would have to perform in such a setting. Unless specified otherwise, the following tasks should be performed in router #2:
|
||||
|
||||
Make sure all NICs have been properly installed:
|
||||
|
||||
# ip link show
|
||||
|
||||
If one of them is down, bring it up:
|
||||
|
||||
# ip link set dev enp0s8 up
|
||||
|
||||
and assign an IP address in the 10.0.0.0/24 network to it:
|
||||
|
||||
# ip addr add 10.0.0.17 dev enp0s8
|
||||
|
||||
Oops! We made a mistake in the IP address. We will have to remove the one we assigned earlier and then add the right one (10.0.0.18):
|
||||
|
||||
# ip addr del 10.0.0.17 dev enp0s8
|
||||
# ip addr add 10.0.0.18 dev enp0s8
|
||||
|
||||
Now, please note that you can only add a route to a destination network through a gateway that is itself already reachable. For that reason, we need to assign an IP address within the 192.168.0.0/24 range to enp0s3 so that our RHEL 7 box can communicate with it:
|
||||
|
||||
# ip addr add 192.168.0.19 dev enp0s3
|
||||
|
||||
Finally, we will need to enable packet forwarding:
|
||||
|
||||
# echo "1" > /proc/sys/net/ipv4/ip_forward
|
||||
|
||||
and stop / disable (just for the time being – until we cover packet filtering in the next article) the firewall:
|
||||
|
||||
# systemctl stop firewalld
|
||||
# systemctl disable firewalld
|
||||
|
||||
Back in our RHEL 7 box (192.168.0.18), let’s configure a route to 10.0.0.0/24 through 192.168.0.19 (enp0s3 in router #2):
|
||||
|
||||
# ip route add 10.0.0.0/24 via 192.168.0.19
|
||||
|
||||
After that, the routing table looks as follows:
|
||||
|
||||
# ip route show
|
||||
|
||||
|
||||
|
||||
Confirm Network Routing Table
|
||||
|
||||
Likewise, add the corresponding route in the machine(s) you’re trying to reach in 10.0.0.0/24:
|
||||
|
||||
# ip route add 192.168.0.0/24 via 10.0.0.18
|
||||
|
||||
You can test for basic connectivity using ping:
|
||||
|
||||
In the RHEL 7 box, run
|
||||
|
||||
# ping -c 4 10.0.0.20
|
||||
|
||||
where 10.0.0.20 is the IP address of a web server in the 10.0.0.0/24 network.
|
||||
|
||||
In the web server (10.0.0.20), run
|
||||
|
||||
# ping -c 192.168.0.18
|
||||
|
||||
where 192.168.0.18 is, as you will recall, the IP address of our RHEL 7 machine.
|
||||
|
||||
Alternatively, we can use [tcpdump][4] (you may need to install it with yum install tcpdump) to check the 2-way communication over TCP between our RHEL 7 box and the web server at 10.0.0.20.
|
||||
|
||||
To do so, let’s start the logging in the first machine with:
|
||||
|
||||
# tcpdump -qnnvvv -i enp0s3 host 10.0.0.20
|
||||
|
||||
and from another terminal in the same system let’s telnet to port 80 in the web server (assuming Apache is listening on that port; otherwise, indicate the right port in the following command):
|
||||
|
||||
# telnet 10.0.0.20 80
|
||||
|
||||
The tcpdump log should look as follows:
|
||||
|
||||
|
||||
|
||||
Check Network Communication between Servers
|
||||
|
||||
Where the connection has been properly initialized, as we can tell by looking at the 2-way communication between our RHEL 7 box (192.168.0.18) and the web server (10.0.0.20).
|
||||
|
||||
Please remember that these changes will go away when you restart the system. If you want to make them persistent, you will need to edit (or create, if they don’t already exist) the following files, in the same systems where we performed the above commands.
|
||||
|
||||
Though not strictly necessary for our test case, you should know that /etc/sysconfig/network contains system-wide network parameters. A typical /etc/sysconfig/network looks as follows:
|
||||
|
||||
# Enable networking on this system?
|
||||
NETWORKING=yes
|
||||
# Hostname. Should match the value in /etc/hostname
|
||||
HOSTNAME=yourhostnamehere
|
||||
# Default gateway
|
||||
GATEWAY=XXX.XXX.XXX.XXX
|
||||
# Device used to connect to default gateway. Replace X with the appropriate number.
|
||||
GATEWAYDEV=enp0sX
|
||||
|
||||
When it comes to setting specific variables and values for each NIC (as we did for router #2), you will have to edit /etc/sysconfig/network-scripts/ifcfg-enp0s3 and /etc/sysconfig/network-scripts/ifcfg-enp0s8.
|
||||
|
||||
Following our case,
|
||||
|
||||
TYPE=Ethernet
|
||||
BOOTPROTO=static
|
||||
IPADDR=192.168.0.19
|
||||
NETMASK=255.255.255.0
|
||||
GATEWAY=192.168.0.1
|
||||
NAME=enp0s3
|
||||
ONBOOT=yes
|
||||
|
||||
and
|
||||
|
||||
TYPE=Ethernet
|
||||
BOOTPROTO=static
|
||||
IPADDR=10.0.0.18
|
||||
NETMASK=255.255.255.0
|
||||
GATEWAY=10.0.0.1
|
||||
NAME=enp0s8
|
||||
ONBOOT=yes
|
||||
|
||||
for enp0s3 and enp0s8, respectively.
|
||||
|
||||
As for routing in our client machine (192.168.0.18), we will need to edit /etc/sysconfig/network-scripts/route-enp0s3:
|
||||
|
||||
10.0.0.0/24 via 192.168.0.19 dev enp0s3
|
||||
|
||||
Now reboot your system and you should see that route in your table.
|
||||
|
||||
### Summary ###
|
||||
|
||||
In this article we have covered the essentials of static routing in Red Hat Enterprise Linux 7. Although scenarios may vary, the case presented here illustrates the required principles and the procedures to perform this task. Before wrapping up, I would like to suggest you to take a look at [Chapter 4][5] of the Securing and Optimizing Linux section in The Linux Documentation Project site for further details on the topics covered here.
|
||||
|
||||
Free ebook on Securing & Optimizing Linux: The Hacking Solution (v.3.0) – This 800+ eBook contains comprehensive collection of Linux security tips and how to use them safely and easily to configure Linux-based applications and services.
|
||||
|
||||
|
||||
|
||||
Linux Security and Optimization Book
|
||||
|
||||
[Download Now][6]
|
||||
|
||||
In the next article we will talk about packet filtering and network address translation to sum up the networking basic skills needed for the RHCE certification.
|
||||
|
||||
As always, we look forward to hearing from you, so feel free to leave your questions, comments, and suggestions using the form below.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/how-to-setup-and-configure-static-network-routing-in-rhel/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/rhcsa-exam-reviewing-essential-commands-system-documentation/
|
||||
[2]:https://www.redhat.com/en/services/certification/rhce
|
||||
[3]:http://www.tecmint.com/ip-command-examples/
|
||||
[4]:http://www.tecmint.com/12-tcpdump-commands-a-network-sniffer-tool/
|
||||
[5]:http://www.tldp.org/LDP/solrhe/Securing-Optimizing-Linux-RH-Edition-v1.3/net-manage.html
|
||||
[6]:http://tecmint.tradepub.com/free/w_opeb01/prgm.cgi
|
||||
@ -0,0 +1,178 @@
|
||||
Translating by ictlyh
|
||||
Part 2 - How to Perform Packet Filtering, Network Address Translation and Set Kernel Runtime Parameters
|
||||
================================================================================
|
||||
As promised in Part 1 (“[Setup Static Network Routing][1]”), in this article (Part 2 of RHCE series) we will begin by introducing the principles of packet filtering and network address translation (NAT) in Red Hat Enterprise Linux 7, before diving into setting runtime kernel parameters to modify the behavior of a running kernel if certain conditions change or needs arise.
|
||||
|
||||
|
||||
|
||||
RHCE: Network Packet Filtering – Part 2
|
||||
|
||||
### Network Packet Filtering in RHEL 7 ###
|
||||
|
||||
When we talk about packet filtering, we refer to a process performed by a firewall in which it reads the header of each data packet that attempts to pass through it. Then, it filters the packet by taking the required action based on rules that have been previously defined by the system administrator.
|
||||
|
||||
As you probably know, beginning with RHEL 7, the default service that manages firewall rules is [firewalld][2]. Like iptables, it talks to the netfilter module in the Linux kernel in order to examine and manipulate network packets. Unlike iptables, updates can take effect immediately without interrupting active connections – you don’t even have to restart the service.
|
||||
|
||||
Another advantage of firewalld is that it allows us to define rules based on pre-configured service names (more on that in a minute).
|
||||
|
||||
In Part 1, we used the following scenario:
|
||||
|
||||
|
||||
|
||||
Static Routing Network Diagram
|
||||
|
||||
However, you will recall that we disabled the firewall on router #2 to simplify the example since we had not covered packet filtering yet. Let’s see now how we can enable incoming packets destined for a specific service or port in the destination.
|
||||
|
||||
First, let’s add a permanent rule to allow inbound traffic in enp0s3 (192.168.0.19) to enp0s8 (10.0.0.18):
|
||||
|
||||
# firewall-cmd --permanent --direct --add-rule ipv4 filter FORWARD 0 -i enp0s3 -o enp0s8 -j ACCEPT
|
||||
|
||||
The above command will save the rule to /etc/firewalld/direct.xml:
|
||||
|
||||
# cat /etc/firewalld/direct.xml
|
||||
|
||||
|
||||
|
||||
Check Firewalld Saved Rules
|
||||
|
||||
Then enable the rule for it to take effect immediately:
|
||||
|
||||
# firewall-cmd --direct --add-rule ipv4 filter FORWARD 0 -i enp0s3 -o enp0s8 -j ACCEPT
|
||||
|
||||
Now you can telnet to the web server from the RHEL 7 box and run [tcpdump][3] again to monitor the TCP traffic between the two machines, this time with the firewall in router #2 enabled.
|
||||
|
||||
# telnet 10.0.0.20 80
|
||||
# tcpdump -qnnvvv -i enp0s3 host 10.0.0.20
|
||||
|
||||
What if you want to only allow incoming connections to the web server (port 80) from 192.168.0.18 and block connections from other sources in the 192.168.0.0/24 network?
|
||||
|
||||
In the web server’s firewall, add the following rules:
|
||||
|
||||
# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.18/24" service name="http" accept'
|
||||
# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.18/24" service name="http" accept' --permanent
|
||||
# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.0/24" service name="http" drop'
|
||||
# firewall-cmd --add-rich-rule 'rule family="ipv4" source address="192.168.0.0/24" service name="http" drop' --permanent
|
||||
|
||||
Now you can make HTTP requests to the web server, from 192.168.0.18 and from some other machine in 192.168.0.0/24. In the first case the connection should complete successfully, whereas in the second it will eventually timeout.
|
||||
|
||||
To do so, any of the following commands will do the trick:
|
||||
|
||||
# telnet 10.0.0.20 80
|
||||
# wget 10.0.0.20
|
||||
|
||||
I strongly advise you to check out the [Firewalld Rich Language][4] documentation in the Fedora Project Wiki for further details on rich rules.
|
||||
|
||||
### Network Address Translation in RHEL 7 ###
|
||||
|
||||
Network Address Translation (NAT) is the process where a group of computers (it can also be just one of them) in a private network are assigned an unique public IP address. As result, they are still uniquely identified by their own private IP address inside the network but to the outside they all “seem” the same.
|
||||
|
||||
In addition, NAT makes it possible that computers inside a network sends requests to outside resources (like the Internet) and have the corresponding responses be sent back to the source system only.
|
||||
|
||||
Let’s now consider the following scenario:
|
||||
|
||||
|
||||
|
||||
Network Address Translation
|
||||
|
||||
In router #2, we will move the enp0s3 interface to the external zone, and enp0s8 to the internal zone, where masquerading, or NAT, is enabled by default:
|
||||
|
||||
# firewall-cmd --list-all --zone=external
|
||||
# firewall-cmd --change-interface=enp0s3 --zone=external
|
||||
# firewall-cmd --change-interface=enp0s3 --zone=external --permanent
|
||||
# firewall-cmd --change-interface=enp0s8 --zone=internal
|
||||
# firewall-cmd --change-interface=enp0s8 --zone=internal --permanent
|
||||
|
||||
For our current setup, the internal zone – along with everything that is enabled in it will be the default zone:
|
||||
|
||||
# firewall-cmd --set-default-zone=internal
|
||||
|
||||
Next, let’s reload firewall rules and keep state information:
|
||||
|
||||
# firewall-cmd --reload
|
||||
|
||||
Finally, let’s add router #2 as default gateway in the web server:
|
||||
|
||||
# ip route add default via 10.0.0.18
|
||||
|
||||
You can now verify that you can ping router #1 and an external site (tecmint.com, for example) from the web server:
|
||||
|
||||
# ping -c 2 192.168.0.1
|
||||
# ping -c 2 tecmint.com
|
||||
|
||||
|
||||
|
||||
Verify Network Routing
|
||||
|
||||
### Setting Kernel Runtime Parameters in RHEL 7 ###
|
||||
|
||||
In Linux, you are allowed to change, enable, and disable the kernel runtime parameters, and RHEL is no exception. The /proc/sys interface (sysctl) lets you set runtime parameters on-the-fly to modify the system’s behavior without much hassle when operating conditions change.
|
||||
|
||||
To do so, the echo shell built-in is used to write to files inside /proc/sys/<category>, where <category> is most likely one of the following directories:
|
||||
|
||||
- dev: parameters for specific devices connected to the machine.
|
||||
- fs: filesystem configuration (quotas and inodes, for example).
|
||||
- kernel: kernel-specific configuration.
|
||||
- net: network configuration.
|
||||
- vm: use of the kernel’s virtual memory.
|
||||
|
||||
To display the list of all the currently available values, run
|
||||
|
||||
# sysctl -a | less
|
||||
|
||||
In Part 1, we changed the value of the net.ipv4.ip_forward parameter by doing
|
||||
|
||||
# echo 1 > /proc/sys/net/ipv4/ip_forward
|
||||
|
||||
in order to allow a Linux machine to act as router.
|
||||
|
||||
Another runtime parameter that you may want to set is kernel.sysrq, which enables the Sysrq key in your keyboard to instruct the system to perform gracefully some low-level functions, such as rebooting the system if it has frozen for some reason:
|
||||
|
||||
# echo 1 > /proc/sys/kernel/sysrq
|
||||
|
||||
To display the value of a specific parameter, use sysctl as follows:
|
||||
|
||||
# sysctl <parameter.name>
|
||||
|
||||
For example,
|
||||
|
||||
# sysctl net.ipv4.ip_forward
|
||||
# sysctl kernel.sysrq
|
||||
|
||||
Some parameters, such as the ones mentioned above, require only one value, whereas others (for example, fs.inode-state) require multiple values:
|
||||
|
||||
|
||||
|
||||
Check Kernel Parameters
|
||||
|
||||
In either case, you need to read the kernel’s documentation before making any changes.
|
||||
|
||||
Please note that these settings will go away when the system is rebooted. To make these changes permanent, we will need to add .conf files inside the /etc/sysctl.d as follows:
|
||||
|
||||
# echo "net.ipv4.ip_forward = 1" > /etc/sysctl.d/10-forward.conf
|
||||
|
||||
(where the number 10 indicates the order of processing relative to other files in the same directory).
|
||||
|
||||
and enable the changes with
|
||||
|
||||
# sysctl -p /etc/sysctl.d/10-forward.conf
|
||||
|
||||
### Summary ###
|
||||
|
||||
In this tutorial we have explained the basics of packet filtering, network address translation, and setting kernel runtime parameters on a running system and persistently across reboots. I hope you have found this information useful, and as always, we look forward to hearing from you!
|
||||
Don’t hesitate to share with us your questions, comments, or suggestions using the form below.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/perform-packet-filtering-network-address-translation-and-set-kernel-runtime-parameters-in-rhel/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/how-to-setup-and-configure-static-network-routing-in-rhel/
|
||||
[2]:http://www.tecmint.com/firewalld-rules-for-centos-7/
|
||||
[3]:http://www.tecmint.com/12-tcpdump-commands-a-network-sniffer-tool/
|
||||
[4]:https://fedoraproject.org/wiki/Features/FirewalldRichLanguage
|
||||
@ -0,0 +1,183 @@
|
||||
Translating by ictlyh
|
||||
Part 3 - How to Produce and Deliver System Activity Reports Using Linux Toolsets
|
||||
================================================================================
|
||||
As a system engineer, you will often need to produce reports that show the utilization of your system’s resources in order to make sure that: 1) they are being utilized optimally, 2) prevent bottlenecks, and 3) ensure scalability, among other reasons.
|
||||
|
||||
|
||||
|
||||
RHCE: Monitor Linux Performance Activity Reports – Part 3
|
||||
|
||||
Besides the well-known native Linux tools that are used to check disk, memory, and CPU usage – to name a few examples, Red Hat Enterprise Linux 7 provides two additional toolsets to enhance the data you can collect for your reports: sysstat and dstat.
|
||||
|
||||
In this article we will describe both, but let’s first start by reviewing the usage of the classic tools.
|
||||
|
||||
### Native Linux Tools ###
|
||||
|
||||
With df, you will be able to report disk space and inode usage of by filesystem. You need to monitor both because a lack of space will prevent you from being able to save further files (and may even cause the system to crash), just like running out of inodes will mean you can’t link further files with their corresponding data structures, thus producing the same effect: you won’t be able to save those files to disk.
|
||||
|
||||
# df -h [Display output in human-readable form]
|
||||
# df -h --total [Produce a grand total]
|
||||
|
||||
|
||||
|
||||
Check Linux Total Disk Usage
|
||||
|
||||
# df -i [Show inode count by filesystem]
|
||||
# df -i --total [Produce a grand total]
|
||||
|
||||
|
||||
|
||||
Check Linux Total inode Numbers
|
||||
|
||||
With du, you can estimate file space usage by either file, directory, or filesystem.
|
||||
|
||||
For example, let’s see how much space is used by the /home directory, which includes all of the user’s personal files. The first command will return the overall space currently used by the entire /home directory, whereas the second will also display a disaggregated list by sub-directory as well:
|
||||
|
||||
# du -sch /home
|
||||
# du -sch /home/*
|
||||
|
||||
|
||||
|
||||
Check Linux Directory Disk Size
|
||||
|
||||
Don’t Miss:
|
||||
|
||||
- [12 ‘df’ Command Examples to Check Linux Disk Space Usage][1]
|
||||
- [10 ‘du’ Command Examples to Find Disk Usage of Files/Directories][2]
|
||||
|
||||
Another utility that can’t be missing from your toolset is vmstat. It will allow you to see at a quick glance information about processes, CPU and memory usage, disk activity, and more.
|
||||
|
||||
If run without arguments, vmstat will return averages since the last reboot. While you may use this form of the command once in a while, it will be more helpful to take a certain amount of system utilization samples, one after another, with a defined time separation between samples.
|
||||
|
||||
For example,
|
||||
|
||||
# vmstat 5 10
|
||||
|
||||
will return 10 samples taken every 5 seconds:
|
||||
|
||||
|
||||
|
||||
Check Linux System Performance
|
||||
|
||||
As you can see in the above picture, the output of vmstat is divided by columns: procs (processes), memory, swap, io, system, and cpu. The meaning of each field can be found in the FIELD DESCRIPTION sections in the man page of vmstat.
|
||||
|
||||
Where can vmstat come in handy? Let’s examine the behavior of the system before and during a yum update:
|
||||
|
||||
# vmstat -a 1 5
|
||||
|
||||
|
||||
|
||||
Vmstat Linux Performance Monitoring
|
||||
|
||||
Please note that as files are being modified on disk, the amount of active memory increases and so does the number of blocks written to disk (bo) and the CPU time that is dedicated to user processes (us).
|
||||
|
||||
Or during the saving process of a large file directly to disk (caused by dsync):
|
||||
|
||||
# vmstat -a 1 5
|
||||
# dd if=/dev/zero of=dummy.out bs=1M count=1000 oflag=dsync
|
||||
|
||||
|
||||
|
||||
VmStat Linux Disk Performance Monitoring
|
||||
|
||||
In this case, we can see a yet larger number of blocks being written to disk (bo), which was to be expected, but also an increase of the amount of CPU time that it has to wait for I/O operations to complete before processing tasks (wa).
|
||||
|
||||
**Don’t Miss**: [Vmstat – Linux Performance Monitoring][3]
|
||||
|
||||
### Other Linux Tools ###
|
||||
|
||||
As mentioned in the introduction of this chapter, there are other tools that you can use to check the system status and utilization (they are not only provided by Red Hat but also by other major distributions from their officially supported repositories).
|
||||
|
||||
The sysstat package contains the following utilities:
|
||||
|
||||
- sar (collect, report, or save system activity information).
|
||||
- sadf (display data collected by sar in multiple formats).
|
||||
- mpstat (report processors related statistics).
|
||||
- iostat (report CPU statistics and I/O statistics for devices and partitions).
|
||||
- pidstat (report statistics for Linux tasks).
|
||||
- nfsiostat (report input/output statistics for NFS).
|
||||
- cifsiostat (report CIFS statistics) and
|
||||
- sa1 (collect and store binary data in the system activity daily data file.
|
||||
- sa2 (write a daily report in the /var/log/sa directory) tools.
|
||||
|
||||
whereas dstat adds some extra features to the functionality provided by those tools, along with more counters and flexibility. You can find an overall description of each tool by running yum info sysstat or yum info dstat, respectively, or checking the individual man pages after installation.
|
||||
|
||||
To install both packages:
|
||||
|
||||
# yum update && yum install sysstat dstat
|
||||
|
||||
The main configuration file for sysstat is /etc/sysconfig/sysstat. You will find the following parameters in that file:
|
||||
|
||||
# How long to keep log files (in days).
|
||||
# If value is greater than 28, then log files are kept in
|
||||
# multiple directories, one for each month.
|
||||
HISTORY=28
|
||||
# Compress (using gzip or bzip2) sa and sar files older than (in days):
|
||||
COMPRESSAFTER=31
|
||||
# Parameters for the system activity data collector (see sadc manual page)
|
||||
# which are used for the generation of log files.
|
||||
SADC_OPTIONS="-S DISK"
|
||||
# Compression program to use.
|
||||
ZIP="bzip2"
|
||||
|
||||
When sysstat is installed, two cron jobs are added and enabled in /etc/cron.d/sysstat. The first job runs the system activity accounting tool every 10 minutes and stores the reports in /var/log/sa/saXX where XX is the day of the month.
|
||||
|
||||
Thus, /var/log/sa/sa05 will contain all the system activity reports from the 5th of the month. This assumes that we are using the default value in the HISTORY variable in the configuration file above:
|
||||
|
||||
*/10 * * * * root /usr/lib64/sa/sa1 1 1
|
||||
|
||||
The second job generates a daily summary of process accounting at 11:53 pm every day and stores it in /var/log/sa/sarXX files, where XX has the same meaning as in the previous example:
|
||||
|
||||
53 23 * * * root /usr/lib64/sa/sa2 -A
|
||||
|
||||
For example, you may want to output system statistics from 9:30 am through 5:30 pm of the sixth of the month to a .csv file that can easily be viewed using LibreOffice Calc or Microsoft Excel (this approach will also allow you to create charts or graphs):
|
||||
|
||||
# sadf -s 09:30:00 -e 17:30:00 -dh /var/log/sa/sa06 -- | sed 's/;/,/g' > system_stats20150806.csv
|
||||
|
||||
You could alternatively use the -j flag instead of -d in the sadf command above to output the system stats in JSON format, which could be useful if you need to consume the data in a web application, for example.
|
||||
|
||||
|
||||
|
||||
Linux System Statistics
|
||||
|
||||
Finally, let’s see what dstat has to offer. Please note that if run without arguments, dstat assumes -cdngy by default (short for CPU, disk, network, memory pages, and system stats, respectively), and adds one line every second (execution can be interrupted anytime with Ctrl + C):
|
||||
|
||||
# dstat
|
||||
|
||||
|
||||
|
||||
Linux Disk Statistics Monitoring
|
||||
|
||||
To output the stats to a .csv file, use the –output flag followed by a file name. Let’s see how this looks on LibreOffice Calc:
|
||||
|
||||
|
||||
|
||||
Monitor Linux Statistics Output
|
||||
|
||||
I strongly advise you to check out the man page of dstat, included with this article along with the man page of sysstat in PDF format for your reading convenience. You will find several other options that will help you create custom and detailed system activity reports.
|
||||
|
||||
**Don’t Miss**: [Sysstat – Linux Usage Activity Monitoring Tool][4]
|
||||
|
||||
### Summary ###
|
||||
|
||||
In this guide we have explained how to use both native Linux tools and specific utilities provided with RHEL 7 in order to produce reports on system utilization. At one point or another, you will come to rely on these reports as best friends.
|
||||
|
||||
You will probably have used other tools that we have not covered in this tutorial. If so, feel free to share them with the rest of the community along with any other suggestions / questions / comments that you may have- using the form below.
|
||||
|
||||
We look forward to hearing from you.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-performance-monitoring-and-file-system-statistics-reports/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/how-to-check-disk-space-in-linux/
|
||||
[2]:http://www.tecmint.com/check-linux-disk-usage-of-files-and-directories/
|
||||
[3]:http://www.tecmint.com/linux-performance-monitoring-with-vmstat-and-iostat-commands/
|
||||
[4]:http://www.tecmint.com/install-sysstat-in-linux/
|
||||
@ -1,254 +0,0 @@
|
||||
RHCSA Series: Editing Text Files with Nano and Vim / Analyzing text with grep and regexps – Part 4
|
||||
================================================================================
|
||||
Every system administrator has to deal with text files as part of his daily responsibilities. That includes editing existing files (most likely configuration files), or creating new ones. It has been said that if you want to start a holy war in the Linux world, you can ask sysadmins what their favorite text editor is and why. We are not going to do that in this article, but will present a few tips that will be helpful to use two of the most widely used text editors in RHEL 7: nano (due to its simplicity and easiness of use, specially to new users), and vi/m (due to its several features that convert it into more than a simple editor). I am sure that you can find many more reasons to use one or the other, or perhaps some other editor such as emacs or pico. It’s entirely up to you.
|
||||
|
||||
|
||||
|
||||
RHCSA: Editing Text Files with Nano and Vim – Part 4
|
||||
|
||||
### Editing Files with Nano Editor ###
|
||||
|
||||
To launch nano, you can either just type nano at the command prompt, optionally followed by a filename (in this case, if the file exists, it will be opened in edition mode). If the file does not exist, or if we omit the filename, nano will also be opened in edition mode but will present a blank screen for us to start typing:
|
||||
|
||||
|
||||
|
||||
Nano Editor
|
||||
|
||||
As you can see in the previous image, nano displays at the bottom of the screen several functions that are available via the indicated shortcuts (^, aka caret, indicates the Ctrl key). To name a few of them:
|
||||
|
||||
- Ctrl + G: brings up the help menu with a complete list of functions and descriptions:Ctrl + X: exits the current file. If changes have not been saved, they are discarded.
|
||||
- Ctrl + R: lets you choose a file to insert its contents into the present file by specifying a full path.
|
||||
|
||||
|
||||
|
||||
Nano Editor Help Menu
|
||||
|
||||
- Ctrl + O: saves changes made to a file. It will let you save the file with the same name or a different one. Then press Enter to confirm.
|
||||
|
||||
|
||||
|
||||
Nano Editor Save Changes Mode
|
||||
|
||||
- Ctrl + X: exits the current file. If changes have not been saved, they are discarded.
|
||||
- Ctrl + R: lets you choose a file to insert its contents into the present file by specifying a full path.
|
||||
|
||||
|
||||
|
||||
Nano: Insert File Content to Parent File
|
||||
|
||||
will insert the contents of /etc/passwd into the current file.
|
||||
|
||||
- Ctrl + K: cuts the current line.
|
||||
- Ctrl + U: paste.
|
||||
- Ctrl + C: cancels the current operation and places you at the previous screen.
|
||||
|
||||
To easily navigate the opened file, nano provides the following features:
|
||||
|
||||
- Ctrl + F and Ctrl + B move the cursor forward or backward, whereas Ctrl + P and Ctrl + N move it up or down one line at a time, respectively, just like the arrow keys.
|
||||
- Ctrl + space and Alt + space move the cursor forward and backward one word at a time.
|
||||
|
||||
Finally,
|
||||
|
||||
- Ctrl + _ (underscore) and then entering X,Y will take you precisely to Line X, column Y, if you want to place the cursor at a specific place in the document.
|
||||
|
||||
|
||||
|
||||
Navigate to Line Numbers in Nano
|
||||
|
||||
The example above will take you to line 15, column 14 in the current document.
|
||||
|
||||
If you can recall your early Linux days, specially if you came from Windows, you will probably agree that starting off with nano is the best way to go for a new user.
|
||||
|
||||
### Editing Files with Vim Editor ###
|
||||
|
||||
Vim is an improved version of vi, a famous text editor in Linux that is available on all POSIX-compliant *nix systems, such as RHEL 7. If you have the chance and can install vim, go ahead; if not, most (if not all) the tips given in this article should also work.
|
||||
|
||||
One of vim’s distinguishing features is the different modes in which it operates:
|
||||
|
||||
|
||||
- Command mode will allow you to browse through the file and enter commands, which are brief and case-sensitive combinations of one or more letters. If you need to repeat one of them a certain number of times, you can prefix it with a number (there are only a few exceptions to this rule). For example, yy (or Y, short for yank) copies the entire current line, whereas 4yy (or 4Y) copies the entire current line along with the next three lines (4 lines in total).
|
||||
- In ex mode, you can manipulate files (including saving a current file and running outside programs or commands). To enter ex mode, we must type a colon (:) starting from command mode (or in other words, Esc + :), directly followed by the name of the ex-mode command that you want to use.
|
||||
- In insert mode, which is accessed by typing the letter i, we simply enter text. Most keystrokes result in text appearing on the screen.
|
||||
- We can always enter command mode (regardless of the mode we’re working on) by pressing the Esc key.
|
||||
|
||||
Let’s see how we can perform the same operations that we outlined for nano in the previous section, but now with vim. Don’t forget to hit the Enter key to confirm the vim command!
|
||||
|
||||
To access vim’s full manual from the command line, type :help while in command mode and then press Enter:
|
||||
|
||||
|
||||
|
||||
vim Edito Help Menu
|
||||
|
||||
The upper section presents an index list of contents, with defined sections dedicated to specific topics about vim. To navigate to a section, place the cursor over it and press Ctrl + ] (closing square bracket). Note that the bottom section displays the current file.
|
||||
|
||||
1. To save changes made to a file, run any of the following commands from command mode and it will do the trick:
|
||||
|
||||
:wq!
|
||||
:x!
|
||||
ZZ (yes, double Z without the colon at the beginning)
|
||||
|
||||
2. To exit discarding changes, use :q!. This command will also allow you to exit the help menu described above, and return to the current file in command mode.
|
||||
|
||||
3. Cut N number of lines: type Ndd while in command mode.
|
||||
|
||||
4. Copy M number of lines: type Myy while in command mode.
|
||||
|
||||
5. Paste lines that were previously cutted or copied: press the P key while in command mode.
|
||||
|
||||
6. To insert the contents of another file into the current one:
|
||||
|
||||
:r filename
|
||||
|
||||
For example, to insert the contents of `/etc/fstab`, do:
|
||||
|
||||
|
||||
|
||||
Insert Content of File in vi Editor
|
||||
|
||||
7. To insert the output of a command into the current document:
|
||||
|
||||
:r! command
|
||||
|
||||
For example, to insert the date and time in the line below the current position of the cursor:
|
||||
|
||||
|
||||
|
||||
Insert Time an Date in vi Editor
|
||||
|
||||
In another article that I wrote for, ([Part 2 of the LFCS series][1]), I explained in greater detail the keyboard shortcuts and functions available in vim. You may want to refer to that tutorial for further examples on how to use this powerful text editor.
|
||||
|
||||
### Analyzing Text with Grep and Regular Expressions ###
|
||||
|
||||
By now you have learned how to create and edit files using nano or vim. Say you become a text editor ninja, so to speak – now what? Among other things, you will also need how to search for regular expressions inside text.
|
||||
|
||||
A regular expression (also known as “regex” or “regexp“) is a way of identifying a text string or pattern so that a program can compare the pattern against arbitrary text strings. Although the use of regular expressions along with grep would deserve an entire article on its own, let us review the basics here:
|
||||
|
||||
**1. The simplest regular expression is an alphanumeric string (i.e., the word “svm”) or two (when two are present, you can use the | (OR) operator):**
|
||||
|
||||
# grep -Ei 'svm|vmx' /proc/cpuinfo
|
||||
|
||||
The presence of either of those two strings indicate that your processor supports virtualization:
|
||||
|
||||
|
||||
|
||||
Regular Expression Example
|
||||
|
||||
**2. A second kind of a regular expression is a range list, enclosed between square brackets.**
|
||||
|
||||
For example, `c[aeiou]t` matches the strings cat, cet, cit, cot, and cut, whereas `[a-z]` and `[0-9]` match any lowercase letter or decimal digit, respectively. If you want to repeat the regular expression X certain number of times, type `{X}` immediately following the regexp.
|
||||
|
||||
For example, let’s extract the UUIDs of storage devices from `/etc/fstab`:
|
||||
|
||||
# grep -Ei '[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}' -o /etc/fstab
|
||||
|
||||
|
||||
|
||||
Extract String from a File
|
||||
|
||||
The first expression in brackets `[0-9a-f]` is used to denote lowercase hexadecimal characters, and `{8}` is a quantifier that indicates the number of times that the preceding match should be repeated (the first sequence of characters in an UUID is a 8-character long hexadecimal string).
|
||||
|
||||
The parentheses, the `{4}` quantifier, and the hyphen indicate that the next sequence is a 4-character long hexadecimal string, and the quantifier that follows `({3})` denote that the expression should be repeated 3 times.
|
||||
|
||||
Finally, the last sequence of 12-character long hexadecimal string in the UUID is retrieved with `[0-9a-f]{12}`, and the -o option prints only the matched (non-empty) parts of the matching line in /etc/fstab.
|
||||
|
||||
**3. POSIX character classes.**
|
||||
|
||||
注：表格
|
||||
<table cellspacing="0" border="0">
|
||||
<colgroup width="201"></colgroup>
|
||||
<colgroup width="440"></colgroup>
|
||||
<tbody>
|
||||
<tr>
|
||||
<td align="center" height="25" bgcolor="#999999" style="border: 1px solid #000000;"><b>Character Class</b></td>
|
||||
<td align="center" bgcolor="#999999" style="border: 1px solid #000000;"><b>Matches…</b></td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:alnum:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any alphanumeric [a-zA-Z0-9] character</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:alpha:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any alphabetic [a-zA-Z] character</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:blank:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Spaces or tabs</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:cntrl:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any control characters (ASCII 0 to 32)</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:digit:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any numeric digits [0-9]</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:graph:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any visible characters</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:lower:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any lowercase [a-z] character</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:print:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any non-control characters</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:space:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any whitespace</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:punct:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any punctuation marks</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:upper:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any uppercase [A-Z] character</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:xdigit:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any hex digits [0-9a-fA-F]</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [:word:]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> Any letters, numbers, and underscores [a-zA-Z0-9_]</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
|
||||
For example, we may be interested in finding out what the used UIDs and GIDs (refer to [Part 2][2] of this series to refresh your memory) are for real users that have been added to our system. Thus, we will search for sequences of 4 digits in /etc/passwd:
|
||||
|
||||
# grep -Ei [[:digit:]]{4} /etc/passwd
|
||||
|
||||
|
||||
|
||||
Search For a String in File
|
||||
|
||||
The above example may not be the best case of use of regular expressions in the real world, but it clearly illustrates how to use POSIX character classes to analyze text along with grep.
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
In this article we have provided some tips to make the most of nano and vim, two text editors for the command-line users. Both tools are supported by extensive documentation, which you can consult in their respective official web sites (links given below) and using the suggestions given in [Part 1][3] of this series.
|
||||
|
||||
#### Reference Links ####
|
||||
|
||||
- [http://www.nano-editor.org/][4]
|
||||
- [http://www.vim.org/][5]
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/rhcsa-exam-how-to-use-nano-vi-editors/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[译者ID](https://github.com/译者ID)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/vi-editor-usage/
|
||||
[2]:http://www.tecmint.com/file-and-directory-management-in-linux/
|
||||
[3]:http://www.tecmint.com/rhcsa-exam-reviewing-essential-commands-system-documentation/
|
||||
[4]:http://www.nano-editor.org/
|
||||
[5]:http://www.vim.org/
|
||||
@ -1,3 +1,5 @@
|
||||
FSSlc translating
|
||||
|
||||
RHCSA Series: Process Management in RHEL 7: Boot, Shutdown, and Everything in Between – Part 5
|
||||
================================================================================
|
||||
We will start this article with an overall and brief revision of what happens since the moment you press the Power button to turn on your RHEL 7 server until you are presented with the login screen in a command line interface.
|
||||
@ -213,4 +215,4 @@ via: http://www.tecmint.com/rhcsa-exam-boot-process-and-process-management/
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/dmesg-commands/
|
||||
[2]:http://www.tecmint.com/systemd-replaces-init-in-linux/
|
||||
[3]:http://www.tecmint.com/how-to-kill-a-process-in-linux/
|
||||
[3]:http://www.tecmint.com/how-to-kill-a-process-in-linux/
|
||||
|
||||
@ -0,0 +1,183 @@
|
||||
如何配置MongoDB副本集（Replica Set）
|
||||
================================================================================
|
||||
MongoDB已经成为市面上最知名的NoSQL数据库。MongoDB是面向文档的，它的无模式设计使得它在各种各样的WEB应用当中广受欢迎。最让我喜欢的特性之一是它的副本集，副本集将同一数据的多份拷贝放在一组mongod节点上，从而实现数据的冗余以及高可用性。
|
||||
|
||||
这篇教程将向你介绍如何配置一个MongoDB副本集。
|
||||
|
||||
副本集的最常见配置涉及到一个主节点以及多个副节点。这之后启动的复制行为会从这个主节点到其他副节点。副本集不止可以针对意外的硬件故障和停机事件对数据库提供保护，同时也因为提供了更多的结点从而提高了数据库客户端数据读取的吞吐量。
|
||||
|
||||
### 配置环境 ###
|
||||
|
||||
这个教程里，我们会配置一个包括一个主节点以及两个副节点的副本集。
|
||||
|
||||
|
||||
|
||||
为了达到这个目的，我们使用了3个运行在VirtualBox上的虚拟机。我会在这些虚拟机上安装Ubuntu 14.04，并且安装MongoDB官方包。
|
||||
|
||||
我会在一个虚拟机实例上配置好需要的环境，然后将它克隆到其他的虚拟机实例上。因此，选择一个名为master的虚拟机，执行以下安装过程。
|
||||
|
||||
首先，我们需要在apt中增加一个MongoDB密钥：
|
||||
|
||||
$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
|
||||
|
||||
然后，将官方的MongoDB仓库添加到source.list中：
|
||||
|
||||
$ sudo su
|
||||
# echo "deb http://repo.mongodb.org/apt/ubuntu "$(lsb_release -sc)"/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
|
||||
|
||||
接下来更新apt仓库并且安装MongoDB。
|
||||
|
||||
$ sudo apt-get update
|
||||
$ sudo apt-get install -y mongodb-org
|
||||
|
||||
现在对/etc/mongodb.conf做一些更改
|
||||
|
||||
auth = true
|
||||
dbpath=/var/lib/mongodb
|
||||
logpath=/var/log/mongodb/mongod.log
|
||||
logappend=true
|
||||
keyFile=/var/lib/mongodb/keyFile
|
||||
replSet=myReplica
|
||||
|
||||
第一行的作用是确认我们的数据库需要验证才可以使用的。keyfile用来配置用于MongoDB结点间复制行为的密钥文件。replSet用来为副本集设置一个名称。
|
||||
|
||||
接下来我们创建一个用于所有实例的密钥文件。
|
||||
|
||||
$ echo -n "MyRandomStringForReplicaSet" | md5sum > keyFile
|
||||
|
||||
这将会创建一个含有MD5字符串的密钥文件，但是由于其中包含了一些噪音，我们需要对他们清理后才能正式在MongoDB中使用。
|
||||
|
||||
$ echo -n "MyReplicaSetKey" | md5sum|grep -o "[0-9a-z]\+" > keyFile
|
||||
|
||||
grep命令的作用的是把将空格等我们不想要的内容过滤掉之后的MD5字符串打印出来。
|
||||
|
||||
现在我们对密钥文件进行一些操作，让它真正可用。
|
||||
|
||||
$ sudo cp keyFile /var/lib/mongodb
|
||||
$ sudo chown mongodb:nogroup keyFile
|
||||
$ sudo chmod 400 keyFile
|
||||
|
||||
接下来，关闭此虚拟机。将其Ubuntu系统克隆到其他虚拟机上。
|
||||
|
||||
|
||||
|
||||
这是克隆后的副节点1和副节点2。确认你已经将它们的MAC地址重新初始化，并且克隆整个硬盘。
|
||||
|
||||
|
||||
|
||||
请注意，三个虚拟机示例需要在同一个网络中以便相互通讯。因此，我们需要它们弄到“互联网"上去。
|
||||
|
||||
这里推荐给每个虚拟机设置一个静态IP地址，而不是使用DHCP。这样它们就不至于在DHCP分配IP地址给他们的时候失去连接。
|
||||
|
||||
像下面这样编辑每个虚拟机的/etc/networks/interfaces文件。
|
||||
|
||||
在主结点上:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.2
|
||||
netmask 255.255.255.0
|
||||
|
||||
在副结点1上:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.3
|
||||
netmask 255.255.255.0
|
||||
|
||||
在副结点2上:
|
||||
|
||||
auto eth1
|
||||
iface eth1 inet static
|
||||
address 192.168.50.4
|
||||
netmask 255.255.255.0
|
||||
|
||||
由于我们没有DNS服务，所以需要设置设置一下/etc/hosts这个文件，手工将主机名称放到次文件中。
|
||||
|
||||
在主结点上:
|
||||
|
||||
127.0.0.1 localhost primary
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
在副结点1上:
|
||||
|
||||
127.0.0.1 localhost secondary1
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
在副结点2上:
|
||||
|
||||
127.0.0.1 localhost secondary2
|
||||
192.168.50.2 primary
|
||||
192.168.50.3 secondary1
|
||||
192.168.50.4 secondary2
|
||||
|
||||
使用ping命令检查各个结点之间的连接。
|
||||
|
||||
$ ping primary
|
||||
$ ping secondary1
|
||||
$ ping secondary2
|
||||
|
||||
### 配置副本集 ###
|
||||
|
||||
验证各个结点可以正常连通后，我们就可以新建一个管理员用户，用于之后的副本集操作。
|
||||
|
||||
在主节点上，打开/etc/mongodb.conf文件，将auth和replSet两项注释掉。
|
||||
|
||||
dbpath=/var/lib/mongodb
|
||||
logpath=/var/log/mongodb/mongod.log
|
||||
logappend=true
|
||||
#auth = true
|
||||
keyFile=/var/lib/mongodb/keyFile
|
||||
#replSet=myReplica
|
||||
|
||||
重启mongod进程。
|
||||
|
||||
$ sudo service mongod restart
|
||||
|
||||
连接MongoDB后，新建管理员用户。
|
||||
|
||||
> use admin
|
||||
> db.createUser({
|
||||
user:"admin",
|
||||
pwd:"
|
||||
})
|
||||
$ sudo service mongod restart
|
||||
|
||||
连接到MongoDB，用以下命令将secondary1和secondary2节点添加到我们的副本集中。
|
||||
|
||||
> use admin
|
||||
> db.auth("admin","myreallyhardpassword")
|
||||
> rs.initiate()
|
||||
> rs.add ("secondary1:27017")
|
||||
> rs.add("secondary2:27017")
|
||||
|
||||
|
||||
现在副本集到手了，可以开始我们的项目了。参照 [official driver documentation][1] 来了解如何连接到副本集。如果你想要用Shell来请求数据，那么你需要连接到主节点上来插入或者请求数据，副节点不行。如果你执意要尝试用附件点操作，那么以下错误信息就蹦出来招呼你了。
|
||||
|
||||
myReplica:SECONDARY>
|
||||
myReplica:SECONDARY> show databases
|
||||
2015-05-10T03:09:24.131+0000 E QUERY Error: listDatabases failed:{ "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }
|
||||
at Error ()
|
||||
at Mongo.getDBs (src/mongo/shell/mongo.js:47:15)
|
||||
at shellHelper.show (src/mongo/shell/utils.js:630:33)
|
||||
at shellHelper (src/mongo/shell/utils.js:524:36)
|
||||
at (shellhelp2):1:1 at src/mongo/shell/mongo.js:47
|
||||
|
||||
希望这篇教程能对你有所帮助。你可以使用Vagrant来自动完成你的本地环境配置，并且加速你的代码。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://xmodulo.com/setup-replica-set-mongodb.html
|
||||
|
||||
作者：[Christopher Valerio][a]
|
||||
译者：[mr-ping](https://github.com/mr-ping)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://xmodulo.com/author/valerio
|
||||
[1]:http://docs.mongodb.org/ecosystem/drivers/
|
||||
@ -0,0 +1,348 @@
|
||||
Shilpa Nair 分享了她面试 RedHat Linux 包管理方面的经验
|
||||
========================================================================
|
||||
**Shilpa Nair 刚于2015年毕业。她之后去了一家位于 Noida，Delhi 的国家新闻电视台，应聘实习生的岗位。在她去年毕业季的时候，常逛 Tecmint 寻求作业上的帮助。从那时开始，她就常去 Tecmint。**
|
||||
|
||||
|
||||
|
||||
有关 RPM 方面的 Linux 面试题
|
||||
|
||||
所有的问题和回答都是 Shilpa Nair 根据回忆重写的。
|
||||
|
||||
> “大家好！我是来自 Delhi 的Shilpa Nair。我不久前才顺利毕业，正寻找一个实习的机会。在大学早期的时候，我就对 UNIX 十分喜爱，所以我也希望这个机会能适合我，满足我的兴趣。我被提问了很多问题，大部分都是关于 RedHat 包管理的基础问题。”
|
||||
|
||||
下面就是我被问到的问题，和对应的回答。我仅贴出了与 RedHat GNU/Linux 包管理相关的，也是主要被提问的。
|
||||
|
||||
### 1，里如何查找一个包安装与否？假设你需要确认 ‘nano’ 有没有安装，你怎么做？ ###
|
||||
|
||||
> **回答**：为了确认 nano 软件包有没有安装，我们可以使用 rpm 命令，配合 -q 和 -a 选项来查询所有已安装的包
|
||||
>
|
||||
> # rpm -qa nano
|
||||
> OR
|
||||
> # rpm -qa | grep -i nano
|
||||
>
|
||||
> nano-2.3.1-10.el7.x86_64
|
||||
>
|
||||
> 同时包的名字必须是完成的，不完整的包名返回提示，不打印任何东西，就是说这包（包名字不全）未安装。下面的例子会更好理解些：
|
||||
>
|
||||
> 我们通常使用 vim 替代 vi 命令。当时如果我们查找安装包 vi/vim 的时候，我们就会看到标准输出上没有任何结果。
|
||||
>
|
||||
> # vi
|
||||
> # vim
|
||||
>
|
||||
> 尽管如此，我们仍然可以通过使用 vi/vim 命令来清楚地知道包有没有安装。Here is ... name（这句不知道）。如果我们不确切知道完整的文件名，我们可以使用通配符：
|
||||
>
|
||||
> # rpm -qa vim*
|
||||
>
|
||||
> vim-minimal-7.4.160-1.el7.x86_64
|
||||
>
|
||||
> 通过这种方式，我们可以获得任何软件包的信息，安装与否。
|
||||
|
||||
### 2. 你如何使用 rpm 命令安装 XYZ 软件包？ ###
|
||||
|
||||
> **回答**：我们可以使用 rpm 命令安装任何的软件包（*.rpm），像下面这样，选项 -i（install），-v（冗余或者显示额外的信息）和 -h（打印#号显示进度，在安装过程中）。
|
||||
>
|
||||
> # rpm -ivh peazip-1.11-1.el6.rf.x86_64.rpm
|
||||
>
|
||||
> Preparing... ################################# [100%]
|
||||
> Updating / installing...
|
||||
> 1:peazip-1.11-1.el6.rf ################################# [100%]
|
||||
>
|
||||
> 如果要升级一个早期版本的包，应加上 -U 选项，选项 -v 和 -h 可以确保我们得到用 # 号表示的冗余输出，这增加了可读性。
|
||||
|
||||
### 3. 你已经安装了一个软件包（假设是 httpd），现在你想看看软件包创建并安装的所有文件和目录，你会怎么做？ ###
|
||||
|
||||
> **回答**：使用选项 -l（列出所有文件）和 -q（查询）列出 httpd 软件包安装的所有文件（Linux哲学：所有的都是文件，包括目录）。
|
||||
>
|
||||
> # rpm -ql httpd
|
||||
>
|
||||
> /etc/httpd
|
||||
> /etc/httpd/conf
|
||||
> /etc/httpd/conf.d
|
||||
> ...
|
||||
|
||||
### 4. 假如你要移除一个软件包，叫 postfix。你会怎么做？ ###
|
||||
|
||||
> **回答**：首先我们需要知道什么包安装了 postfix。查找安装 postfix 的包名后，使用 -e（擦除/卸载软件包）和 -v（冗余输出）两个选项来实现。
|
||||
>
|
||||
> # rpm -qa postfix*
|
||||
>
|
||||
> postfix-2.10.1-6.el7.x86_64
|
||||
>
|
||||
> 然后移除 postfix，如下:
|
||||
>
|
||||
> # rpm -ev postfix-2.10.1-6.el7.x86_64
|
||||
>
|
||||
> Preparing packages...
|
||||
> postfix-2:3.0.1-2.fc22.x86_64
|
||||
|
||||
### 5. 获得一个已安装包的具体信息，如版本，发行号，安装日期，大小，总结和一个间短的描述。 ###
|
||||
|
||||
> **回答**：我们通过使用 rpm 的选项 -qi，后面接包名，可以获得关于一个已安装包的具体信息。
|
||||
>
|
||||
> 举个例子，为了获得 openssh 包的具体信息，我需要做的就是：
|
||||
>
|
||||
> # rpm -qi openssh
|
||||
>
|
||||
> [root@tecmint tecmint]# rpm -qi openssh
|
||||
> Name : openssh
|
||||
> Version : 6.8p1
|
||||
> Release : 5.fc22
|
||||
> Architecture: x86_64
|
||||
> Install Date: Thursday 28 May 2015 12:34:50 PM IST
|
||||
> Group : Applications/Internet
|
||||
> Size : 1542057
|
||||
> License : BSD
|
||||
> ....
|
||||
|
||||
### 6. 假如你不确定一个指定包的配置文件在哪，比如 httpd。你如何找到所有 httpd 提供的配置文件列表和位置。 ###
|
||||
|
||||
> **回答**： 我们需要用选项 -c 接包名，这会列出所有配置文件的名字和他们的位置。
|
||||
>
|
||||
> # rpm -qc httpd
|
||||
>
|
||||
> /etc/httpd/conf.d/autoindex.conf
|
||||
> /etc/httpd/conf.d/userdir.conf
|
||||
> /etc/httpd/conf.d/welcome.conf
|
||||
> /etc/httpd/conf.modules.d/00-base.conf
|
||||
> /etc/httpd/conf/httpd.conf
|
||||
> /etc/sysconfig/httpd
|
||||
>
|
||||
> 相似地，我们可以列出所有相关的文档文件，如下：
|
||||
>
|
||||
> # rpm -qd httpd
|
||||
>
|
||||
> /usr/share/doc/httpd/ABOUT_APACHE
|
||||
> /usr/share/doc/httpd/CHANGES
|
||||
> /usr/share/doc/httpd/LICENSE
|
||||
> ...
|
||||
>
|
||||
> 我们也可以列出所有相关的证书文件，如下：
|
||||
>
|
||||
> # rpm -qL openssh
|
||||
>
|
||||
> /usr/share/licenses/openssh/LICENCE
|
||||
>
|
||||
> 忘了说明上面的选项 -d 和 -L 分别表示 “文档” 和 “证书”，抱歉。
|
||||
|
||||
### 7. 你进入了一个配置文件，位于‘/usr/share/alsa/cards/AACI.conf’，现在你不确定该文件属于哪个包。你如何查找出包的名字？ ###
|
||||
|
||||
> **回答**：当一个包被安装后，相关的信息就存储在了数据库里。所以使用选项 -qf（-f 查询包拥有的文件）很容易追踪谁提供了上述的包。
|
||||
>
|
||||
> # rpm -qf /usr/share/alsa/cards/AACI.conf
|
||||
> alsa-lib-1.0.28-2.el7.x86_64
|
||||
>
|
||||
> 类似地，我们可以查找（谁提供的）关于任何子包，文档和证书文件的信息。
|
||||
|
||||
### 8. 你如何使用 rpm 查找最近安装的软件列表？ ###
|
||||
|
||||
> **回答**：如刚刚说的，每一样被安装的文件都记录在了数据库里。所以这并不难，通过查询 rpm 的数据库，找到最近安装软件的列表。
|
||||
>
|
||||
> 我们通过运行下面的命令，使用选项 -last（打印出最近安装的软件）达到目的。
|
||||
>
|
||||
> # rpm -qa --last
|
||||
>
|
||||
> 上面的命令会打印出所有安装的软件，最近一次安装的软件在列表的顶部。
|
||||
>
|
||||
> 如果我们关心的是找出特定的包，我们可以使用 grep 命令从列表中匹配包（假设是 sqlite ），简单如下：
|
||||
>
|
||||
> # rpm -qa --last | grep -i sqlite
|
||||
>
|
||||
> sqlite-3.8.10.2-1.fc22.x86_64 Thursday 18 June 2015 05:05:43 PM IST
|
||||
>
|
||||
> 我们也可以获得10个最近安装的软件列表，简单如下：
|
||||
>
|
||||
> # rpm -qa --last | head
|
||||
>
|
||||
> 我们可以重定义一下，输出想要的结果，简单如下：
|
||||
>
|
||||
> # rpm -qa --last | head -n 2
|
||||
>
|
||||
> 上面的命令中，-n 代表数目，后面接一个常数值。该命令是打印2个最近安装的软件的列表。
|
||||
|
||||
### 9. 安装一个包之前，你如果要检查其依赖。你会怎么做？ ###
|
||||
|
||||
> **回答**：检查一个 rpm 包（XYZ.rpm）的依赖，我们可以使用选项 -q（查询包），-p（指定包名）和 -R（查询/列出该包依赖的包，嗯，就是依赖）。
|
||||
>
|
||||
> # rpm -qpR gedit-3.16.1-1.fc22.i686.rpm
|
||||
>
|
||||
> /bin/sh
|
||||
> /usr/bin/env
|
||||
> glib2(x86-32) >= 2.40.0
|
||||
> gsettings-desktop-schemas
|
||||
> gtk3(x86-32) >= 3.16
|
||||
> gtksourceview3(x86-32) >= 3.16
|
||||
> gvfs
|
||||
> libX11.so.6
|
||||
> ...
|
||||
|
||||
### 10. rpm 是不是一个前端的包管理工具呢？ ###
|
||||
|
||||
> **回答**：不是！rpm 是一个后端管理工具，适用于基于 Linux 发行版的 RPM （此处指 Redhat Package Management）。
|
||||
>
|
||||
> [YUM][1]，全称 Yellowdog Updater Modified，是一个 RPM 的前端工具。YUM 命令自动完成所有工作，包括解决依赖和其他一切事务。
|
||||
>
|
||||
> 最近，[DNF][2]（YUM命令升级版）在Fedora 22发行版中取代了 YUM。尽管 YUM 仍然可以在 RHEL 和 CentOS 平台使用，我们也可以安装 dnf，与 YUM 命令共存使用。据说 DNF 较于 YUM 有很多提高。
|
||||
>
|
||||
> 知道更多总是好的，保持自我更新。现在我们移步到前端部分来谈谈。
|
||||
|
||||
### 11. 你如何列出一个系统上面所有可用的仓库列表。 ###
|
||||
|
||||
> **回答**：简单地使用下面的命令，我们就可以列出一个系统上所有可用的仓库列表。
|
||||
>
|
||||
> # yum repolist
|
||||
> 或
|
||||
> # dnf repolist
|
||||
>
|
||||
> Last metadata expiration check performed 0:30:03 ago on Mon Jun 22 16:50:00 2015.
|
||||
> repo id repo name status
|
||||
> *fedora Fedora 22 - x86_64 44,762
|
||||
> ozonos Repository for Ozon OS 61
|
||||
> *updates Fedora 22 - x86_64 - Updates
|
||||
>
|
||||
> 上面的命令仅会列出可用的仓库。如果你需要列出所有的仓库，不管可用与否，可以这样做。
|
||||
>
|
||||
> # yum repolist all
|
||||
> or
|
||||
> # dnf repolist all
|
||||
>
|
||||
> Last metadata expiration check performed 0:29:45 ago on Mon Jun 22 16:50:00 2015.
|
||||
> repo id repo name status
|
||||
> *fedora Fedora 22 - x86_64 enabled: 44,762
|
||||
> fedora-debuginfo Fedora 22 - x86_64 - Debug disabled
|
||||
> fedora-source Fedora 22 - Source disabled
|
||||
> ozonos Repository for Ozon OS enabled: 61
|
||||
> *updates Fedora 22 - x86_64 - Updates enabled: 5,018
|
||||
> updates-debuginfo Fedora 22 - x86_64 - Updates - Debug
|
||||
|
||||
### 12. 你如何列出一个系统上所有可用并且安装了的包？ ###
|
||||
|
||||
> **回答**：列出一个系统上所有可用的包，我们可以这样做：
|
||||
>
|
||||
> # yum list available
|
||||
> 或
|
||||
> # dnf list available
|
||||
>
|
||||
> ast metadata expiration check performed 0:34:09 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Available Packages
|
||||
> 0ad.x86_64 0.0.18-1.fc22 fedora
|
||||
> 0ad-data.noarch 0.0.18-1.fc22 fedora
|
||||
> 0install.x86_64 2.6.1-2.fc21 fedora
|
||||
> 0xFFFF.x86_64 0.3.9-11.fc22 fedora
|
||||
> 2048-cli.x86_64 0.9-4.git20141214.723738c.fc22 fedora
|
||||
> 2048-cli-nocurses.x86_64 0.9-4.git20141214.723738c.fc22 fedora
|
||||
> ....
|
||||
>
|
||||
> 而列出一个系统上所有已安装的包，我们可以这样做。
|
||||
>
|
||||
> # yum list installed
|
||||
> or
|
||||
> # dnf list installed
|
||||
>
|
||||
> Last metadata expiration check performed 0:34:30 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Installed Packages
|
||||
> GeoIP.x86_64 1.6.5-1.fc22 @System
|
||||
> GeoIP-GeoLite-data.noarch 2015.05-1.fc22 @System
|
||||
> NetworkManager.x86_64 1:1.0.2-1.fc22 @System
|
||||
> NetworkManager-libnm.x86_64 1:1.0.2-1.fc22 @System
|
||||
> aajohan-comfortaa-fonts.noarch 2.004-4.fc22 @System
|
||||
> ....
|
||||
>
|
||||
> 而要同时满足两个要求的时候，我们可以这样做。
|
||||
>
|
||||
> # yum list
|
||||
> 或
|
||||
> # dnf list
|
||||
>
|
||||
> Last metadata expiration check performed 0:32:56 ago on Mon Jun 22 16:50:00 2015.
|
||||
> Installed Packages
|
||||
> GeoIP.x86_64 1.6.5-1.fc22 @System
|
||||
> GeoIP-GeoLite-data.noarch 2015.05-1.fc22 @System
|
||||
> NetworkManager.x86_64 1:1.0.2-1.fc22 @System
|
||||
> NetworkManager-libnm.x86_64 1:1.0.2-1.fc22 @System
|
||||
> aajohan-comfortaa-fonts.noarch 2.004-4.fc22 @System
|
||||
> acl.x86_64 2.2.52-7.fc22 @System
|
||||
> ....
|
||||
|
||||
### 13. 你会怎么分别安装和升级一个包与一组包，在一个系统上面使用 YUM/DNF？ ###
|
||||
|
||||
> **回答**：安装一个包（假设是 nano），我们可以这样做，
|
||||
>
|
||||
> # yum install nano
|
||||
>
|
||||
> 而安装一组包（假设是 Haskell），我们可以这样做，
|
||||
>
|
||||
> # yum groupinstall 'haskell'
|
||||
>
|
||||
> 升级一个包（还是 nano），我们可以这样做，
|
||||
>
|
||||
> # yum update nano
|
||||
>
|
||||
> 而为了升级一组包（还是 haskell），我们可以这样做，
|
||||
>
|
||||
> # yum groupupdate 'haskell'
|
||||
|
||||
### 14. 你会如何同步一个系统上面的所有安装软件到稳定发行版？ ###
|
||||
|
||||
> **回答**：我们可以一个系统上（假设是 CentOS 或者 Fedora）的所有包到稳定发行版，如下，
|
||||
>
|
||||
> # yum distro-sync [On CentOS/ RHEL]
|
||||
> 或
|
||||
> # dnf distro-sync [On Fedora 20之后版本]
|
||||
|
||||
似乎来面试之前你做了相当不多的功课，很好！在进一步交谈前，我还想问一两个问题。
|
||||
|
||||
### 15. 你对 YUM 本地仓库熟悉吗？你尝试过建立一个本地 YUM 仓库吗？让我们简单看看你会怎么建立一个本地 YUM 仓库。 ###
|
||||
|
||||
> **回答**：首先，感谢你的夸奖。回到问题，我必须承认我对本地 YUM 仓库十分熟悉，并且在我的本地主机上也部署过，作为测试用。
|
||||
>
|
||||
> 1. 为了建立本地 YUM 仓库，我们需要安装下面三个包：
|
||||
>
|
||||
> # yum install deltarpm python-deltarpm createrepo
|
||||
>
|
||||
> 2. 新建一个目录(假设 /home/$USER/rpm)，然后复制 RedHat/CentOS DVD 上的 RPM 包到这个文件夹下
|
||||
>
|
||||
> # mkdir /home/$USER/rpm
|
||||
> # cp /path/to/rpm/on/DVD/*.rpm /home/$USER/rpm
|
||||
>
|
||||
> 3. 新建基本的库头文件如下。
|
||||
>
|
||||
> # createrepo -v /home/$USER/rpm
|
||||
>
|
||||
> 4. 在路径 /etc/yum.repo.d 下创建一个 .repo 文件（如 abc.repo):
|
||||
>
|
||||
> cd /etc/yum.repos.d && cat << EOF > abc.repo
|
||||
> [local-installation]name=yum-local
|
||||
> baseurl=file:///home/$USER/rpm
|
||||
> enabled=1
|
||||
> gpgcheck=0
|
||||
> EOF
|
||||
|
||||
**重要**：用你的用户名替换掉 $USER。
|
||||
|
||||
以上就是创建一个本地 YUM 仓库所要做的全部工作。我们现在可以从这里安装软件了，相对快一些，安全一些，并且最重要的是不需要 Internet 连接。
|
||||
|
||||
好了！面试过程很愉快。我已经问完了。我会将你推荐给 HR。你是一个年轻且十分聪明的候选者，我们很愿意你加入进来。如果你有任何问题，你可以问我。
|
||||
|
||||
**我**：谢谢，这确实是一次愉快的面试，我感到非常幸运今天，然后这次面试就毁了。。。
|
||||
|
||||
显然，不会在这里结束。我问了很多问题，比如他们正在做的项目。我会担任什么角色，负责什么，，，balabalabala
|
||||
|
||||
小伙伴们，3天以前 HR 轮的所有问题到时候也会被写成文档。希望我当时表现不错。感谢你们所有的祝福。
|
||||
|
||||
谢谢伙伴们和 Tecmint，花时间来编辑我的面试经历。我相信 Tecmint 好伙伴们做了很大的努力，必要要赞一个。当我们与他人分享我们的经历的时候，其他人从我们这里知道了更多，而我们自己则发现了自己的不足。
|
||||
|
||||
这增加了我们的信心。如果你最近也有任何类似的面试经历，别自己蔵着。分享出来！让我们所有人都知道。你可以使用如下的格式来与我们分享你的经历。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/linux-rpm-package-management-interview-questions/
|
||||
|
||||
作者：[Avishek Kumar][a]
|
||||
译者：[wi-cuckoo](https://github.com/wi-cuckoo)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/20-linux-yum-yellowdog-updater-modified-commands-for-package-mangement/
|
||||
[2]:http://www.tecmint.com/dnf-commands-for-fedora-rpm-package-management/
|
||||
@ -0,0 +1,62 @@
|
||||
Darkstat一个基于网络的流量分析器 - 在Linux中安装
|
||||
================================================================================
|
||||
Darkstat是一个简易的，基于网络的流量分析程序。它可以在主流的操作系统如Linux、Solaris、MAC、AIX上工作。它以守护进程的形式持续工作在后台并不断地嗅探网络数据并以简单易懂的形式展现在网页上。它可以为主机生成流量报告，鉴别特定主机上哪些端口打开并且兼容IPv6。让我们看下如何在Linux中安装和配置它。
|
||||
|
||||
### 在Linux中安装配置Darkstat ###
|
||||
|
||||
** 在Fedora/CentOS/RHEL中安装Darkstat：**
|
||||
|
||||
要在Fedora/RHEL和CentOS中安装，运行下面的命令。
|
||||
|
||||
sudo yum install darkstat
|
||||
|
||||
**在Ubuntu/Debian中安装Darkstat：**
|
||||
|
||||
运行下面的命令在Ubuntu和Debian中安装。
|
||||
|
||||
sudo apt-get install darkstat
|
||||
|
||||
恭喜你，Darkstat已经在你的Linux中安装了。
|
||||
|
||||
### 配置 Darkstat ###
|
||||
|
||||
为了正确运行这个程序，我恩需要执行一些基本的配置。运行下面的命令用gedit编辑器打开/etc/darkstat/init.cfg文件。
|
||||
|
||||
sudo gedit /etc/darkstat/init.cfg
|
||||
|
||||
|
||||
编辑 Darkstat
|
||||
|
||||
修改START_DARKSTAT这个参数为yes，并在“INTERFACE”中提供你的网络接口。确保取消了DIR、PORT、BINDIP和LOCAL这些参数的注释。如果你希望绑定Darkstat到特定的IP，在BINDIP中提供它
|
||||
|
||||
### 启动Darkstat守护进程 ###
|
||||
|
||||
安装并配置完Darkstat后，运行下面的命令启动它的守护进程。
|
||||
|
||||
sudo /etc/init.d/darkstat start
|
||||
|
||||
|
||||
|
||||
你可以用下面的命令来在开机时启动Darkstat：
|
||||
|
||||
chkconfig darkstat on
|
||||
|
||||
打开浏览器并打开**http://localhost:666**，它会显示Darkstat的网页界面。使用这个工具来分析你的网络流量。
|
||||
|
||||
|
||||
|
||||
### 总结 ###
|
||||
|
||||
它是一个占用很少内存的轻量级工具。这个工具流行的原因是简易、易于配置和使用。这是一个对系统管理员而言必须拥有的程序
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://linuxpitstop.com/install-darkstat-on-ubuntu-linux/
|
||||
|
||||
作者：[Aun][a]
|
||||
译者：[geekpi](https://github.com/geekpi)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linuxpitstop.com/author/aun/
|
||||
@ -0,0 +1,99 @@
|
||||
如何在 Linux 中从 Google Play 商店里下载 apk 文件
|
||||
================================================================================
|
||||
假设你想在你的 Android 设备中安装一个 Android 应用，然而由于某些原因，你不能在 Andor 设备上访问 Google Play 商店。接着你该怎么做呢？在不访问 Google Play 商店的前提下安装应用的一种可能的方法是使用其他的手段下载该应用的 APK 文件，然后手动地在 Android 设备上 [安装 APK 文件][1]。
|
||||
|
||||
在非 Android 设备如常规的电脑和笔记本电脑上，有着几种方式来从 Google Play 商店下载到官方的 APK 文件。例如，使用浏览器插件(例如, 针对 [Chrome][2] 或针对 [Firefox][3] 的插件) 或利用允许你使用浏览器下载 APK 文件的在线的 APK 存档等。假如你不信任这些闭源的插件或第三方的 APK 仓库，这里有另一种手动下载官方 APK 文件的方法，它使用一个名为 [GooglePlayDownloader][4] 的开源 Linux 应用。
|
||||
|
||||
GooglePlayDownloader 是一个基于 Python 的 GUI 应用，使得你可以从 Google Play 商店上搜索和下载 APK 文件。由于它是完全开源的，你可以放心地使用它。在本篇教程中，我将展示如何在 Linux 环境下，使用 GooglePlayDownloader 来从 Google Play 商店下载 APK 文件。
|
||||
|
||||
### Python 需求 ###
|
||||
|
||||
GooglePlayDownloader 需要使用 Python 中 SSL 模块的扩展 SNI(服务器名称指示) 来支持 SSL/TLS 通信，该功能由 Python 2.7.9 或更高版本带来。这使得一些旧的发行版本如 Debian 7 Wheezy 及早期版本，Ubuntu 14.04 及早期版本或 CentOS/RHEL 7 及早期版本均不能满足该要求。假设你已经有了一个带有 Python 2.7.9 或更高版本的发行版本，可以像下面这样接着安装 GooglePlayDownloader。
|
||||
|
||||
### 在 Ubuntu 上安装 GooglePlayDownloader ###
|
||||
|
||||
在 Ubuntu 上，你可以使用官方构建的 deb 包。有一个条件是你可能需要手动地安装一个必需的依赖。
|
||||
|
||||
#### 在 Ubuntu 14.10 上 ####
|
||||
|
||||
下载 [python-ndg-httpsclient][5] deb 软件包，这在旧一点的 Ubuntu 发行版本中是一个缺失的依赖。同时还要下载 GooglePlayDownloader 的官方 deb 软件包。
|
||||
|
||||
$ wget http://mirrors.kernel.org/ubuntu/pool/main/n/ndg-httpsclient/python-ndg-httpsclient_0.3.2-1ubuntu4_all.deb
|
||||
$ wget http://codingteam.net/project/googleplaydownloader/download/file/googleplaydownloader_1.7-1_all.deb
|
||||
|
||||
如下所示，我们将使用 [gdebi 命令][6] 来安装这两个 deb 文件。 gedbi 命令将自动地处理任何其他的依赖。
|
||||
|
||||
$ sudo apt-get install gdebi-core
|
||||
$ sudo gdebi python-ndg-httpsclient_0.3.2-1ubuntu4_all.deb
|
||||
$ sudo gdebi googleplaydownloader_1.7-1_all.deb
|
||||
|
||||
#### 在 Ubuntu 15.04 或更新的版本上 ####
|
||||
|
||||
最近的 Ubuntu 发行版本上已经配备了所有需要的依赖，所以安装过程可以如下面那样直接进行。
|
||||
|
||||
$ wget http://codingteam.net/project/googleplaydownloader/download/file/googleplaydownloader_1.7-1_all.deb
|
||||
$ sudo apt-get install gdebi-core
|
||||
$ sudo gdebi googleplaydownloader_1.7-1_all.deb
|
||||
|
||||
### 在 Debian 上安装 GooglePlayDownloader ###
|
||||
|
||||
由于其 Python 需求， Googleplaydownloader 不能被安装到 Debian 7 Wheezy 或早期版本上，除非你升级了它自备的 Python 版本。
|
||||
|
||||
#### 在 Debian 8 Jessie 及更高版本上: ####
|
||||
|
||||
$ wget http://codingteam.net/project/googleplaydownloader/download/file/googleplaydownloader_1.7-1_all.deb
|
||||
$ sudo apt-get install gdebi-core
|
||||
$ sudo gdebi googleplaydownloader_1.7-1_all.deb
|
||||
|
||||
### 在 Fedora 上安装 GooglePlayDownloader ###
|
||||
|
||||
由于 GooglePlayDownloader 原本是针对基于 Debian 的发行版本所开发的，假如你想在 Fedora 上使用它，你需要从它的源码开始安装。
|
||||
|
||||
首先安装必需的依赖。
|
||||
|
||||
$ sudo yum install python-pyasn1 wxPython python-ndg_httpsclient protobuf-python python-requests
|
||||
|
||||
然后像下面这样安装它。
|
||||
|
||||
$ wget http://codingteam.net/project/googleplaydownloader/download/file/googleplaydownloader_1.7.orig.tar.gz
|
||||
$ tar -xvf googleplaydownloader_1.7.orig.tar.gz
|
||||
$ cd googleplaydownloader-1.7
|
||||
$ chmod o+r -R .
|
||||
$ sudo python setup.py install
|
||||
$ sudo sh -c "echo 'python /usr/lib/python2.7/site-packages/googleplaydownloader-1.7-py2.7.egg/googleplaydownloader/googleplaydownloader.py' > /usr/bin/googleplaydownloader"
|
||||
|
||||
### 使用 GooglePlayDownloader 从 Google Play 商店下载 APK 文件 ###
|
||||
|
||||
一旦你安装好 GooglePlayDownloader 后，你就可以像下面那样从 Google Play 商店下载 APK 文件。
|
||||
|
||||
首先通过输入下面的命令来启动该应用：
|
||||
|
||||
$ googleplaydownloader
|
||||
|
||||
|
||||
|
||||
在搜索栏中，输入你想从 Google Play 商店下载的应用的名称。
|
||||
|
||||
|
||||
|
||||
一旦你从搜索列表中找到了该应用，就选择该应用，接着点击 "下载选定的 APK 文件" 按钮。最后你将在你的家目录中找到下载的 APK 文件。现在，你就可以将下载到的 APK 文件转移到你所选择的 Android 设备上，然后手动安装它。
|
||||
|
||||
希望这篇教程对你有所帮助。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://xmodulo.com/download-apk-files-google-play-store.html
|
||||
|
||||
作者：[Dan Nanni][a]
|
||||
译者：[FSSlc](https://github.com/FSSlc)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://xmodulo.com/author/nanni
|
||||
[1]:http://xmodulo.com/how-to-install-apk-file-on-android-phone-or-tablet.html
|
||||
[2]:https://chrome.google.com/webstore/detail/apk-downloader/cgihflhdpokeobcfimliamffejfnmfii
|
||||
[3]:https://addons.mozilla.org/en-us/firefox/addon/apk-downloader/
|
||||
[4]:http://codingteam.net/project/googleplaydownloader
|
||||
[5]:http://packages.ubuntu.com/vivid/python-ndg-httpsclient
|
||||
[6]:http://xmodulo.com/how-to-install-deb-file-with-dependencies.html
|
||||
@ -0,0 +1,263 @@
|
||||
fdupes——Linux中查找并删除重复文件的命令行工具
|
||||
================================================================================
|
||||
对于大多数计算机用户而言，查找并替换重复的文件是一个常见的需求。查找并移除重复文件真是一项领人不胜其烦的工作，它耗时又耗力。如果你的机器上跑着GNU/Linux，那么查找重复文件会变得十分简单，这多亏了`**fdupes**`工具。
|
||||
|
||||
|
||||
|
||||
Fdupes——在Linux中查找并删除重复文件
|
||||
|
||||
### fdupes是啥东东？ ###
|
||||
|
||||
**Fdupes**是Linux下的一个工具，它由**Adrian Lopez**用C编程语言编写并基于MIT许可证发行，该应用程序可以在指定的目录及子目录中查找重复的文件。Fdupes通过对比文件的MD5签名，以及逐字节比较文件来识别重复内容，可以为Fdupes指定大量的选项以实现对文件的列出、删除、替换到文件副本的硬链接等操作。
|
||||
|
||||
对比以下列顺序开始：
|
||||
|
||||
**大小对比 > 部分 MD5 签名对比 > 完整 MD5 签名对比 > 逐字节对比**
|
||||
|
||||
### 安装 fdupes 到 Linux ###
|
||||
|
||||
在基于**Debian**的系统上，如**Ubuntu**和**Linux Mint**，安装最新版fdupes，用下面的命令手到擒来。
|
||||
|
||||
$ sudo apt-get install fdupes
|
||||
|
||||
在基于CentOS/RHEL和Fedora的系统上，你需要开启[epel仓库][1]来安装fdupes包。
|
||||
|
||||
# yum install fdupes
|
||||
# dnf install fdupes [On Fedora 22 onwards]
|
||||
|
||||
**注意**：自Fedora 22之后，默认的包管理器yum被dnf取代了。
|
||||
|
||||
### fdupes命令咋个搞？ ###
|
||||
1.作为演示的目的，让我们来在某个目录（比如 tecmint）下创建一些重复文件，命令如下：
|
||||
|
||||
$ mkdir /home/"$USER"/Desktop/tecmint && cd /home/"$USER"/Desktop/tecmint && for i in {1..15}; do echo "I Love Tecmint. Tecmint is a very nice community of Linux Users." > tecmint${i}.txt ; done
|
||||
|
||||
在执行以上命令后，让我们使用ls[命令][2]验证重复文件是否创建。
|
||||
|
||||
$ ls -l
|
||||
|
||||
total 60
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint10.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint11.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint12.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint13.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint14.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint15.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint1.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint2.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint3.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint4.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint5.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint6.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint7.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint8.txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9.txt
|
||||
|
||||
上面的脚本创建了**15**个文件，名称分别为tecmint1.txt，tecmint2.txt……tecmint15.txt，并且每个文件的数据相同，如
|
||||
|
||||
"I Love Tecmint. Tecmint is a very nice community of Linux Users."
|
||||
|
||||
2.现在在**tecmint**文件夹内搜索重复的文件。
|
||||
|
||||
$ fdupes /home/$USER/Desktop/tecmint
|
||||
|
||||
/home/tecmint/Desktop/tecmint/tecmint13.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint8.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint11.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint3.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint4.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint6.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint7.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint9.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint10.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint2.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint5.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint14.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint1.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint15.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint12.txt
|
||||
|
||||
3.使用**-r**选项在每个目录包括其子目录中递归搜索重复文件。
|
||||
|
||||
它会递归搜索所有文件和文件夹，花一点时间来扫描重复文件，时间的长短取决于文件和文件夹的数量。在此其间，终端中会显示全部过程，像下面这样。
|
||||
|
||||
$ fdupes -r /home
|
||||
|
||||
Progress [37780/54747] 69%
|
||||
|
||||
4.使用**-S**选项来查看某个文件夹内找到的重复文件的大小。
|
||||
|
||||
$ fdupes -S /home/$USER/Desktop/tecmint
|
||||
|
||||
65 bytes each:
|
||||
/home/tecmint/Desktop/tecmint/tecmint13.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint8.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint11.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint3.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint4.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint6.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint7.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint9.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint10.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint2.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint5.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint14.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint1.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint15.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint12.txt
|
||||
|
||||
5.你可以同时使用**-S**和**-r**选项来查看所有涉及到的目录和子目录中的重复文件的大小，如下：
|
||||
|
||||
$ fdupes -Sr /home/avi/Desktop/
|
||||
|
||||
65 bytes each:
|
||||
/home/tecmint/Desktop/tecmint/tecmint13.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint8.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint11.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint3.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint4.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint6.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint7.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint9.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint10.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint2.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint5.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint14.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint1.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint15.txt
|
||||
/home/tecmint/Desktop/tecmint/tecmint12.txt
|
||||
|
||||
107 bytes each:
|
||||
/home/tecmint/Desktop/resume_files/r-csc.html
|
||||
/home/tecmint/Desktop/resume_files/fc.html
|
||||
|
||||
6.不同于在一个或所有文件夹内递归搜索，你可以选择按要求有选择性地在两个或三个文件夹内进行搜索。不必再提醒你了吧，如有需要，你可以使用**-S**和/或**-r**选项。
|
||||
|
||||
$ fdupes /home/avi/Desktop/ /home/avi/Templates/
|
||||
|
||||
7.要删除重复文件，同时保留一个副本，你可以使用`**-d**`选项。使用该选项，你必须额外小心，否则最终结果可能会是文件/数据的丢失。郑重提醒，此操作不可恢复。
|
||||
|
||||
$ fdupes -d /home/$USER/Desktop/tecmint
|
||||
|
||||
[1] /home/tecmint/Desktop/tecmint/tecmint13.txt
|
||||
[2] /home/tecmint/Desktop/tecmint/tecmint8.txt
|
||||
[3] /home/tecmint/Desktop/tecmint/tecmint11.txt
|
||||
[4] /home/tecmint/Desktop/tecmint/tecmint3.txt
|
||||
[5] /home/tecmint/Desktop/tecmint/tecmint4.txt
|
||||
[6] /home/tecmint/Desktop/tecmint/tecmint6.txt
|
||||
[7] /home/tecmint/Desktop/tecmint/tecmint7.txt
|
||||
[8] /home/tecmint/Desktop/tecmint/tecmint9.txt
|
||||
[9] /home/tecmint/Desktop/tecmint/tecmint10.txt
|
||||
[10] /home/tecmint/Desktop/tecmint/tecmint2.txt
|
||||
[11] /home/tecmint/Desktop/tecmint/tecmint5.txt
|
||||
[12] /home/tecmint/Desktop/tecmint/tecmint14.txt
|
||||
[13] /home/tecmint/Desktop/tecmint/tecmint1.txt
|
||||
[14] /home/tecmint/Desktop/tecmint/tecmint15.txt
|
||||
[15] /home/tecmint/Desktop/tecmint/tecmint12.txt
|
||||
|
||||
Set 1 of 1, preserve files [1 - 15, all]:
|
||||
|
||||
你可能注意到了，所有重复的文件被列了出来，并给出删除提示，一个一个来，或者指定范围，或者一次性全部删除。你可以选择一个范围，就像下面这样，来删除指定范围内的文件。
|
||||
|
||||
Set 1 of 1, preserve files [1 - 15, all]: 2-15
|
||||
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint13.txt
|
||||
[+] /home/tecmint/Desktop/tecmint/tecmint8.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint11.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint3.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint4.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint6.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint7.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint9.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint10.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint2.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint5.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint14.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint1.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint15.txt
|
||||
[-] /home/tecmint/Desktop/tecmint/tecmint12.txt
|
||||
|
||||
8.从安全角度出发，你可能想要打印`**fdupes**`的输出结果到文件中，然后检查文本文件来决定要删除什么文件。这可以降低意外删除文件的风险。你可以这么做：
|
||||
|
||||
$ fdupes -Sr /home > /home/fdupes.txt
|
||||
|
||||
**注意**：你可以替换`**/home**`为你想要的文件夹。同时，如果你想要递归搜索并打印大小，可以使用`**-r**`和`**-S**`选项。
|
||||
|
||||
9.你可以使用`**-f**`选项来忽略每个匹配集中的首个文件。
|
||||
|
||||
首先列出该目录中的文件。
|
||||
|
||||
$ ls -l /home/$USER/Desktop/tecmint
|
||||
|
||||
total 20
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9 (3rd copy).txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9 (4th copy).txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9 (another copy).txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9 (copy).txt
|
||||
-rw-r--r-- 1 tecmint tecmint 65 Aug 8 11:22 tecmint9.txt
|
||||
|
||||
然后，忽略掉每个匹配集中的首个文件。
|
||||
|
||||
$ fdupes -f /home/$USER/Desktop/tecmint
|
||||
|
||||
/home/tecmint/Desktop/tecmint9 (copy).txt
|
||||
/home/tecmint/Desktop/tecmint9 (3rd copy).txt
|
||||
/home/tecmint/Desktop/tecmint9 (another copy).txt
|
||||
/home/tecmint/Desktop/tecmint9 (4th copy).txt
|
||||
|
||||
10.检查已安装的fdupes版本。
|
||||
|
||||
$ fdupes --version
|
||||
|
||||
fdupes 1.51
|
||||
|
||||
11.如果你需要关于fdupes的帮助，可以使用`**-h**`开关。
|
||||
|
||||
$ fdupes -h
|
||||
|
||||
Usage: fdupes [options] DIRECTORY...
|
||||
|
||||
-r --recurse for every directory given follow subdirectories
|
||||
encountered within
|
||||
-R --recurse: for each directory given after this option follow
|
||||
subdirectories encountered within (note the ':' at
|
||||
the end of the option, manpage for more details)
|
||||
-s --symlinks follow symlinks
|
||||
-H --hardlinks normally, when two or more files point to the same
|
||||
disk area they are treated as non-duplicates; this
|
||||
option will change this behavior
|
||||
-n --noempty exclude zero-length files from consideration
|
||||
-A --nohidden exclude hidden files from consideration
|
||||
-f --omitfirst omit the first file in each set of matches
|
||||
-1 --sameline list each set of matches on a single line
|
||||
-S --size show size of duplicate files
|
||||
-m --summarize summarize dupe information
|
||||
-q --quiet hide progress indicator
|
||||
-d --delete prompt user for files to preserve and delete all
|
||||
others; important: under particular circumstances,
|
||||
data may be lost when using this option together
|
||||
with -s or --symlinks, or when specifying a
|
||||
particular directory more than once; refer to the
|
||||
fdupes documentation for additional information
|
||||
-N --noprompt together with --delete, preserve the first file in
|
||||
each set of duplicates and delete the rest without
|
||||
prompting the user
|
||||
-v --version display fdupes version
|
||||
-h --help display this help message
|
||||
|
||||
到此为止了。让我知道你到现在为止你是怎么在Linux中查找并删除重复文件的？同时，也让我知道你关于这个工具的看法。在下面的评论部分中提供你有价值的反馈吧，别忘了为我们点赞并分享，帮助我们扩散哦。
|
||||
|
||||
我正在使用另外一个移除重复文件的工具，它叫**fslint**。很快就会把使用心得分享给大家哦，你们一定会喜欢看的。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/fdupes-find-and-delete-duplicate-files-in-linux/
|
||||
|
||||
作者：[GOLinux](https://github.com/GOLinux)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](http://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/avishek/
|
||||
[1]:http://www.tecmint.com/how-to-enable-epel-repository-for-rhel-centos-6-5/
|
||||
[2]:http://www.tecmint.com/15-basic-ls-command-examples-in-linux/
|
||||
@ -0,0 +1,258 @@
|
||||
RHCSA 系列：使用 Nano 和 Vim 编辑文本文件/使用 grep 和 regexps 分析文本 – Part 4
|
||||
================================================================================
|
||||
作为系统管理员的日常职责的一部分，每个系统管理员都必须处理文本文件，这包括编辑现存文件(大多可能是配置文件)，或创建新的文件。有这样一个说法，假如你想在 Linux 世界中挑起一场圣战，你可以询问系统管理员们，什么是他们最喜爱的编辑器以及为什么。在这篇文章中，我们并不打算那样做，但我们将向你呈现一些技巧，这些技巧对使用两款在 RHEL 7 中最为常用的文本编辑器: nano(由于其简单和易用，特别是对于新手来说) 和 vi/m(由于其自身的几个特色使得它不仅仅是一个简单的编辑器)来说都大有裨益。我确信你可以找到更多的理由来使用其中的一个或另一个，或许其他的一些编辑器如 emacs 或 pico。这完全取决于你。
|
||||
|
||||
|
||||
|
||||
RHCSA: 使用 Nano 和 Vim 编辑文本文件 – Part 4
|
||||
|
||||
### 使用 Nano 编辑器来编辑文件 ###
|
||||
|
||||
要启动 nano，你可以在命令提示符下输入 `nano`，或选择性地跟上一个文件名(在这种情况下，若文件存在，它将在编辑模式中被打开)。若文件不存在，或我们省略了文件名， nano 也将在 编辑模式下开启，但将为我们开启一个空白屏以便开始输入：
|
||||
|
||||
|
||||
|
||||
Nano 编辑器
|
||||
|
||||
正如你在上一张图片中所见的那样， nano 在屏幕的底部呈现出一些功能，它们可以通过暗指的快捷键来触发(^,即插入记号，代指 Ctrl 键)。它们中的一些是：
|
||||
|
||||
- Ctrl + G: 触发一个帮助菜单，带有一个关于功能和相应的描述的完整列表；
|
||||
- Ctrl + X: 离开当前文件，假如更改没有被保存，则它们将被丢弃；
|
||||
- Ctrl + R: 通过指定一个完整的文件路径，让你选择一个文件来将该文件的内容插入到当前文件中；
|
||||
|
||||
|
||||
|
||||
Nano 编辑器帮助菜单
|
||||
|
||||
- Ctrl + O: 保存更改到一个文件。它将让你用一个与源文件相同或不同的名称来保存该文件，然后按 Enter 键来确认。
|
||||
|
||||
|
||||
|
||||
Nano 编辑器的保存更改模式
|
||||
|
||||
- Ctrl + X: 离开当前文件，假如更改没有被保存，则它们将被丢弃；
|
||||
- Ctrl + R: 通过指定一个完整的文件路径，让你选择一个文件来将该文件的内容插入到当前文件中；
|
||||
|
||||
|
||||
|
||||
Nano: 插入文件内容到主文件中
|
||||
|
||||
上图的操作将把 `/etc/passwd` 的内容插入到当前文件中。
|
||||
|
||||
- Ctrl + K: 剪切当前行；
|
||||
- Ctrl + U: 粘贴；
|
||||
- Ctrl + C: 取消当前的操作并返回先前的屏幕；
|
||||
|
||||
为了轻松地在打开的文件中浏览， nano 提供了下面的功能：
|
||||
|
||||
- Ctrl + F 和 Ctrl + B 分别先前或向后移动光标；而 Ctrl + P 和 Ctrl + N 则分别向上或向下移动一行，功能与箭头键相同；
|
||||
- Ctrl + space 和 Alt + space 分别向前或向后移动一个单词；
|
||||
|
||||
最后，
|
||||
|
||||
- 假如你想将光标移动到文档中的特定位置，使用 Ctrl + _ (下划线) 并接着输入 X,Y 将准确地带你到 第 X 行，第 Y 列。
|
||||
|
||||
|
||||
|
||||
在 nano 中定位到具体的行和列
|
||||
|
||||
上面的例子将带你到当前文档的第 15 行，第 14 列。
|
||||
|
||||
假如你可以回忆起你早期的 Linux 岁月，特别是当你刚从 Windows 迁移到 Linux 中，你就可能会同意：对于一个新手来说，使用 nano 来开始学习是最好的方式。
|
||||
|
||||
### 使用 Vim 编辑器来编辑文件 ###
|
||||
|
||||
|
||||
Vim 是 vi 的加强版本，它是 Linux 中一个著名的文本编辑器，可在所有兼容 POSIX 的 *nix 系统中获取到，例如在 RHEL 7 中。假如你有机会并可以安装 Vim，请继续；假如不能，这篇文章中的大多数(若不是全部)的提示也应该可以正常工作。
|
||||
|
||||
Vim 的一个出众的特点是可以在多个不同的模式中进行操作：
|
||||
|
||||
- 命令模式将允许你在文件中跳转和输入命令，这些命令是由一个或多个字母组成的简洁且对大小写敏感的组合。假如你想重复执行某个命令特定次，你可以在这个命令前加上需要重复的次数(这个规则只有极少数例外)。例如， yy(或 Y，yank 的缩写)可以复制整个当前行，而 4yy(或 4Y)则复制整个当前行到接着的 3 行(总共 4 行)。
|
||||
- 在 ex 模式中，你可以操作文件(包括保存当前文件和运行外部的程序或命令)。要进入 ex 模式，你必须在命令模式前(或其他词前，Esc + ：)输入一个冒号(:)，再直接跟上你想使用的 ex 模式命令的名称。
|
||||
- 对于插入模式，可以输入字母 i 进入，我们只需要输入文字即可。大多数的键击结果都将出现在屏幕中的文本中。
|
||||
- 我们总是可以通过敲击 Esc 键来进入命令模式(无论我们正工作在哪个模式下)。
|
||||
|
||||
现在，让我们看看如何在 vim 中执行在上一节列举的针对 nano 的相同的操作。不要忘记敲击 Enter 键来确认 vim 命令。
|
||||
|
||||
为了从命令行中获取 vim 的完整手册，在命令模式下键入 `:help` 并敲击 Enter 键：
|
||||
|
||||
|
||||
|
||||
vim 编辑器帮助菜单
|
||||
|
||||
上面的小节呈现出一个目录列表，而定义过的小节则主要关注 Vim 的特定话题。要浏览某一个小节，可以将光标放到它的上面，然后按 Ctrl + ] (闭方括号)。注意，底部的小节展示的是当前文件的内容。
|
||||
|
||||
1. 要保存更改到文件，在命令模式中运行下面命令中的任意一个，就可以达到这个目的：
|
||||
|
||||
```
|
||||
:wq!
|
||||
:x!
|
||||
ZZ (是的，两个 ZZ,前面无需添加冒号)
|
||||
```
|
||||
|
||||
2. 要离开并丢弃更改，使用 `:q!`。这个命令也将允许你离开上面描述过的帮助菜单，并返回到命令模式中的当前文件。
|
||||
|
||||
3. 剪切 N 行：在命令模式中键入 `Ndd`。
|
||||
|
||||
4. 复制 M 行：在命令模式中键入 `Myy`。
|
||||
|
||||
5. 粘贴先前剪贴或复制过的行：在命令模式中按 `P`键。
|
||||
|
||||
6. 要插入另一个文件的内容到当前文件：
|
||||
|
||||
:r filename
|
||||
|
||||
例如，插入 `/etc/fstab` 的内容，可以这样做：
|
||||
|
||||
[在 vi 编辑器中插入文件的内容](http://www.tecmint.com/wp-content/uploads/2015/03/Insert-Content-vi-Editor.png)
|
||||
|
||||
在 vi 编辑器中插入文件的内容
|
||||
|
||||
7. 插入一个命名的输出到当前文档：
|
||||
|
||||
:r! command
|
||||
|
||||
例如，要在光标所在的当前位置后面插入日期和时间：
|
||||
|
||||
|
||||
|
||||
在 vi 编辑器中插入时间和日期
|
||||
|
||||
在另一篇我写的文章中，([LFCS 系列的 Part 2][1])，我更加详细地解释了在 vim 中可用的键盘快捷键和功能。或许你可以参考那个教程来查看如何使用这个强大的文本编辑器的更深入的例子。
|
||||
|
||||
### 使用 Grep 和正则表达式来分析文本 ###
|
||||
|
||||
到现在为止，你已经学习了如何使用 nano 或 vim 创建和编辑文件。打个比方说，假如你成为了一个文本编辑器忍者 – 那又怎样呢？ 在其他事情上，你也需要知道如何在文本中搜索正则表达式。
|
||||
|
||||
正则表达式(也称为 "regex" 或 "regexp") 是一种识别一个特定文本字符串或模式的方式，使得一个程序可以将这个模式和任意的文本字符串相比较。尽管利用 grep 来使用正则表达式值得用一整篇文章来描述，这里就让我们复习一些基本的知识：
|
||||
|
||||
**1. 最简单的正则表达式是一个由数字和字母构成的字符串(即，单词 "svm") 或两个(在使用两个字符串时，你可以使用 `|`(或) 操作符)：**
|
||||
|
||||
# grep -Ei 'svm|vmx' /proc/cpuinfo
|
||||
|
||||
上面命令的输出结果中若有这两个字符串之一的出现，则标志着你的处理器支持虚拟化:
|
||||
|
||||
|
||||
|
||||
正则表达式示例
|
||||
|
||||
**2. 第二种正则表达式是一个范围列表，由方括号包裹。**
|
||||
|
||||
例如， `c[aeiou]t` 匹配字符串 cat,cet,cit,cot 和 cut，而 `[a-z]` 和 `[0-9]` 则相应地匹配小写字母或十进制数字。假如你想重复正则表达式 X 次，在正则表达式的后面立即输入 `{X}`即可。
|
||||
|
||||
例如，让我们从 `/etc/fstab` 中析出存储设备的 UUID：
|
||||
|
||||
# grep -Ei '[0-9a-f]{8}-([0-9a-f]{4}-){3}[0-9a-f]{12}' -o /etc/fstab
|
||||
|
||||
|
||||
|
||||
从一个文件中析出字符串
|
||||
|
||||
方括号中的第一个表达式 `[0-9a-f]` 被用来表示小写的十六进制字符，`{8}`是一个量词，暗示前面匹配的字符串应该重复的次数(在一个 UUID 中的开头序列是一个 8 个字符长的十六进制字符串)。
|
||||
|
||||
在圆括号中，量词 `{4}`和连字符暗示下一个序列是一个 4 个字符长的十六进制字符串，接着的量词 `({3})`表示前面的表达式要重复 3 次。
|
||||
|
||||
最后，在 UUID 中的最后一个 12 个字符长的十六进制字符串可以由 `[0-9a-f]{12}` 取得， `-o` 选项表示只打印出在 `/etc/fstab`中匹配行中的匹配的(非空)部分。
|
||||
|
||||
**3. POSIX 字符类 **
|
||||
|
||||
注：表格
|
||||
<table cellspacing="0" border="0">
|
||||
<colgroup width="201"></colgroup>
|
||||
<colgroup width="440"></colgroup>
|
||||
<tbody>
|
||||
<tr>
|
||||
<td align="center" height="25" bgcolor="#999999" style="border: 1px solid #000000;"><b>字符类</b></td>
|
||||
<td align="center" bgcolor="#999999" style="border: 1px solid #000000;"><b>匹配 …</b></td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:alnum:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意字母或数字 [a-zA-Z0-9] </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:alpha:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意字母 [a-zA-Z] </td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:blank:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 空格或制表符</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:cntrl:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意控制字符 (ASCII 码的 0 至 32)</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:digit:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意数字 [0-9]</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:graph:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意可见字符</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:lower:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意小写字母 [a-z] </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:print:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意非控制字符 <td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:space:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意空格</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:punct:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意标点字符</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:upper:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意大写字母 [A-Z] </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [[:xdigit:]]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意十六进制数字 [0-9a-fA-F]</td>
|
||||
</tr>
|
||||
<tr class="alt">
|
||||
<td align="left" height="21" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> [:word:]</td>
|
||||
<td align="left" bgcolor="#FFFFFF" style="border: 1px solid #000000;"> 任意字母，数字和下划线 [a-zA-Z0-9_]</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
|
||||
例如，我们可能会对查找已添加到我们系统中给真实用户的 UID 和 GID(参考这个系列的 [Part 2][2]来回忆起这些知识)感兴趣。那么，我们将在 `/etc/passwd` 文件中查找 4 个字符长的序列：
|
||||
|
||||
# grep -Ei [[:digit:]]{4} /etc/passwd
|
||||
|
||||
|
||||
|
||||
在文件中查找一个字符串
|
||||
|
||||
上面的示例可能不是真实世界中使用正则表达式的最好案例，但它清晰地启发了我们如何使用 POSIX 字符类来使用 grep 分析文本。
|
||||
|
||||
### 总结 ###
|
||||
|
||||
|
||||
在这篇文章中，我们已经提供了一些技巧来最大地利用针对命令行用户的两个文本编辑器 nano 和 vim，这两个工具都有相关的扩展文档可供阅读，你可以分别查询它们的官方网站(链接在下面给出)以及使用这个系列中的 [Part 1][3] 给出的建议。
|
||||
|
||||
#### 参考文件链接 ####
|
||||
|
||||
- [http://www.nano-editor.org/][4]
|
||||
- [http://www.vim.org/][5]
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/rhcsa-exam-how-to-use-nano-vi-editors/
|
||||
|
||||
作者：[Gabriel Cánepa][a]
|
||||
译者：[FSSlc](https://github.com/FSSlc)
|
||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
|
||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://www.tecmint.com/author/gacanepa/
|
||||
[1]:http://www.tecmint.com/vi-editor-usage/
|
||||
[2]:http://www.tecmint.com/file-and-directory-management-in-linux/
|
||||
[3]:http://www.tecmint.com/rhcsa-exam-reviewing-essential-commands-system-documentation/
|
||||
[4]:http://www.nano-editor.org/
|
||||
[5]:http://www.vim.org/
|
||||
Loading…
Reference in New Issue
Block a user