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Linux问答 -- 如何在Linux上安装Git
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Linux有问必答：如何在Linux上安装Git
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================================================================================
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> **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]?
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> **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？
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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。
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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。
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### 使用包管理器安装Git ###
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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。
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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。
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**Debian, Ubuntu, 或 Linux Mint**
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@ -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
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**Fedora, CentOS 或 RHEL**
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$ sudo yum install git
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或
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$ sudo dnf install git
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**Arch Linux**
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@ -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
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### 从源码安装Git ###
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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。
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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。
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**安装依赖包**
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@ -65,7 +67,7 @@ via: http://ask.xmodulo.com/install-git-linux.html
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作者：[Dan Nanni][a]
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译者：[mr-ping](https://github.com/mr-ping)
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校对：[校对者ID](https://github.com/校对者ID)
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校对：[wxy](https://github.com/wxy)
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|
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
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61
published/20150810 For Linux, Supercomputers R Us.md
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61
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有了 Linux，你就可以搭建自己的超级计算机
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================================================================================
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> 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。
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*题图来源：By Michel Ngilen,[ CC BY 2.0 ], via Wikimedia Commons*
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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！
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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。
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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。
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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。
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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]。
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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。
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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]。
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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。
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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。
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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]。
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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。
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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。
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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。
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||||
--------------------------------------------------------------------------------
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||||
|
||||
via: http://www.computerworld.com/article/2960701/linux/for-linux-supercomputers-r-us.html
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|
||||
作者：[Steven J. Vaughan-Nichols][a]
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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
|
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|
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[a]:http://www.computerworld.com/author/Steven-J.-Vaughan_Nichols/
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[1]:http://www.top500.org/
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[2]:http://www.zdnet.com/article/build-your-own-supercomputer-out-of-raspberry-pi-boards/
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[3]:https://www.raspberrypi.org/products/model-b/
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[4]:http://www.zdnet.com/article/linux-still-rules-supercomputing/
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[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
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[6]:http://www.computerworld.com/article/2529932/cybercrime-hacking/researchers-hack-verisign-s-ssl-scheme-for-securing-web-sites.html
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[7]:http://phys.org/news/2010-12-air-playstation-3s-supercomputer.html
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[8]:http://www.zdnet.com/article/parallella-the-99-linux-supercomputer/
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[9]:http://blogs.nvidia.com/blog/2014/03/25/titan-z/
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[10]:http://www.amd.com/en-us/press-releases/Pages/amd-flagship-professional-2014apr7.aspx
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[11]:http://en.intelextrememasters.com/news/check-out-the-intel-extreme-masters-katowice-prize-money-distribution/
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|
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[13]:http://www.beowulf.org/overview/history.html
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[14]:http://yclept.ucdavis.edu/Beowulf/aboutbeowulf.html
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[15]:http://www.beowulf.org/
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@ -1,100 +0,0 @@
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Translating by ZTinoZ
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5 heroes of the Linux world
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================================================================================
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Who are these people, seen and unseen, whose work affects all of us every day?
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Image courtesy [Christopher Michel/Flickr][1]
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### High-flying penguins ###
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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.)
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Who are these people? These heroes of the Linux world, whose work affects all of us every day. Allow me to introduce you.
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Image courtesy Swapnil Bhartiya
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### Klaus Knopper ###
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Klaus Knopper, an Austrian developer who lives in Germany, is the founder of Knoppix and Adriana Linux, which he developed for his blind wife.
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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.
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Image courtesy [Fórum Internacional Software Live/Flickr][2]
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### Lennart Pottering ###
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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.
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Pottering wrote the modern init system systemd, which shook the Linux world and created a [rift in the Debian community][3].
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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].
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Lennart is also the author of Pulseaudio, sound server on Linux and Avahi, zero-configuration networking (zeroconf) implementation.
|
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|
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|
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Image courtesy [Meego Com/Flickr][5]
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### Jim Zemlin ###
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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.
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|
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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.
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|
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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.
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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].
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People may think of Zemlin as Linus Torvalds' boss, but he refers to himself as "Linus Torvalds' janitor."
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Image courtesy [Coscup/Flickr][7]
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### Greg Kroah-Hartman ###
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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.
|
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|
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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.)
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Kroah-Hartman previously worked for Novell and then joined the Linux Foundation as a fellow, alongside Linus Torvalds.
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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].
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On a personal level, Kroah-Hartman is extremely helpful to new developers and users and is easily accessible.
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Image courtesy Swapnil Bhartiya
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### Linus Torvalds ###
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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.
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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.
|
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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.
|
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|
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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
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[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
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||||
[7]:https://flic.kr/p/hBv8Pp
|
||||
[8]:https://en.wikipedia.org/wiki/Sysfs
|
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[9]:https://www.youtube.com/watch?v=CyHAeGBFS8k
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[10]:http://www.itworld.com/article/2873200/operating-systems/11-technologies-that-tick-off-linus-torvalds.html
|
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@ -1,60 +0,0 @@
|
||||
Translating by xiaoyu33
|
||||
For Linux, Supercomputers R Us
|
||||
================================================================================
|
||||
|
||||
Credit: Michel Ngilen, CC BY 2.0, via Wikimedia Commons
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|
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> Almost all supercomputers run Linux, including the ones built from Raspberry Pi boards and PlayStation 3 game consoles
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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.
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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.
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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.
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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.
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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].
|
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|
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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.
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|
||||
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/
|
||||
@ -1,117 +0,0 @@
|
||||
translation by strugglingyouth
|
||||
Troubleshooting with Linux Logs
|
||||
================================================================================
|
||||
Troubleshooting is the main reason people create logs. Often you’ll want to diagnose why a problem happened with your Linux system or application. An error message or a sequence of events can give you clues to the root cause, indicate how to reproduce the issue, and point out ways to fix it. Here are a few use cases for things you might want to troubleshoot in your logs.
|
||||
|
||||
### Cause of Login Failures ###
|
||||
|
||||
If you want to check if your system is secure, you can check your authentication logs for failed login attempts and unfamiliar successes. Authentication failures occur when someone passes incorrect or otherwise invalid login credentials, often to ssh for remote access or su for local access to another user’s permissions. These are logged by the [pluggable authentication module][1], or pam for short. Look in your logs for strings like Failed password and user unknown. Successful authentication records include strings like Accepted password and session opened.
|
||||
|
||||
Failure Examples:
|
||||
|
||||
pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=10.0.2.2
|
||||
Failed password for invalid user hoover from 10.0.2.2 port 4791 ssh2
|
||||
pam_unix(sshd:auth): check pass; user unknown
|
||||
PAM service(sshd) ignoring max retries; 6 > 3
|
||||
|
||||
Success Examples:
|
||||
|
||||
Accepted password for hoover from 10.0.2.2 port 4792 ssh2
|
||||
pam_unix(sshd:session): session opened for user hoover by (uid=0)
|
||||
pam_unix(sshd:session): session closed for user hoover
|
||||
|
||||
You can use grep to find which users accounts have the most failed logins. These are the accounts that potential attackers are trying and failing to access. This example is for an Ubuntu system.
|
||||
|
||||
$ grep "invalid user" /var/log/auth.log | cut -d ' ' -f 10 | sort | uniq -c | sort -nr
|
||||
23 oracle
|
||||
18 postgres
|
||||
17 nagios
|
||||
10 zabbix
|
||||
6 test
|
||||
|
||||
You’ll need to write a different command for each application and message because there is no standard format. Log management systems that automatically parse logs will effectively normalize them and help you extract key fields like username.
|
||||
|
||||
Log management systems can extract the usernames from your Linux logs using automated parsing. This lets you see an overview of the users and filter on them with a single click. In this example, we can see that the root user logged in over 2,700 times because we are filtering the logs to show login attempts only for the root user.
|
||||
|
||||
|
||||
|
||||
Log management systems also let you view graphs over time to spot unusual trends. If someone had one or two failed logins within a few minutes, it might be that a real user forgot his or her password. However, if there are hundreds of failed logins or they are all different usernames, it’s more likely that someone is trying to attack the system. Here you can see that on March 12, someone tried to login as test and nagios several hundred times. This is clearly not a legitimate use of the system.
|
||||
|
||||
|
||||
|
||||
### Cause of Reboots ###
|
||||
|
||||
Sometimes a server can stop due to a system crash or reboot. How do you know when it happened and who did it?
|
||||
|
||||
#### Shutdown Command ####
|
||||
|
||||
If someone ran the shutdown command manually, you can see it in the auth log file. Here you can see that someone remotely logged in from the IP 50.0.134.125 as the user ubuntu and then shut the system down.
|
||||
|
||||
Mar 19 18:36:41 ip-172-31-11-231 sshd[23437]: Accepted publickey for ubuntu from 50.0.134.125 port 52538 ssh
|
||||
Mar 19 18:36:41 ip-172-31-11-231 23437]:sshd[ pam_unix(sshd:session): session opened for user ubuntu by (uid=0)
|
||||
Mar 19 18:37:09 ip-172-31-11-231 sudo: ubuntu : TTY=pts/1 ; PWD=/home/ubuntu ; USER=root ; COMMAND=/sbin/shutdown -r now
|
||||
|
||||
#### Kernel Initializing ####
|
||||
|
||||
If you want to see when the server restarted regardless of reason (including crashes) you can search logs from the kernel initializing. You’d search for the facility kernel messages and Initializing cpu.
|
||||
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Initializing cgroup subsys cpuset
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Initializing cgroup subsys cpu
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Linux version 3.8.0-44-generic (buildd@tipua) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #66~precise1-Ubuntu SMP Tue Jul 15 04:01:04 UTC 2014 (Ubuntu 3.8.0-44.66~precise1-generic 3.8.13.25)
|
||||
|
||||
### Detect Memory Problems ###
|
||||
|
||||
There are lots of reasons a server might crash, but one common cause is running out of memory.
|
||||
|
||||
When your system is low on memory, processes are killed, typically in the order of which ones will release the most resources. The error occurs when your system is using all of its memory and a new or existing process attempts to access additional memory. Look in your log files for strings like Out of Memory or for kernel warnings like to kill. These strings indicate that your system intentionally killed the process or application rather than allowing the process to crash.
|
||||
|
||||
Examples:
|
||||
|
||||
[33238.178288] Out of memory: Kill process 6230 (firefox) score 53 or sacrifice child
|
||||
[29923450.995084] select 5230 (docker), adj 0, size 708, to kill
|
||||
|
||||
You can find these logs using a tool like grep. This example is for Ubuntu:
|
||||
|
||||
$ grep “Out of memory” /var/log/syslog
|
||||
[33238.178288] Out of memory: Kill process 6230 (firefox) score 53 or sacrifice child
|
||||
|
||||
Keep in mind that grep itself uses memory, so you might cause an out of memory error just by running grep. This is another reason it’s a fabulous idea to centralize your logs!
|
||||
|
||||
### Log Cron Job Errors ###
|
||||
|
||||
The cron daemon is a scheduler that runs processes at specified dates and times. If the process fails to run or fails to finish, then a cron error appears in your log files. You can find these files in /var/log/cron, /var/log/messages, and /var/log/syslog depending on your distribution. There are many reasons a cron job can fail. Usually the problems lie with the process rather than the cron daemon itself.
|
||||
|
||||
By default, cron jobs output through email using Postfix. Here is a log showing that an email was sent. Unfortunately, you cannot see the contents of the message here.
|
||||
|
||||
Mar 13 16:35:01 PSQ110 postfix/pickup[15158]: C3EDC5800B4: uid=1001 from=<hoover>
|
||||
Mar 13 16:35:01 PSQ110 postfix/cleanup[15727]: C3EDC5800B4: message-id=<20150310110501.C3EDC5800B4@PSQ110>
|
||||
Mar 13 16:35:01 PSQ110 postfix/qmgr[15159]: C3EDC5800B4: from=<hoover@loggly.com>, size=607, nrcpt=1 (queue active)
|
||||
Mar 13 16:35:05 PSQ110 postfix/smtp[15729]: C3EDC5800B4: to=<hoover@loggly.com>, relay=gmail-smtp-in.l.google.com[74.125.130.26]:25, delay=4.1, delays=0.26/0/2.2/1.7, dsn=2.0.0, status=sent (250 2.0.0 OK 1425985505 f16si501651pdj.5 - gsmtp)
|
||||
|
||||
You should consider logging the cron standard output to help debug problems. Here is how you can redirect your cron standard output to syslog using the logger command. Replace the echo command with your own script and helloCron with whatever you want to set the appName to.
|
||||
|
||||
*/5 * * * * echo ‘Hello World’ 2>&1 | /usr/bin/logger -t helloCron
|
||||
|
||||
Which creates the log entries:
|
||||
|
||||
Apr 28 22:20:01 ip-172-31-11-231 CRON[15296]: (ubuntu) CMD (echo 'Hello World!' 2>&1 | /usr/bin/logger -t helloCron)
|
||||
Apr 28 22:20:01 ip-172-31-11-231 helloCron: Hello World!
|
||||
|
||||
Each cron job will log differently based on the specific type of job and how it outputs data. Hopefully there are clues to the root cause of problems within the logs, or you can add additional logging as needed.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.loggly.com/ultimate-guide/logging/troubleshooting-with-linux-logs/
|
||||
|
||||
作者：[Jason Skowronski][a1]
|
||||
作者：[Amy Echeverri][a2]
|
||||
作者：[Sadequl Hussain][a3]
|
||||
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
|
||||
|
||||
[a1]:https://www.linkedin.com/in/jasonskowronski
|
||||
[a2]:https://www.linkedin.com/in/amyecheverri
|
||||
[a3]:https://www.linkedin.com/pub/sadequl-hussain/14/711/1a7
|
||||
[1]:http://linux.die.net/man/8/pam.d
|
||||
@ -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 +1,62 @@
|
||||
Darkstat is a Web Based Network Traffic Analyzer – Install it on Linux
|
||||
================================================================================
|
||||
Darkstat is a simple, web based network traffic analyzer application. It works on many popular operating systems like Linux, Solaris, Mac and AIX. It keeps running in the background as a daemon and continues collecting and sniffing network data and presents it in easily understandable format within its web interface. It can generate traffic reports for hosts, identify which ports are open on some particular host and is IPV 6 complaint application. Let’s see how we can install and configure it on Linux operating system.
|
||||
|
||||
### Installing Darkstat on Linux ###
|
||||
|
||||
**Install Darkstat on Fedora/CentOS/RHEL:**
|
||||
|
||||
In order to install it on Fedora/RHEL and CentOS Linux distributions, run following command on the terminal.
|
||||
|
||||
sudo yum install darkstat
|
||||
|
||||
**Install Darkstat on Ubuntu/Debian:**
|
||||
|
||||
Run following on the terminal to install it on Ubuntu and Debian.
|
||||
|
||||
sudo apt-get install darkstat
|
||||
|
||||
Congratulations, Darkstat has been installed on your Linux system now.
|
||||
|
||||
### Configuring Darkstat ###
|
||||
|
||||
In order to run this application properly, we need to perform some basic configurations. Edit /etc/darkstat/init.cfg file in Gedit text editor by running the following command on the terminal.
|
||||
|
||||
sudo gedit /etc/darkstat/init.cfg
|
||||
|
||||
|
||||
Edit Darkstat
|
||||
|
||||
Change START_DARKSTAT parameter to “yes” and provide your network interface in “INTERFACE”. Make sure to uncomment DIR, PORT, BINDIP, and LOCAL parameters here. If you wish to bind the web interface for Darkstat to some specific IP, provide it in BINDIP section.
|
||||
|
||||
### Starting Darkstat Daemon ###
|
||||
|
||||
Once the installation and configuration for Darkstat is complete, run following command to start its daemon.
|
||||
|
||||
sudo /etc/init.d/darkstat start
|
||||
|
||||
|
||||
|
||||
You can configure Darkstat to start on system boot by running the following command:
|
||||
|
||||
chkconfig darkstat on
|
||||
|
||||
Launch your browser and load **http://localhost:666** and it will display the web based graphical interface for Darkstat. Start using this tool to analyze your network traffic.
|
||||
|
||||
|
||||
|
||||
### Conclusion ###
|
||||
|
||||
It is a lightweight tool with very low memory footprints. The key reason for the popularity of this tool is simplicity, ease of configuration and usage. It is a must-have application for System and Network Administrators.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://linuxpitstop.com/install-darkstat-on-ubuntu-linux/
|
||||
|
||||
作者：[Aun][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](http://linux.cn/) 荣誉推出
|
||||
|
||||
[a]:http://linuxpitstop.com/author/aun/
|
||||
@ -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 +1,101 @@
|
||||
FSSlc translating
|
||||
|
||||
How to download apk files from Google Play Store on Linux
|
||||
================================================================================
|
||||
Suppose you want to install an Android app on your Android device. However, for whatever reason, you cannot access Google Play Store on the Android device. What can you do then? One way to install the app without Google Play Store access is to download its APK file using some other means, and then [install the APK][1] file on the Android device manually.
|
||||
|
||||
There are several ways to download official APK files from Google Play Store on non-Android devices such as regular computers and laptops. For example, there are browser plugins (e.g., for [Chrome][2] or [Firefox][3]) or online APK archives that allow you to download APK files using a web browser. If you do not trust these closed-source plugins or third-party APK repositories, there is yet another way to download official APK files manually, and that is via an open-source Linux app called [GooglePlayDownloader][4].
|
||||
|
||||
GooglePlayDownloader is a Python-based GUI application that enables you to search and download APK files from Google Play Store. Since this is completely open-source, you can be assured while using it. In this tutorial, I am going to show how to download an APK file from Google Play Store using GooglePlayDownloader in Linux environment.
|
||||
|
||||
### Python requirement ###
|
||||
|
||||
GooglePlayDownloader requires Python with SNI (Server Name Indication) support for SSL/TLS communication. This feature comes with Python 2.7.9 or higher. This leaves out older distributions such as Debian 7 Wheezy or earlier, Ubuntu 14.04 or earlier, or CentOS/RHEL 7 or earlier. Assuming that you have a Linux distribution with Python 2.7.9 or higher, proceed to install GooglePlayDownloader as follows.
|
||||
|
||||
### Install GooglePlayDownloader on Ubuntu ###
|
||||
|
||||
On Ubuntu, you can use the official deb build. One catch is that you may need to install one required dependency manually.
|
||||
|
||||
#### On Ubuntu 14.10 ####
|
||||
|
||||
Download [python-ndg-httpsclient][5] deb package, which is a missing dependency on older Ubuntu distributions. Also download GooglePlayDownloader's official deb package.
|
||||
|
||||
$ 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
|
||||
|
||||
We are going to use [gdebi command][6] to install those two deb files as follows. The gdebi command will automatically handle any other dependencies.
|
||||
|
||||
$ 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
|
||||
|
||||
#### On Ubuntu 15.04 or later ####
|
||||
|
||||
Recent Ubuntu distributions ship all required dependencies, and thus the installation is straightforward as follows.
|
||||
|
||||
$ 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
|
||||
|
||||
### Install GooglePlayDownloader on Debian ###
|
||||
|
||||
Due to its Python requirement, GooglePlayDownloader cannot be installed on Debian 7 Wheezy or earlier unless you upgrade its stock Python.
|
||||
|
||||
#### On Debian 8 Jessie and higher: ####
|
||||
|
||||
$ 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
|
||||
|
||||
### Install GooglePlayDownloader on Fedora ###
|
||||
|
||||
Since GooglePlayDownloader was originally developed for Debian based distributions, you need to install it from the source if you want to use it on Fedora.
|
||||
|
||||
First, install necessary dependencies.
|
||||
|
||||
$ sudo yum install python-pyasn1 wxPython python-ndg_httpsclient protobuf-python python-requests
|
||||
|
||||
Then install it as follows.
|
||||
|
||||
$ 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"
|
||||
|
||||
### Download APK Files from Google Play Store with GooglePlayDownloader ###
|
||||
|
||||
Once you installed GooglePlayDownloader, you can download APK files from Google Play Store as follows.
|
||||
|
||||
First launch the app by typing:
|
||||
|
||||
$ googleplaydownloader
|
||||
|
||||
|
||||
|
||||
At the search bar, type the name of the app you want to download from Google Play Store.
|
||||
|
||||
|
||||
|
||||
Once you find the app in the search list, choose the app, and click on "Download selected APK(s)" button. You will find the downloaded APK file in your home directory. Now you can move the APK file to the Android device of your choice, and install it manually.
|
||||
|
||||
Hope this helps.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://xmodulo.com/download-apk-files-google-play-store.html
|
||||
|
||||
作者：[Dan Nanni][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/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 +1,265 @@
|
||||
fdupes – A Comamndline Tool to Find and Delete Duplicate Files in Linux
|
||||
================================================================================
|
||||
It is a common requirement to find and replace duplicate files for most of the computer users. Finding and removing duplicate files is a tiresome job that demands time and patience. Finding duplicate files can be very easy if your machine is powered by GNU/Linux, thanks to ‘**fdupes**‘ utility.
|
||||
|
||||
|
||||
|
||||
Fdupes – Find and Delete Duplicate Files in Linux
|
||||
|
||||
### What is fdupes? ###
|
||||
|
||||
**Fdupes** is a Linux utility written by **Adrian Lopez** in C programming Language released under MIT License. The application is able to find duplicate files in the given set of directories and sub-directories. Fdupes recognize duplicates by comparing MD5 signature of files followed by a byte-to-byte comparison. A lots of options can be passed with Fdupes to list, delete and replace the files with hardlinks to duplicates.
|
||||
|
||||
The comparison starts in the order:
|
||||
|
||||
**size comparison > Partial MD5 Signature Comparison > Full MD5 Signature Comparison > Byte-to-Byte Comparison.**
|
||||
|
||||
### Install fdupes on a Linux ###
|
||||
|
||||
Installation of latest version of fdupes (fdupes version 1.51) as easy as running following command on **Debian** based systems such as **Ubuntu** and **Linux Mint**.
|
||||
|
||||
$ sudo apt-get install fdupes
|
||||
|
||||
On CentOS/RHEL and Fedora based systems, you need to turn on [epel repository][1] to install fdupes package.
|
||||
|
||||
# yum install fdupes
|
||||
# dnf install fdupes [On Fedora 22 onwards]
|
||||
|
||||
**Note**: The default package manager yum is replaced by dnf from Fedora 22 onwards…
|
||||
|
||||
### How to use fdupes command? ###
|
||||
|
||||
1. For demonstration purpose, let’s a create few duplicate files under a directory (say tecmint) simply as:
|
||||
|
||||
$ 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
|
||||
|
||||
After running above command, let’s verify the duplicates files are created or not using ls [command][2].
|
||||
|
||||
$ 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
|
||||
|
||||
The above script create **15** files namely tecmint1.txt, tecmint2.txt…tecmint15.txt and every files contains the same data i.e.,
|
||||
|
||||
"I Love Tecmint. Tecmint is a very nice community of Linux Users."
|
||||
|
||||
2. Now search for duplicate files within the folder **tecmint**.
|
||||
|
||||
$ 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. Search for duplicates recursively under every directory including it’s sub-directories using the **-r** option.
|
||||
|
||||
It search across all the files and folder recursively, depending upon the number of files and folders it will take some time to scan duplicates. In that mean time, you will be presented with the total progress in terminal, something like this.
|
||||
|
||||
$ fdupes -r /home
|
||||
|
||||
Progress [37780/54747] 69%
|
||||
|
||||
4. See the size of duplicates found within a folder using the **-S** option.
|
||||
|
||||
$ 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. You can see the size of duplicate files for every directory and subdirectories encountered within using the **-S** and **-r** options at the same time, as:
|
||||
|
||||
$ 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. Other than searching in one folder or all the folders recursively, you may choose to choose in two folders or three folders as required. Not to mention you can use option **-S** and/or **-r** if required.
|
||||
|
||||
$ fdupes /home/avi/Desktop/ /home/avi/Templates/
|
||||
|
||||
7. To delete the duplicate files while preserving a copy you can use the option ‘**-d**’. Extra care should be taken while using this option else you might end up loosing necessary files/data and mind it the process is unrecoverable.
|
||||
|
||||
$ 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]:
|
||||
|
||||
You may notice that all the duplicates are listed and you are prompted to delete, either one by one or certain range or all in one go. You may select a range something like below to delete files files of specific range.
|
||||
|
||||
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. From safety point of view, you may like to print the output of ‘**fdupes**’ to file and then check text file to decide what file to delete. This decrease chances of getting your file deleted accidentally. You may do:
|
||||
|
||||
$ fdupes -Sr /home > /home/fdupes.txt
|
||||
|
||||
**Note**: You may replace ‘**/home**’ with the your desired folder. Also use option ‘**-r**’ and ‘**-S**’ if you want to search recursively and Print Size, respectively.
|
||||
|
||||
9. You may omit the first file from each set of matches by using option ‘**-f**’.
|
||||
|
||||
First List files of the directory.
|
||||
|
||||
$ 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
|
||||
|
||||
and then omit the first file from each set of matches.
|
||||
|
||||
$ 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. Check installed version of fdupes.
|
||||
|
||||
$ fdupes --version
|
||||
|
||||
fdupes 1.51
|
||||
|
||||
11. If you need any help on fdupes you may use switch ‘**-h**’.
|
||||
|
||||
$ 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
|
||||
|
||||
That’s for all now. Let me know how you were finding and deleting duplicates files till now in Linux? and also tell me your opinion about this utility. Put your valuable feedback in the comment section below and don’t forget to like/share us and help us get spread.
|
||||
|
||||
I am working on another utility called **fslint** to remove duplicate files, will soon post and you people will love to read.
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.tecmint.com/fdupes-find-and-delete-duplicate-files-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](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/
|
||||
@ -1,256 +0,0 @@
|
||||
FSSlc translating
|
||||
|
||||
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/
|
||||
117
translated/tech/20150803 Troubleshooting with Linux Logs.md
Normal file
117
translated/tech/20150803 Troubleshooting with Linux Logs.md
Normal file
@ -0,0 +1,117 @@
|
||||
在 Linux 中使用日志来排错
|
||||
================================================================================
|
||||
人们创建日志的主要原因是排错。通常你会诊断为什么问题发生在你的 Linux 系统或应用程序中。错误信息或一些列事件可以给你提供造成根本原因的线索，说明问题是如何发生的，并指出如何解决它。这里有几个使用日志来解决的样例。
|
||||
|
||||
### 登录失败原因 ###
|
||||
|
||||
如果你想检查你的系统是否安全，你可以在验证日志中检查登录失败的和登录成功但可疑的用户。当有人通过不正当或无效的凭据来登录时会出现认证失败，经常使用 SSH 进行远程登录或 su 到本地其他用户来进行访问权。这些是由[插入式验证模块][1]来记录，或 PAM 进行短期记录。在你的日志中会看到像 Failed 这样的字符串密码和未知的用户。成功认证记录包括像 Accepted 这样的字符串密码并打开会话。
|
||||
|
||||
失败的例子:
|
||||
|
||||
pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=10.0.2.2
|
||||
Failed password for invalid user hoover from 10.0.2.2 port 4791 ssh2
|
||||
pam_unix(sshd:auth): check pass; user unknown
|
||||
PAM service(sshd) ignoring max retries; 6 > 3
|
||||
|
||||
成功的例子：
|
||||
|
||||
Accepted password for hoover from 10.0.2.2 port 4792 ssh2
|
||||
pam_unix(sshd:session): session opened for user hoover by (uid=0)
|
||||
pam_unix(sshd:session): session closed for user hoover
|
||||
|
||||
你可以使用 grep 来查找哪些用户失败登录的次数最多。这些都是潜在的攻击者正在尝试和访问失败的账户。这是一个在 ubuntu 系统上的例子。
|
||||
|
||||
$ grep "invalid user" /var/log/auth.log | cut -d ' ' -f 10 | sort | uniq -c | sort -nr
|
||||
23 oracle
|
||||
18 postgres
|
||||
17 nagios
|
||||
10 zabbix
|
||||
6 test
|
||||
|
||||
由于没有标准格式，所以你需要为每个应用程序的日志使用不同的命令。日志管理系统，可以自动分析日志，将它们有效的归类，帮助你提取关键字，如用户名。
|
||||
|
||||
日志管理系统可以使用自动解析功能从 Linux 日志中提取用户名。这使你可以看到用户的信息，并能单个的筛选。在这个例子中，我们可以看到，root 用户登录了 2700 次，因为我们筛选的日志显示尝试登录的只有 root 用户。
|
||||
|
||||
|
||||
|
||||
日志管理系统也让你以时间为做坐标轴的图标来查看使你更容易发现异常。如果有人在几分钟内登录失败一次或两次，它可能是一个真正的用户而忘记了密码。但是，如果有几百个失败的登录并且使用的都是不同的用户名，它更可能是在试图攻击系统。在这里，你可以看到在3月12日，有人试图登录 Nagios 几百次。这显然不是一个合法的系统用户。
|
||||
|
||||
|
||||
|
||||
### 重启的原因 ###
|
||||
|
||||
|
||||
有时候，一台服务器由于系统崩溃或重启而宕机。你怎么知道它何时发生，是谁做的？
|
||||
|
||||
#### 关机命令 ####
|
||||
|
||||
如果有人手动运行 shutdown 命令，你可以看到它的身份在验证日志文件中。在这里，你可以看到，有人从 IP 50.0.134.125 上作为 ubuntu 的用户远程登录了，然后关闭了系统。
|
||||
|
||||
Mar 19 18:36:41 ip-172-31-11-231 sshd[23437]: Accepted publickey for ubuntu from 50.0.134.125 port 52538 ssh
|
||||
Mar 19 18:36:41 ip-172-31-11-231 23437]:sshd[ pam_unix(sshd:session): session opened for user ubuntu by (uid=0)
|
||||
Mar 19 18:37:09 ip-172-31-11-231 sudo: ubuntu : TTY=pts/1 ; PWD=/home/ubuntu ; USER=root ; COMMAND=/sbin/shutdown -r now
|
||||
|
||||
#### 内核初始化 ####
|
||||
|
||||
如果你想看看服务器重新启动的所有原因（包括崩溃），你可以从内核初始化日志中寻找。你需要搜索内核设施和初始化 cpu 的信息。
|
||||
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Initializing cgroup subsys cpuset
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Initializing cgroup subsys cpu
|
||||
Mar 19 18:39:30 ip-172-31-11-231 kernel: [ 0.000000] Linux version 3.8.0-44-generic (buildd@tipua) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #66~precise1-Ubuntu SMP Tue Jul 15 04:01:04 UTC 2014 (Ubuntu 3.8.0-44.66~precise1-generic 3.8.13.25)
|
||||
|
||||
### 检测内存问题 ###
|
||||
|
||||
有很多原因可能导致服务器崩溃，但一个普遍的原因是内存用尽。
|
||||
|
||||
当你系统的内存不足时，进程会被杀死，通常会杀死使用最多资源的进程。当系统正在使用的内存发生错误并且有新的或现有的进程试图使用更多的内存。在你的日志文件查找像 Out of Memory 这样的字符串，内核也会发出杀死进程的警告。这些信息表明系统故意杀死进程或应用程序，而不是允许进程崩溃。
|
||||
|
||||
例如:
|
||||
|
||||
[33238.178288] Out of memory: Kill process 6230 (firefox) score 53 or sacrifice child
|
||||
[29923450.995084] select 5230 (docker), adj 0, size 708, to kill
|
||||
|
||||
你可以使用像 grep 这样的工具找到这些日志。这个例子是在 ubuntu 中:
|
||||
|
||||
$ grep “Out of memory” /var/log/syslog
|
||||
[33238.178288] Out of memory: Kill process 6230 (firefox) score 53 or sacrifice child
|
||||
|
||||
请记住，grep 也要使用内存，所以导致内存不足的错误可能只是运行的 grep。这是另一个分析日志的独特方法！
|
||||
|
||||
### 定时任务错误日志 ###
|
||||
|
||||
cron 守护程序是一个调度器只在指定的日期和时间运行进程。如果进程运行失败或无法完成，那么 cron 的错误出现在你的日志文件中。你可以找到这些文件在 /var/log/cron，/var/log/messages，和 /var/log/syslog 中，具体取决于你的发行版。cron 任务失败原因有很多。通常情况下，问题出在进程中而不是 cron 守护进程本身。
|
||||
|
||||
默认情况下，cron 作业会通过电子邮件发送信息。这里是一个日志中记录的发送电子邮件的内容。不幸的是，你不能看到邮件的内容在这里。
|
||||
|
||||
Mar 13 16:35:01 PSQ110 postfix/pickup[15158]: C3EDC5800B4: uid=1001 from=<hoover>
|
||||
Mar 13 16:35:01 PSQ110 postfix/cleanup[15727]: C3EDC5800B4: message-id=<20150310110501.C3EDC5800B4@PSQ110>
|
||||
Mar 13 16:35:01 PSQ110 postfix/qmgr[15159]: C3EDC5800B4: from=<hoover@loggly.com>, size=607, nrcpt=1 (queue active)
|
||||
Mar 13 16:35:05 PSQ110 postfix/smtp[15729]: C3EDC5800B4: to=<hoover@loggly.com>, relay=gmail-smtp-in.l.google.com[74.125.130.26]:25, delay=4.1, delays=0.26/0/2.2/1.7, dsn=2.0.0, status=sent (250 2.0.0 OK 1425985505 f16si501651pdj.5 - gsmtp)
|
||||
|
||||
你应该想想 cron 在日志中的标准输出以帮助你定位问题。这里展示你可以使用 logger 命令重定向 cron 标准输出到 syslog。用你的脚本来代替 echo 命令，helloCron 可以设置为任何你想要的应用程序的名字。
|
||||
|
||||
*/5 * * * * echo ‘Hello World’ 2>&1 | /usr/bin/logger -t helloCron
|
||||
|
||||
它创建的日志条目：
|
||||
|
||||
Apr 28 22:20:01 ip-172-31-11-231 CRON[15296]: (ubuntu) CMD (echo 'Hello World!' 2>&1 | /usr/bin/logger -t helloCron)
|
||||
Apr 28 22:20:01 ip-172-31-11-231 helloCron: Hello World!
|
||||
|
||||
每个 cron 作业将根据作业的具体类型以及如何输出数据来记录不同的日志。希望在日志中有问题根源的线索，也可以根据需要添加额外的日志记录。
|
||||
|
||||
--------------------------------------------------------------------------------
|
||||
|
||||
via: http://www.loggly.com/ultimate-guide/logging/troubleshooting-with-linux-logs/
|
||||
|
||||
作者：[Jason Skowronski][a1]
|
||||
作者：[Amy Echeverri][a2]
|
||||
作者：[Sadequl Hussain][a3]
|
||||
译者：[strugglingyouth](https://github.com/strugglingyouth)
|
||||
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
|
||||
|
||||
[a1]:https://www.linkedin.com/in/jasonskowronski
|
||||
[a2]:https://www.linkedin.com/in/amyecheverri
|
||||
[a3]:https://www.linkedin.com/pub/sadequl-hussain/14/711/1a7
|
||||
[1]:http://linux.die.net/man/8/pam.d
|
||||
@ -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