document/TranslateProject
2
0
Fork 0
mirror of https://github.com/LCTT/TranslateProject.git synced 2025-01-04 22:00:34 +08:00
Code Issues Packages Projects Releases Wiki Activity

Merge remote-tracking branch 'LCTT/master'

Browse Source
This commit is contained in:
wxy 2018-01-15 22:37:33 +08:00
commit 0930db25a5
22 changed files with 1702 additions and 505 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

0
sources/tech/20190110 Why isn-t open source hot among computer science students.md → 20180110 Why isn-t open source hot among computer science students.md
View File

196
translated/tech/20120611 30 Handy Bash Shell Aliases For Linux - Unix - Mac OS X.md → published/20120611 30 Handy Bash Shell Aliases For Linux - Unix - Mac OS X.md
View File

@ -1,35 +1,43 @@
Linux / Unix / Mac OS X 中的 30 个方便的 Bash shell 别名
30 个方便的 Bash shell 别名
======
bash 别名不是把别的，只不过是指向命令的快捷方式而已。`alias` 命令允许用户只输入一个单词就运行任意一个命令或一组命令(包括命令选项和文件名)。执行 `alias` 命令会显示一个所有已定义别名的列表。你可以在 [~/.bashrc][1] 文件中自定义别名。使用别名可以在命令行中减少输入的时间，使工作更流畅，同时增加生产率。
bash <ruby>别名<rt>alias</rt></ruby>只不过是指向命令的快捷方式而已。`alias` 命令允许用户只输入一个单词就运行任意一个命令或一组命令（包括命令选项和文件名）。执行 `alias` 命令会显示一个所有已定义别名的列表。你可以在 [~/.bashrc][1] 文件中自定义别名。使用别名可以在命令行中减少输入的时间，使工作更流畅，同时增加生产率。
本文通过 30 个 bash shell 别名的实际案例演示了如何创建和使用别名。
![30 Useful Bash Shell Aliase For Linux/Unix Users][2]
## bash alias 的那些事
### bash alias 的那些事
bash shell 中的 alias 命令的语法是这样的：
### 如何列出 bash 别名
```
alias [alias-name[=string]...]
```
#### 如何列出 bash 别名
输入下面的 [alias 命令][3]：
输入下面的 [alias 命令 ][3]：
```
alias
```
结果为：
```
alias ..='cd ..'
alias amazonbackup='s3backup'
alias apt-get='sudo apt-get'
...
```
默认 alias 命令会列出当前用户定义好的别名。
`alias` 命令默认会列出当前用户定义好的别名。
### 如何定义或者说创建一个 bash shell 别名
#### 如何定义或者创建一个 bash shell 别名
使用下面语法 [创建别名][4]：
使用下面语法 [创建别名 ][4]：
```
alias name =value
alias name = 'command'
@ -38,19 +46,22 @@ alias name = '/path/to/script'
alias name = '/path/to/script.pl arg1'
```
举个例子，输入下面命令并回车就会为常用的 `clear`( 清除屏幕)命令创建一个别名 **c**：
举个例子，输入下面命令并回车就会为常用的 `clear`（清除屏幕）命令创建一个别名 `c`：
```
alias c = 'clear'
```
然后输入字母 `c` 而不是 `clear` 后回车就会清除屏幕了：
```
c
```
### 如何临时性地禁用 bash 别名
#### 如何临时性地禁用 bash 别名
下面语法可以[临时性地禁用别名][5]：
下面语法可以[临时性地禁用别名 ][5]：
```
## path/to/full/command
/usr/bin/clear
@ -60,37 +71,43 @@ c
command ls
```
### 如何删除 bash 别名
#### 如何删除 bash 别名
使用 [unalias 命令来删除别名][6]。其语法为：
使用 [unalias 命令来删除别名 ][6]。其语法为：
```
unalias aliasname
unalias foo
```
例如，删除我们之前创建的别名 `c`：
```
unalias c
```
你还需要用文本编辑器删掉 [~/.bashrc 文件 ][1] 中的别名定义(参见下一部分内容)。
你还需要用文本编辑器删掉 [~/.bashrc 文件][1] 中的别名定义（参见下一部分内容）。
### 如何让 bash shell 别名永久生效
#### 如何让 bash shell 别名永久生效
别名 `c` 在当前登录会话中依然有效。但当你登出或重启系统后，别名 `c` 就没有了。为了防止出现这个问题，将别名定义写入 [~/.bashrc file][1] 中，输入：
```
vi ~/.bashrc
```
输入下行内容让别名 `c` 对当前用户永久有效：
```
alias c = 'clear'
```
保存并关闭文件就行了。系统级的别名(也就是对所有用户都生效的别名) 可以放在 `/etc/bashrc` 文件中。请注意，alias 命令内建于各种 shell 中，包括 ksh，tcsh/csh，ash，bash 以及其他 shell。
保存并关闭文件就行了。系统级的别名（也就是对所有用户都生效的别名）可以放在 `/etc/bashrc` 文件中。请注意，`alias` 命令内建于各种 shell 中，包括 ksh，tcsh/csh，ash，bash 以及其他 shell。
### 关于特权权限判断
#### 关于特权权限判断
可以将下面代码加入 `~/.bashrc`：
```
# if user is not root, pass all commands via sudo #
if [ $UID -ne 0 ]; then
@ -99,9 +116,10 @@ if [ $UID -ne 0 ]; then
fi
```
### 定义与操作系统类型相关的别名
#### 定义与操作系统类型相关的别名
可以将下面代码加入 `~/.bashrc` [使用 case 语句][7]：
可以将下面代码加入 `~/.bashrc` [使用 case 语句 ][7]：
```
### Get os name via uname ###
_myos="$(uname)"
@ -115,13 +133,14 @@ case $_myos in
esac
```
## 30 个 bash shell 别名的案例
### 30 个 bash shell 别名的案例
你可以定义各种类型的别名来节省时间并提高生产率。
### #1：控制 ls 命令的输出
#### #1：控制 ls 命令的输出
[ls 命令列出目录中的内容][8] 而你可以对输出进行着色：
[ls 命令列出目录中的内容 ][8] 而你可以对输出进行着色：
```
## Colorize the ls output ##
alias ls = 'ls --color=auto'
@ -133,7 +152,8 @@ alias ll = 'ls -la'
alias l.= 'ls -d . .. .git .gitignore .gitmodules .travis.yml --color=auto'
```
### #2：控制 cd 命令的行为
#### #2：控制 cd 命令的行为
```
## get rid of command not found ##
alias cd..= 'cd ..'
@ -147,9 +167,10 @@ alias .4= 'cd ../../../../'
alias .5= 'cd ../../../../..'
```
### #3：控制 grep 命令的输出
#### #3：控制 grep 命令的输出
[grep 命令是一个用于在纯文本文件中搜索匹配正则表达式的行的命令行工具][9]：
[grep 命令是一个用于在纯文本文件中搜索匹配正则表达式的行的命令行工具 ][9]：
```
## Colorize the grep command output for ease of use (good for log files)##
alias grep = 'grep --color=auto'
@ -157,44 +178,51 @@ alias egrep = 'egrep --color=auto'
alias fgrep = 'fgrep --color=auto'
```
### #4：让计算器默认开启 math 库
#### #4：让计算器默认开启 math 库
```
alias bc = 'bc -l'
```
### #4：生成 sha1 数字签名
#### #4：生成 sha1 数字签名
```
alias sha1 = 'openssl sha1'
```
### #5：自动创建父目录
#### #5：自动创建父目录
[mkdir 命令][10] 用于创建目录：
[mkdir 命令 ][10] 用于创建目录：
```
alias mkdir = 'mkdir -pv'
```
### #6：为 diff 输出着色
#### #6：为 diff 输出着色
你可以[使用 diff 来一行行第比较文件][11] 而一个名为 `colordiff` 的工具可以为 diff 输出着色：
你可以[使用 diff 来一行行第比较文件 ][11] 而一个名为 colordiff 的工具可以为 diff 输出着色：
```
# install colordiff package :)
alias diff = 'colordiff'
```
### #7：让 mount 命令的输出更漂亮，更方便人类阅读
#### #7：让 mount 命令的输出更漂亮，更方便人类阅读
```
alias mount = 'mount |column -t'
```
### #8：简化命令以节省时间
#### #8：简化命令以节省时间
```
# handy short cuts #
alias h = 'history'
alias j = 'jobs -l'
```
### #9：创建一系列新命令
#### #9：创建一系列新命令
```
alias path = 'echo -e ${PATH//:/\\n}'
alias now = 'date +"%T"'
@ -202,7 +230,8 @@ alias nowtime =now
alias nowdate = 'date +"%d-%m-%Y"'
```
### #10：设置 vim 为默认编辑器
#### #10：设置 vim 为默认编辑器
```
alias vi = vim
alias svi = 'sudo vi'
@ -210,7 +239,8 @@ alias vis = 'vim "+set si"'
alias edit = 'vim'
```
### #11：控制网络工具 ping 的输出
#### #11：控制网络工具 ping 的输出
```
# Stop after sending count ECHO_REQUEST packets #
alias ping = 'ping -c 5'
@ -219,16 +249,18 @@ alias ping = 'ping -c 5'
alias fastping = 'ping -c 100 -s.2'
```
### #12：显示打开的端口
#### #12：显示打开的端口
使用 [netstat 命令][12] 可以快速列出服务区中所有的 TCP/UDP 端口：
使用 [netstat 命令 ][12] 可以快速列出服务区中所有的 TCP/UDP 端口：
```
alias ports = 'netstat -tulanp'
```
### #13：唤醒休眠额服务器
#### #13：唤醒休眠的服务器
[Wake-on-LAN (WOL) 是一个以太网标准][13]，可以通过网络消息来开启服务器。你可以使用下面别名来[快速激活 nas 设备][14] 以及服务器：
[Wake-on-LAN (WOL) 是一个以太网标准 ][13]，可以通过网络消息来开启服务器。你可以使用下面别名来[快速激活 nas 设备 ][14] 以及服务器：
```
## replace mac with your actual server mac address #
alias wakeupnas01 = '/usr/bin/wakeonlan 00:11:32:11:15:FC'
@ -236,9 +268,10 @@ alias wakeupnas02 = '/usr/bin/wakeonlan 00:11:32:11:15:FD'
alias wakeupnas03 = '/usr/bin/wakeonlan 00:11:32:11:15:FE'
```
### #14：控制防火墙 (iptables) 的输出
#### #14：控制防火墙 (iptables) 的输出
[Netfilter 是一款 Linux 操作系统上的主机防火墙][15]。它是 Linux 发行版中的一部分，且默认情况下是激活状态。[这里列出了大多数 Liux 新手防护入侵者最常用的 iptables 方法][16]。
[Netfilter 是一款 Linux 操作系统上的主机防火墙 ][15]。它是 Linux 发行版中的一部分，且默认情况下是激活状态。[这里列出了大多数 Liux 新手防护入侵者最常用的 iptables 方法 ][16]。
```
## shortcut for iptables and pass it via sudo#
alias ipt = 'sudo /sbin/iptables'
@ -251,7 +284,8 @@ alias iptlistfw = 'sudo /sbin/iptables -L FORWARD -n -v --line-numbers'
alias firewall =iptlist
```
### #15：使用 curl 调试 web 服务器 /cdn 上的问题
#### #15：使用 curl 调试 web 服务器 / CDN 上的问题
```
# get web server headers #
alias header = 'curl -I'
@ -260,7 +294,8 @@ alias header = 'curl -I'
alias headerc = 'curl -I --compress'
```
### #16：增加安全性
#### #16：增加安全性
```
# do not delete / or prompt if deleting more than 3 files at a time #
alias rm = 'rm -I --preserve-root'
@ -276,9 +311,10 @@ alias chmod = 'chmod --preserve-root'
alias chgrp = 'chgrp --preserve-root'
```
### #17：更新 Debian Linux 服务器
#### #17：更新 Debian Linux 服务器
[apt-get 命令][17] 用于通过因特网安装软件包 (ftp 或 http)。你也可以一次性升级所有软件包：
[apt-get 命令 ][17] 用于通过因特网安装软件包 (ftp 或 http)。你也可以一次性升级所有软件包：
```
# distro specific - Debian / Ubuntu and friends #
# install with apt-get
@ -289,25 +325,27 @@ alias updatey = "sudo apt-get --yes"
alias update = 'sudo apt-get update && sudo apt-get upgrade'
```
### #18：更新 RHEL / CentOS / Fedora Linux 服务器
#### #18：更新 RHEL / CentOS / Fedora Linux 服务器
[yum 命令][18] 是 RHEL / CentOS / Fedora Linux 以及其他基于这些发行版的 Linux 上的软件包管理工具：
[yum 命令 ][18] 是 RHEL / CentOS / Fedora Linux 以及其他基于这些发行版的 Linux 上的软件包管理工具：
```
## distrp specifc RHEL/CentOS ##
alias update = 'yum update'
alias updatey = 'yum -y update'
```
### #19：优化 sudo 和 su 命令
#### #19：优化 sudo 和 su 命令
```
# become root #
alias root = 'sudo -i'
alias su = 'sudo -i'
```
### #20：使用 sudo 执行 halt/reboot 命令
#### #20：使用 sudo 执行 halt/reboot 命令
[shutdown 命令 ][19] 会让 Linux / Unix 系统关机：
[shutdown 命令][19] 会让 Linux / Unix 系统关机：
```
# reboot / halt / poweroff
alias reboot = 'sudo /sbin/reboot'
@ -316,7 +354,8 @@ alias halt = 'sudo /sbin/halt'
alias shutdown = 'sudo /sbin/shutdown'
```
### #21：控制 web 服务器
#### #21：控制 web 服务器
```
# also pass it via sudo so whoever is admin can reload it without calling you #
alias nginxreload = 'sudo /usr/local/nginx/sbin/nginx -s reload'
@ -327,7 +366,8 @@ alias httpdreload = 'sudo /usr/sbin/apachectl -k graceful'
alias httpdtest = 'sudo /usr/sbin/apachectl -t && /usr/sbin/apachectl -t -D DUMP_VHOSTS'
```
### #22：与备份相关的别名
#### #22：与备份相关的别名
```
# if cron fails or if you want backup on demand just run these commands #
# again pass it via sudo so whoever is in admin group can start the job #
@ -342,7 +382,8 @@ alias rsnapshotmonthly = 'sudo /home/scripts/admin/scripts/backup/wrapper.rsnaps
alias amazonbackup =s3backup
```
### #23：桌面应用相关的别名 - 按需播放的 avi/mp3 文件
#### #23：桌面应用相关的别名 - 按需播放的 avi/mp3 文件
```
## play video files in a current directory ##
# cd ~/Download/movie-name
@ -364,10 +405,10 @@ alias nplaymp3 = 'for i in /nas/multimedia/mp3/*.mp3; do mplayer "$i"; done'
alias music = 'mplayer --shuffle *'
```
#### #24：设置系统管理相关命令的默认网卡
### #24：设置系统管理相关命令的默认网卡
[vnstat 一款基于终端的网络流量检测器][20]。[dnstop 是一款分析 DNS 流量的终端工具][21]。[tcptrack 和 iftop 命令显示][22] TCP/UDP 连接方面的信息，它监控网卡并显示其消耗的带宽。
[vnstat 一款基于终端的网络流量检测器 ][20]。[dnstop 是一款分析 DNS 流量的终端工具 ][21]。[tcptrack 和 iftop 命令显示 ][22] TCP/UDP 连接方面的信息，它监控网卡并显示其消耗的带宽。
```
## All of our servers eth1 is connected to the Internets via vlan / router etc ##
alias dnstop = 'dnstop -l 5 eth1'
@ -381,7 +422,8 @@ alias ethtool = 'ethtool eth1'
alias iwconfig = 'iwconfig wlan0'
```
### #25：快速获取系统内存，cpu 使用，和 gpu 内存相关信息
#### #25：快速获取系统内存，cpu 使用，和 gpu 内存相关信息
```
## pass options to free ##
alias meminfo = 'free -m -l -t'
@ -404,9 +446,10 @@ alias cpuinfo = 'lscpu'
alias gpumeminfo = 'grep -i --color memory /var/log/Xorg.0.log'
```
### #26：控制家用路由器
#### #26：控制家用路由器
`curl` 命令可以用来 [重启 Linksys 路由器][23]。
curl 命令可以用来 [重启 Linksys 路由器 ][23]。
```
# Reboot my home Linksys WAG160N / WAG54 / WAG320 / WAG120N Router / Gateway from *nix.
alias rebootlinksys = "curl -u 'admin:my-super-password' 'http://192.168.1.2/setup.cgi?todo=reboot'"
@ -415,15 +458,17 @@ alias rebootlinksys = "curl -u 'admin:my-super-password' 'http://192.168.1.2/set
alias reboottomato = "ssh admin@192.168.1.1 /sbin/reboot"
```
### #27 wget 默认断点续传
#### #27 wget 默认断点续传
[GNU wget 是一款用来从 web 下载文件的自由软件][25]。它支持 HTTP，HTTPS，以及 FTP 协议，而且它也支持断点续传：
[GNU Wget 是一款用来从 web 下载文件的自由软件 ][25]。它支持 HTTP，HTTPS，以及 FTP 协议，而且它页支持断点续传：
```
## this one saved by butt so many times ##
alias wget = 'wget -c'
```
### #28 使用不同浏览器来测试网站
#### #28 使用不同浏览器来测试网站
```
## this one saved by butt so many times ##
alias ff4 = '/opt/firefox4/firefox'
@ -438,9 +483,10 @@ alias ff =ff13
alias browser =chrome
```
### #29：关于 ssh 别名的注意事项
#### #29：关于 ssh 别名的注意事项
不要创建 ssh 别名，代之以 `~/.ssh/config` 这个 OpenSSH SSH 客户端配置文件。它的选项更加丰富。下面是一个例子：
```
Host server10
Hostname 1.2.3.4
@ -451,12 +497,13 @@ Host server10
TCPKeepAlive yes
```
然后你就可以使用下面语句连接 peer1 了：
然后你就可以使用下面语句连接 server10 了：
```
$ ssh server10
```
### #30：现在该分享你的别名了
#### #30：现在该分享你的别名了
```
## set some other defaults ##
@ -486,27 +533,26 @@ alias cdnmdel = '/home/scripts/admin/cdn/purge_cdn_cache --profile akamai --stdi
alias amzcdnmdel = '/home/scripts/admin/cdn/purge_cdn_cache --profile amazon --stdin'
```
## 结论
### 总结
本文总结了 *nix bash 别名的多种用法：
1。为命令设置默认的参数(例如通过 `alias ethtool='ethtool eth0'` 设置 ethtool 命令的默认参数为 eth0)。
2。修正错误的拼写(通过 `alias cd。.='cd .。'`让 `cd。.` 变成 `cd .。`)。
3。缩减输入。
4。设置系统中多版本命令的默认路径(例如 GNU/grep 位于 /usr/local/bin/grep 中而 Unix grep 位于 /bin/grep 中。若想默认使用 GNU grep 则设置别名 `grep='/usr/local/bin/grep'` )。
5。通过默认开启命令(例如 rm，mv 等其他命令)的交互参数来增加 Unix 的安全性。
6。为老旧的操作系统(比如 MS-DOS 或者其他类似 Unix 的操作系统)创建命令以增加兼容性(比如 `alias del=rm` )。
1. 为命令设置默认的参数（例如通过 `alias ethtool='ethtool eth0'` 设置 ethtool 命令的默认参数为 eth0）。
2. 修正错误的拼写（通过 `alias cd..='cd ..'`让 `cd..` 变成 `cd ..`）。
3. 缩减输入。
4. 设置系统中多版本命令的默认路径（例如 GNU/grep 位于 `/usr/local/bin/grep` 中而 Unix grep 位于 `/bin/grep` 中。若想默认使用 GNU grep 则设置别名 `grep='/usr/local/bin/grep'` )。
5. 通过默认开启命令（例如 `rm`，`mv` 等其他命令）的交互参数来增加 Unix 的安全性。
6. 为老旧的操作系统（比如 MS-DOS 或者其他类似 Unix 的操作系统）创建命令以增加兼容性（比如 `alias del=rm`）。
我已经分享了多年来为了减少重复输入命令而使用的别名。若你知道或使用的哪些 bash/ksh/csh 别名能够减少输入，请在留言框中分享。
--------------------------------------------------------------------------------
via: https://www.cyberciti.biz/tips/bash-aliases-mac-centos-linux-unix.html
作者：[nixCraft][a]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

32
translated/tech/20170918 Linux fmt command - usage and examples.md → published/20170918 Linux fmt command - usage and examples.md
View File

@ -1,13 +1,13 @@
Linux fmt 命令 - 用法与案例
Linux 的 fmt 命令用法与案例
======
有时你会发现需要格式化某个文本文件中的内容。比如，该文本文件每行一个单词，而人物是把所有的单词都放在同一行。当然，你可以手工来做，但没人喜欢手工做这么耗时的工作。而且，这只是一个例子 - 事实上的任务可能千奇百怪。
有时你会发现需要格式化某个文本文件中的内容。比如，该文本文件每行一个单词，而任务是把所有的单词都放在同一行。当然，你可以手工来做，但没人喜欢手工做这么耗时的工作。而且，这只是一个例子 - 事实上的任务可能千奇百怪。
好在，有一个命令可以满足至少一部分的文本格式化的需求。这个工具就是 `fmt`。本教程将会讨论 `fmt` 的基本用法以及它提供的一些主要功能。文中所有的命令和指令都在 Ubuntu 16.04LTS 下经过了测试。
### Linux fmt 命令
fmt 命令是一个简单的文本格式化工具，任何人都能在命令行下运行它。它的基本语法为：
`fmt` 命令是一个简单的文本格式化工具，任何人都能在命令行下运行它。它的基本语法为：
```
fmt [-WIDTH] [OPTION]... [FILE]...
@ -15,15 +15,13 @@ fmt [-WIDTH] [OPTION]... [FILE]...
它的 man 页是这么说的：
```
重新格式化文件FILE(s)中的每一个段落,将结果写到标准输出. 选项 -WIDTH 是 --width=DIGITS 形式的缩写
```
> 重新格式化文件中的每一个段落，将结果写到标准输出。选项 `-WIDTH` 是 `--width=DIGITS` 形式的缩写。
下面这些问答方式的例子应该能让你对 fmt 的用法有很好的了解。
下面这些问答方式的例子应该能让你对 `fmt` 的用法有很好的了解。
### Q1。如何使用 fmt 来将文本内容格式成同一行？
### Q1、如何使用 fmt 来将文本内容格式成同一行？
使用 `fmt` 命令的基本格式（省略任何选项）就能做到这一点。你只需要将文件名作为参数传递给它。
使用 `fmt` 命令的基本形式（省略任何选项）就能做到这一点。你只需要将文件名作为参数传递给它。
```
fmt [file-name]
@ -33,9 +31,9 @@ fmt [file-name]
[![format contents of file in single line][1]][2]
你可以看到文件中多行内容都被格式化成同一行了。请注意，这并不会修改原文件（也就是 file1）。
你可以看到文件中多行内容都被格式化成同一行了。请注意，这并不会修改原文件（file1）。
### Q2。如何修改最大行宽？
### Q2、如何修改最大行宽？
默认情况下，`fmt` 命令产生的输出中的最大行宽为 75。然而，如果你想的话，可以用 `-w` 选项进行修改，它接受一个表示新行宽的数字作为参数值。
@ -47,7 +45,7 @@ fmt -w [n] [file-name]
[![change maximum line width][3]][4]
### Q3。如何让 fmt 突出显示第一行？
### Q3、如何让 fmt 突出显示第一行？
这是通过让第一行的缩进与众不同来实现的，你可以使用 `-t` 选项来实现。
@ -57,7 +55,7 @@ fmt -t [file-name]
[![make fmt highlight the first line][5]][6]
### Q4。如何使用 fmt 拆分长行？
### Q4、如何使用 fmt 拆分长行？
fmt 命令也能用来对长行进行拆分，你可以使用 `-s` 选项来应用该功能。
@ -69,9 +67,9 @@ fmt -s [file-name]
[![make fmt split long lines][7]][8]
### Q5。如何在单词与单词之间，行与行之间用空格分开？
### Q5、如何在单词与单词之间，句子之间用空格分开？
fmt 命令提供了一个 `-u` 选项，这会在单词与单词之间用单个空格分开，行与行之间用两个空格分开。你可以这样用：
fmt 命令提供了一个 `-u` 选项，这会在单词与单词之间用单个空格分开，句子之间用两个空格分开。你可以这样用：
```
fmt -u [file-name]
@ -81,7 +79,7 @@ fmt -u [file-name]
### 总结
没错，fmt 提供的功能不多，但不代表它的应用就不广泛。因为你永远不知道什么时候会用到它。在本教程中，我们已经讲解了 `fmt` 提供的主要选项。若想了解更多细节，请查看该工具的 [man 页 ][9]。
没错，`fmt` 提供的功能不多，但不代表它的应用就不广泛。因为你永远不知道什么时候会用到它。在本教程中，我们已经讲解了 `fmt` 提供的主要选项。若想了解更多细节，请查看该工具的 [man 页][9]。
--------------------------------------------------------------------------------
@ -90,7 +88,7 @@ via: https://www.howtoforge.com/linux-fmt-command/
作者：[Himanshu Arora][a]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

23
translated/tech/20170919 What Are Bitcoins.md → published/20170919 What Are Bitcoins.md
View File

@ -3,37 +3,38 @@
![what are bitcoins](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/what-are-bitcoins_orig.jpg)
**[比特币][1]** 是一种数字货币或者说是电子现金，依靠点对点技术来完成交易。 由于使用点对点技术作为主要网络，比特币提供了一个类似于管理型经济的社区。 这就是说，比特币消除了货币管理的集中式管理方式，促进了货币的社区管理。 大部分比特币数字现金的挖掘和管理软件也是开源的。
<ruby>[比特币][1]<rt>Bitcoin</rt></ruby> 是一种数字货币或者说是电子现金，依靠点对点技术来完成交易。 由于使用点对点技术作为主要网络，比特币提供了一个类似于<ruby>管制经济<rt>managed economy</rt></ruby>的社区。 这就是说，比特币消除了货币管理的集中式管理方式，促进了货币的社区管理。 大部分比特币数字现金的挖掘和管理软件也是开源的。
第一个比特币软件是由Satoshi Nakamoto开发的，基于开源的密码协议。 比特币最小单位被称为Satoshi，它基本上是单比特币（0.00000001 BTC）的百万分之一。
第一个比特币软件是由<ruby>中本聪<rt>Satoshi Nakamoto</rt></ruby>开发的，基于开源的密码协议。 比特币最小单位被称为<ruby>聪<rt>Satoshi</rt></ruby>，它基本上是一个比特币的百万分之一（0.00000001 BTC）。
人们不能低估BITCOINS在数字经济中消除的界限。 例如，BITCOIN消除了由中央机构对货币进行的管理控制，并向整个社区提供控制和管理。 此外，BITCOIN基于开放源代码密码协议的事实使其成为一个开放的领域，其中存在价值波动，通货紧缩和通货膨胀等严格的活动。 当许多互联网用户正在意识到他们在网上完成交易的隐私性时，但是比特币正在变得比以往更受欢迎。 但是，对于那些了解暗网及其工作原理的人们，可以确认有些人早就开始使用它了。
人们不能低估比特币在数字经济中消除的界限。 例如，比特币消除了由中央机构对货币进行的管理控制，并将控制和管理提供给整个社区。 此外，比特币基于开放源代码密码协议的事实使其成为一个开放的领域，其中存在价值波动、通货紧缩和通货膨胀等严格的活动。 当许多互联网用户正在意识到他们在网上完成交易的隐私性时，比特币正在变得比以往更受欢迎。 但是，对于那些了解暗网及其工作原理的人们，可以确认有些人早就开始使用它了。
不利的一面是，比特币在匿名支付方面也非常安全，可能会对安全或个人健康构成威胁。 例如，暗网市场是进口药物甚至武器的主要供应商和零售商。 在暗网中使用BITCOINs有助于这种犯罪活动。 尽管如此，如果使用得当，比特币有许多的好处，可以消除一些由于集中的货币代理管理导致的经济上的谬误。 另外，比特币允许在世界任何地方交换现金。 比特币的使用也可以减少假冒，印刷或贬值。 同时，依托对等网络作为骨干网络，促进交易记录的分布式权限，交易会更加安全。
不利的一面是，比特币在匿名支付方面也非常安全，可能会对安全或个人健康构成威胁。 例如，暗网市场是进口药物甚至武器的主要供应商和零售商。 在暗网中使用比特币有助于这种犯罪活动。 尽管如此，如果使用得当，比特币有许多的好处，可以消除一些由于集中的货币代理管理导致的经济上的谬误。 另外，比特币允许在世界任何地方交换现金。 比特币的使用也可以减少货币假冒、印刷或贬值。 同时，依托对等网络作为骨干网络，促进交易记录的分布式权限，交易会更加安全。
比特币的其他优点包括：
- 在网上商业世界里，比特币促进资金安全和完全控制。这是因为买家受到保护，以免商家可能想要为较低成本的服务额外收取钱财。买家也可以选择在交易后不分享个人信息。此外，由于隐藏了个人信息，也就保护了身份不被盗窃。
- 对于主要的共同货币灾难，比如如丢失，冻结或损坏，比特币是一种替代品。但是，始终都建议对比特币进行备份并使用密码加密。
- 对于主要的常见货币灾难，比如如丢失、冻结或损坏，比特币是一种替代品。但是，始终都建议对比特币进行备份并使用密码加密。
- 使用比特币进行网上购物和付款时，收取的费用少或者不收取。这就提高了使用时的可承受性。
- 与其他电子货币不同，商家也面临较少的欺诈风险，因为比特币交易是无法逆转的。即使在高犯罪率和高欺诈的时刻，比特币也是有用的，因为在公开的公共总账（区块链）上难以对付某个人。
- 比特币货币也很难被操纵，因为它是开源的，密码协议是非常安全的。
- 交易也可以随时随地进行验证和批准。这是数字货币提供的灵活性水准。
还可以阅读 - [Bitkey：专用于比特币交易的Linux发行版][2]
还可以阅读 - [Bitkey：专用于比特币交易的 Linux 发行版][2]
### 如何挖掘比特币和完成必要的比特币管理任务的应用程序
在数字货币中，BITCOIN挖矿和管理需要额外的软件。有许多开源的比特币管理软件，便于进行支付，接收付款，加密和备份比特币，还有很多的比特币挖掘软件。有些网站，比如：通过查看广告赚取免费比特币的[Freebitcoin][4]，MoonBitcoin是另一个可以免费注册并获得比特币的网站。但是，如果有空闲时间和相当多的人脉圈参与，会很方便。有很多提供比特币挖矿的网站，可以轻松注册然后开始挖矿。其中一个主要秘诀就是尽可能引入更多的人构建成一个大型的网络。
在数字货币中，比特币挖矿和管理需要额外的软件。有许多开源的比特币管理软件，便于进行支付，接收付款，加密和备份比特币，还有很多的比特币挖掘软件。有些网站，比如：通过查看广告赚取免费比特币的 [Freebitcoin][4]，MoonBitcoin 是另一个可以免费注册并获得比特币的网站。但是，如果有空闲时间和相当多的人脉圈参与，会很方便。有很多提供比特币挖矿的网站，可以轻松注册然后开始挖矿。其中一个主要秘诀就是尽可能引入更多的人构建成一个大型的网络。
与比特币一起使用时需要的应用程序包括比特币钱包，使得人们可以安全的持有比特币。这就像使用实物钱包来保存硬通货币一样，而这里是以数字形式存在d的。钱包可以在这里下载 - [比特币-钱包][6]。其他类似的应用包括：与比特币钱包类似的[区块链][7]。
与比特币一起使用时需要的应用程序包括比特币钱包，使得人们可以安全的持有比特币。这就像使用实物钱包来保存硬通货币一样，而这里是以数字形式存在的。钱包可以在这里下载 —— [比特币-钱包][6]。其他类似的应用包括：与比特币钱包类似的[区块链][7]。
下面的屏幕截图分别显示了Freebitco和MoonBitco这两个挖矿网站。
下面的屏幕截图分别显示了 Freebitco 和 MoonBitco 这两个挖矿网站。
[![freebitco bitcoin mining site](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/freebitco-bitcoin-mining-site_orig.jpg)][8]
[![moonbitcoin bitcoin mining site](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/moonbitcoin-bitcoin-mining-site_orig.png)][9]
获得比特币的方式多种多样。其中一些包括比特币挖矿机的使用，比特币在交易市场的购买以及免费的比特币在线采矿。比特币可以在[MtGox][10]，[bitNZ][11]，[Bitstamp][12]，[BTC-E][13]，[VertEx][14]等等这些网站买到，这些网站都提供了开源开源应用程序。这些应用包括：Bitminter，[5OMiner][15]，[BFG Miner][16]等等。这些应用程序使用一些图形卡和处理器功能来生成比特币。在个人电脑上开采比特币的效率在很大程度上取决于显卡的类型和采矿设备的处理器。此外，还有很多安全的在线存储用于备份比特币。这些网站免费提供比特币存储服务。比特币管理网站的例子包括：[xapo][17] , [BlockChain][18] 等。在这些网站上注册需要有效的电子邮件和电话号码进行验证。 Xapo通过电话应用程序提供额外的安全性，无论何时进行新的登录都需要做请求验证。
获得比特币的方式多种多样。其中一些包括比特币挖矿机的使用，比特币在交易市场的购买以及免费的比特币在线采矿。比特币可以在 [MtGox][10]（LCTT 译注：本文比较陈旧，此交易所已经倒闭），[bitNZ][11]，[Bitstamp][12]，[BTC-E][13]，[VertEx][14] 等等这些网站买到，这些网站都提供了开源开源应用程序。这些应用包括：Bitminter、[5OMiner][15]，[BFG Miner][16] 等等。这些应用程序使用一些图形卡和处理器功能来生成比特币。在个人电脑上开采比特币的效率在很大程度上取决于显卡的类型和采矿设备的处理器。（LCTT 译注：目前个人挖矿已经几乎毫无意义了）此外，还有很多安全的在线存储用于备份比特币。这些网站免费提供比特币存储服务。比特币管理网站的例子包括：[xapo][17] , [BlockChain][18] 等。在这些网站上注册需要有效的电子邮件和电话号码进行验证。 Xapo 通过电话应用程序提供额外的安全性，无论何时进行新的登录都需要做请求验证。
### 比特币的缺点
@ -49,7 +50,7 @@ via: http://www.linuxandubuntu.com/home/things-you-need-to-know-about-bitcoins
作者：[LINUXANDUBUNTU][a]
译者：[Flowsnow](https://github.com/Flowsnow)
校对：[校对者ID](https://github.com/校对者ID)
校对：[wxy](https://github.com/wxy)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

1
sources/talk/20180111 AI and machine learning bias has dangerous implications.md
View File

@ -1,5 +1,6 @@
AI and machine learning bias has dangerous implications
======
translating
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/LAW_goodbadugly.png?itok=ZxaimUWU)

383
sources/tech/20100419 10 Tools To Add Some Spice To Your UNIX-Linux Shell Scripts.md Normal file
View File

@ -0,0 +1,383 @@
10 Tools To Add Some Spice To Your UNIX/Linux Shell Scripts
======
There are some misconceptions that shell scripts are only for a CLI environment. You can efficiently use various tools to write GUI and network (socket) scripts under KDE or Gnome desktops. Shell scripts can make use of some of the GUI widget (menus, warning boxes, progress bars, etc.). You can always control the final output, cursor position on the screen, various output effects, and more. With the following tools, you can build powerful, interactive, user-friendly UNIX / Linux bash shell scripts.
Creating GUI application is not an expensive task but a task that takes time and patience. Luckily, both UNIX and Linux ships with plenty of tools to write beautiful GUI scripts. The following tools are tested on FreeBSD and Linux operating systems but should work under other UNIX like operating systems.
### 1. notify-send Command
The notify-send command allows you to send desktop notifications to the user via a notification daemon from the command line. This is useful to inform the desktop user about an event or display some form of information without getting in the user's way. You need to install the following package on a Debian/Ubuntu Linux using [apt command][1]/[apt-get command][2]:
`$ sudo apt-get install libnotify-bin`
CentOS/RHEL user try the following [yum command][3]:
`$ sudo yum install libnotify`
Fedora Linux user type the following dnf command:
`$ sudo dnf install libnotify`
In this example, send simple desktop notification from the command line, enter:
```
### send some notification ##
notify-send "rsnapshot done :)"
```
Sample outputs:
![Fig:01: notify-send in action ][4]
Here is another code with additional options:
```
....
alert=18000
live=$(lynx --dump http://money.rediff.com/ | grep 'BSE LIVE' | awk '{ print $5}' | sed 's/,//g;s/\.[0-9]*//g')
[ $notify_counter -eq 0 ] && [ $live -ge $alert ] && { notify-send -t 5000 -u low -i "BSE Sensex touched 18k"; notify_counter=1; }
...
```
Sample outputs:
![Fig.02: notify-send with timeouts and other options][5]
Where,
* -t 5000: Specifies the timeout in milliseconds ( 5000 milliseconds = 5 seconds)
* -u low : Set the urgency level (i.e. low, normal, or critical).
* -i gtk-dialog-info : Set an icon filename or stock icon to display (you can set path as -i /path/to/your-icon.png).
For more information on use of the notify-send utility, please refer to the notify-send man page, viewable by typing man notify-send from the command line:
```
man notify-send
```
### #2: tput Command
The tput command is used to set terminal features. With tput you can set:
* Move the cursor around the screen.
* Get information about terminal.
* Set colors (background and foreground).
* Set bold mode.
* Set reverse mode and much more.
Here is a sample code:
```
#!/bin/bash
# clear the screen
tput clear
# Move cursor to screen location X,Y (top left is 0,0)
tput cup 3 15
# Set a foreground colour using ANSI escape
tput setaf 3
echo "XYX Corp LTD."
tput sgr0
tput cup 5 17
# Set reverse video mode
tput rev
echo "M A I N - M E N U"
tput sgr0
tput cup 7 15
echo "1. User Management"
tput cup 8 15
echo "2. Service Management"
tput cup 9 15
echo "3. Process Management"
tput cup 10 15
echo "4. Backup"
# Set bold mode
tput bold
tput cup 12 15
read -p "Enter your choice [1-4] " choice
tput clear
tput sgr0
tput rc
```
Sample outputs:
![Fig.03: tput in action][6]
For more detail concerning the tput command, see the following man page:
```
man 5 terminfo
man tput
```
### #3: setleds Command
The setleds command allows you to set the keyboard leds. In this example, set NumLock on:
```
setleds -D +num
```
To turn it off NumLock, enter:
```
setleds -D -num
```
* -caps : Clear CapsLock.
* +caps : Set CapsLock.
* -scroll : Clear ScrollLock.
* +scroll : Set ScrollLock.
See setleds command man page for more information and options:
`man setleds`
### #4: zenity Command
The [zenity commadn will display GTK+ dialogs box][7], and return the users input. This allows you to present information, and ask for information from the user, from all manner of shell scripts. Here is a sample GUI client for the whois directory service for given domain name:
```shell
#!/bin/bash
# Get domain name
_zenity="/usr/bin/zenity"
_out="/tmp/whois.output.$$"
domain=$(${_zenity} --title "Enter domain" \
--entry --text "Enter the domain you would like to see whois info" )
if [ $? -eq 0 ]
then
# Display a progress dialog while searching whois database
whois $domain | tee >(${_zenity} --width=200 --height=100 \
--title="whois" --progress \
--pulsate --text="Searching domain info..." \
--auto-kill --auto-close \
--percentage=10) >${_out}
# Display back output
${_zenity} --width=800 --height=600 \
--title "Whois info for $domain" \
--text-info --filename="${_out}"
else
${_zenity} --error \
--text="No input provided"
fi
```
Sample outputs:
![Fig.04: zenity in Action][8]
See the zenity man page for more information and all other supports GTK+ widgets:
```
zenity --help
man zenity
```
### #5: kdialog Command
kdialog is just like zenity but it is designed for KDE desktop / qt apps. You can display dialogs using kdialog. The following will display message on screen:
```
kdialog --dontagain myscript:nofilemsg --msgbox "File: '~/.backup/config' not found."
```
Sample outputs:
![Fig.05: Suppressing the display of a dialog ][9]
See [shell scripting with KDE Dialogs][10] tutorial for more information.
### #6: Dialog
[Dialog is an application used in shell scripts][11] which displays text user interface widgets. It uses the curses or ncurses library. Here is a sample code:
```
#!/bin/bash
dialog --title "Delete file" \
--backtitle "Linux Shell Script Tutorial Example" \
--yesno "Are you sure you want to permanently delete \"/tmp/foo.txt\"?" 7 60
# Get exit status
# 0 means user hit [yes] button.
# 1 means user hit [no] button.
# 255 means user hit [Esc] key.
response=$?
case $response in
0) echo "File deleted.";;
1) echo "File not deleted.";;
255) echo "[ESC] key pressed.";;
esac
```
See the dialog man page for details:
`man dialog`
#### A Note About Other User Interface Widgets Tools
UNIX and Linux comes with lots of other tools to display and control apps from the command line, and shell scripts can make use of some of the KDE / Gnome / X widget set:
* **gmessage** - a GTK-based xmessage clone.
* **xmessage** - display a message or query in a window (X-based /bin/echo)
* **whiptail** - display dialog boxes from shell scripts
* **python-dialog** - Python module for making simple Text/Console-mode user interfaces
### #7: logger command
The logger command writes entries in the system log file such as /var/log/messages. It provides a shell command interface to the syslog system log module:
```
logger "MySQL database backup failed."
tail -f /var/log/messages
logger -t mysqld -p daemon.error "Database Server failed"
tail -f /var/log/syslog
```
Sample outputs:
```
Apr 20 00:11:45 vivek-desktop kernel: [38600.515354] CPU0: Temperature/speed normal
Apr 20 00:12:20 vivek-desktop mysqld: Database Server failed
```
See howto [write message to a syslog / log file][12] for more information. Alternatively, you can see the logger man page for details:
`man logger`
### #8: setterm Command
The setterm command can set various terminal attributes. In this example, force screen to turn black in 15 minutes. Monitor standby will occur at 60 minutes:
```
setterm -blank 15 -powersave powerdown -powerdown 60
```
In this example show underlined text for xterm window:
```
setterm -underline on;
echo "Add Your Important Message Here"
setterm -underline off
```
Another useful option is to turn on or off cursor:
```
setterm -cursor off
```
Turn it on:
```
setterm -cursor on
```
See the setterm command man page for details:
`man setterm`
### #9: smbclient: Sending Messages To MS-Windows Workstations
The smbclient command can talk to an SMB/CIFS server. It can send a message to selected users or all users on MS-Windows systems:
```
smbclient -M WinXPPro <<eof
Message 1
Message 2
...
..
EOF
```
OR
```
echo "${Message}" | smbclient -M salesguy2
```
See smbclient man page or read our previous post about "[sending a message to Windows Workstation"][13] with smbclient command:
`man smbclient`
### #10: Bash Socket Programming
Under bash you can open a socket to pass some data through it. You don't have to use curl or lynx commands to just grab data from remote server. Bash comes with two special device files which can be used to open network sockets. From the bash man page:
1. **/dev/tcp/host/port** - If host is a valid hostname or Internet address, and port is an integer port number or service name, bash attempts to open a TCP connection to the corresponding socket.
2. **/dev/udp/host/port** - If host is a valid hostname or Internet address, and port is an integer port number or service name, bash attempts to open a UDP connection to the corresponding socket.
You can use this technquie to dermine if port is open or closed on local or remote server without using nmap or other port scanner:
```
# find out if TCP port 25 open or not
(echo >/dev/tcp/localhost/25) &>/dev/null && echo "TCP port 25 open" || echo "TCP port 25 close"
```
You can use [bash loop and find out open ports][14] with the snippets:
```
echo "Scanning TCP ports..."
for p in {1..1023}
do
(echo >/dev/tcp/localhost/$p) >/dev/null 2>&1 && echo "$p open"
done
```
Sample outputs:
```
Scanning TCP ports...
22 open
53 open
80 open
139 open
445 open
631 open
```
In this example, your bash script act as an HTTP client:
```
#!/bin/bash
exec 3<> /dev/tcp/${1:-www.cyberciti.biz}/80
printf "GET / HTTP/1.0\r\n" >&3
printf "Accept: text/html, text/plain\r\n" >&3
printf "Accept-Language: en\r\n" >&3
printf "User-Agent: nixCraft_BashScript v.%s\r\n" "${BASH_VERSION}" >&3
printf "\r\n" >&3
while read LINE <&3
do
# do something on $LINE
# or send $LINE to grep or awk for grabbing data
# or simply display back data with echo command
echo $LINE
done
```
See the bash man page for more information:
`man bash`
### A Note About GUI Tools and Cronjob
You need to request local display/input service using export DISPLAY=[user's machine]:0 command if you are [using cronjob][15] to call your scripts. For example, call /home/vivek/scripts/monitor.stock.sh as follows which uses zenity tool:
`@hourly DISPLAY=:0.0 /home/vivek/scripts/monitor.stock.sh`
Have a favorite UNIX tool to spice up shell script? Share it in the comments below.
### about the author
The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on [Twitter][16], [Facebook][17], [Google+][18].
--------------------------------------------------------------------------------
via: https://www.cyberciti.biz/tips/spice-up-your-unix-linux-shell-scripts.html
作者：[Vivek Gite][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.cyberciti.biz
[1]:https://www.cyberciti.biz/faq/ubuntu-lts-debian-linux-apt-command-examples/ (See Linux/Unix apt command examples for more info)
[2]:https://www.cyberciti.biz/tips/linux-debian-package-management-cheat-sheet.html (See Linux/Unix apt-get command examples for more info)
[3]:https://www.cyberciti.biz/faq/rhel-centos-fedora-linux-yum-command-howto/ (See Linux/Unix yum command examples for more info)
[4]:https://www.cyberciti.biz/media/new/tips/2010/04/notify-send.png (notify-send: Shell Script Get Or Send Desktop Notifications )
[5]:https://www.cyberciti.biz/media/new/tips/2010/04/notify-send-with-icons-timeout.png (Linux / UNIX: Display Notifications From Your Shell Scripts With notify-send)
[6]:https://www.cyberciti.biz/media/new/tips/2010/04/tput-options.png (Linux / UNIX Script Colours and Cursor Movement With tput)
[7]:https://bash.cyberciti.biz/guide/Zenity:_Shell_Scripting_with_Gnome
[8]:https://www.cyberciti.biz/media/new/tips/2010/04/zenity-outputs.png (zenity: Linux / UNIX display Dialogs Boxes From The Shell Scripts)
[9]:https://www.cyberciti.biz/media/new/tips/2010/04/KDialog.png (Kdialog: Suppressing the display of a dialog )
[10]:http://techbase.kde.org/Development/Tutorials/Shell_Scripting_with_KDE_Dialogs
[11]:https://bash.cyberciti.biz/guide/Bash_display_dialog_boxes
[12]:https://www.cyberciti.biz/tips/howto-linux-unix-write-to-syslog.html
[13]:https://www.cyberciti.biz/tips/freebsd-sending-a-message-to-windows-workstation.html
[14]:https://www.cyberciti.biz/faq/bash-for-loop/
[15]:https://www.cyberciti.biz/faq/how-do-i-add-jobs-to-cron-under-linux-or-unix-oses/
[16]:https://twitter.com/nixcraft
[17]:https://facebook.com/nixcraft
[18]:https://plus.google.com/+CybercitiBiz

2
sources/tech/20170628 Notes on BPF and eBPF.md
View File

@ -1,4 +1,4 @@
Notes on BPF & eBPF
translating by qhwdw Notes on BPF & eBPF
============================================================
Today it was Papers We Love, my favorite meetup! Today [Suchakra Sharma][6]([@tuxology][7] on twitter/github) gave a GREAT talk about the original BPF paper and recent work in Linux on eBPF. It really made me want to go write eBPF programs!

333
sources/tech/20170829 How To Set Up PF Firewall on FreeBSD to Protect a Web Server.md Normal file
View File

@ -0,0 +1,333 @@
How To Set Up PF Firewall on FreeBSD to Protect a Web Server
======
I am a new FreeBSD server user and moved from netfilter on Linux. How do I setup a firewall with PF on FreeBSD server to protect a web server with single public IP address and interface?
PF is an acronym for packet filter. It was created for OpenBSD but has been ported to FreeBSD and other operating systems. It is a stateful packet filtering engine. This tutorial will show you how to set up a firewall with PF on FreeBSD 10.x and 11.x server to protect your web server.
## Step 1 - Turn on PF firewall
You need to add the following three lines to /etc/rc.conf file:
```
# echo 'pf_enable="YES"' >> /etc/rc.conf
# echo 'pf_rules="/usr/local/etc/pf.conf"' >> /etc/rc.conf
# echo 'pflog_enable="YES"' >> /etc/rc.conf
# echo 'pflog_logfile="/var/log/pflog"' >> /etc/rc.conf
```
Where,
1. **pf_enable="YES"** - Turn on PF service.
2. **pf_rules="/usr/local/etc/pf.conf"** - Read PF rules from this file.
3. **pflog_enable="YES"** - Turn on logging support for PF.
4. **pflog_logfile="/var/log/pflog"** - File where pflogd should store the logfile i.e. store logs in /var/log/pflog file.
[![How To Set Up a Firewall with PF on FreeBSD to Protect a Web Server][1]][1]
## Step 2 - Creating firewall rules in /usr/local/etc/pf.conf
Type the following command:
```
# vi /usr/local/etc/pf.conf
```
Append the following PF rulesets :
```
# vim: set ft=pf
# /usr/local/etc/pf.conf
## Set your public interface ##
ext_if="vtnet0"
## Set your server public IP address ##
ext_if_ip="172.xxx.yyy.zzz"
## Set and drop these IP ranges on public interface ##
martians = "{ 127.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12, \
10.0.0.0/8, 169.254.0.0/16, 192.0.2.0/24, \
0.0.0.0/8, 240.0.0.0/4 }"
## Set http(80)/https (443) port here ##
webports = "{http, https}"
## enable these services ##
int_tcp_services = "{domain, ntp, smtp, www, https, ftp, ssh}"
int_udp_services = "{domain, ntp}"
## Skip loop back interface - Skip all PF processing on interface ##
set skip on lo
## Sets the interface for which PF should gather statistics such as bytes in/out and packets passed/blocked ##
set loginterface $ext_if
## Set default policy ##
block return in log all
block out all
# Deal with attacks based on incorrect handling of packet fragments
scrub in all
# Drop all Non-Routable Addresses
block drop in quick on $ext_if from $martians to any
block drop out quick on $ext_if from any to $martians
## Blocking spoofed packets
antispoof quick for $ext_if
# Open SSH port which is listening on port 22 from VPN 139.xx.yy.zz Ip only
# I do not allow or accept ssh traffic from ALL for security reasons
pass in quick on $ext_if inet proto tcp from 139.xxx.yyy.zzz to $ext_if_ip port = ssh flags S/SA keep state label "USER_RULE: Allow SSH from 139.xxx.yyy.zzz"
## Use the following rule to enable ssh for ALL users from any IP address #
## pass in inet proto tcp to $ext_if port ssh
### [ OR ] ###
## pass in inet proto tcp to $ext_if port 22
# Allow Ping-Pong stuff. Be a good sysadmin
pass inet proto icmp icmp-type echoreq
# All access to our Nginx/Apache/Lighttpd Webserver ports
pass proto tcp from any to $ext_if port $webports
# Allow essential outgoing traffic
pass out quick on $ext_if proto tcp to any port $int_tcp_services
pass out quick on $ext_if proto udp to any port $int_udp_services
# Add custom rules below
```
Save and close the file. PR [welcome here to improve rulesets][2]. To check for syntax error, run:
`# service pf check`
OR
`/etc/rc.d/pf check`
OR
`# pfctl -n -f /usr/local/etc/pf.conf `
## Step 3 - Start PF firewall
The commands are as follows. Be careful you might be disconnected from your server over ssh based session:
### Start PF
`# service pf start`
### Stop PF
`# service pf stop`
### Check PF for syntax error
`# service pf check`
### Restart PF
`# service pf restart`
### See PF status
`# service pf status`
Sample outputs:
```
Status: Enabled for 0 days 00:02:18 Debug: Urgent
Interface Stats for vtnet0 IPv4 IPv6
Bytes In 19463 0
Bytes Out 18541 0
Packets In
Passed 244 0
Blocked 3 0
Packets Out
Passed 136 0
Blocked 12 0
State Table Total Rate
current entries 1
searches 395 2.9/s
inserts 4 0.0/s
removals 3 0.0/s
Counters
match 19 0.1/s
bad-offset 0 0.0/s
fragment 0 0.0/s
short 0 0.0/s
normalize 0 0.0/s
memory 0 0.0/s
bad-timestamp 0 0.0/s
congestion 0 0.0/s
ip-option 0 0.0/s
proto-cksum 0 0.0/s
state-mismatch 0 0.0/s
state-insert 0 0.0/s
state-limit 0 0.0/s
src-limit 0 0.0/s
synproxy 0 0.0/s
map-failed 0 0.0/s
```
### Command to start/stop/restart pflog service
Type the following commands:
```
# service pflog start
# service pflog stop
# service pflog restart
```
## Step 4 - A quick introduction to pfctl command
You need to use the pfctl command to see PF ruleset and parameter configuration including status information from the packet filter. Let us see all common commands:
### Show PF rules information
`# pfctl -s rules`
Sample outputs:
```
block return in log all
block drop out all
block drop in quick on ! vtnet0 inet from 172.xxx.yyy.zzz/24 to any
block drop in quick inet from 172.xxx.yyy.zzz/24 to any
pass in quick on vtnet0 inet proto tcp from 139.aaa.ccc.ddd to 172.xxx.yyy.zzz/24 port = ssh flags S/SA keep state label "USER_RULE: Allow SSH from 139.aaa.ccc.ddd"
pass inet proto icmp all icmp-type echoreq keep state
pass out quick on vtnet0 proto tcp from any to any port = domain flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ntp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = smtp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = http flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = https flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ftp flags S/SA keep state
pass out quick on vtnet0 proto tcp from any to any port = ssh flags S/SA keep state
pass out quick on vtnet0 proto udp from any to any port = domain keep state
pass out quick on vtnet0 proto udp from any to any port = ntp keep state
```
#### Show verbose output for each rule
`# pfctl -v -s rules`
#### Add rule numbers with verbose output for each rule
`# pfctl -vvsr show`
#### Show state
```
# pfctl -s state
# pfctl -s state | more
# pfctl -s state | grep 'something'
```
### How to disable PF from the CLI
`# pfctl -d `
### How to enable PF from the CLI
`# pfctl -e `
### How to flush ALL PF rules/nat/tables from the CLI
`# pfctl -F all`
Sample outputs:
```
rules cleared
nat cleared
0 tables deleted.
2 states cleared
source tracking entries cleared
pf: statistics cleared
pf: interface flags reset
```
#### How to flush only the PF RULES from the CLI
`# pfctl -F rules `
#### How to flush only queue's from the CLI
`# pfctl -F queue `
#### How to flush all stats that are not part of any rule from the CLI
`# pfctl -F info`
#### How to clear all counters from the CLI
`# pfctl -z clear `
## Step 5 - See PF log
PF logs are in binary format. To see them type:
`# tcpdump -n -e -ttt -r /var/log/pflog`
Sample outputs:
```
Aug 29 15:41:11.757829 rule 0/(match) block in on vio0: 86.47.225.151.55806 > 45.FOO.BAR.IP.23: S 757158343:757158343(0) win 52206 [tos 0x28]
Aug 29 15:41:44.193309 rule 0/(match) block in on vio0: 5.196.83.88.25461 > 45.FOO.BAR.IP.26941: S 2224505792:2224505792(0) ack 4252565505 win 17520 (DF) [tos 0x24]
Aug 29 15:41:54.628027 rule 0/(match) block in on vio0: 45.55.13.94.50217 > 45.FOO.BAR.IP.465: S 3941123632:3941123632(0) win 65535
Aug 29 15:42:11.126427 rule 0/(match) block in on vio0: 87.250.224.127.59862 > 45.FOO.BAR.IP.80: S 248176545:248176545(0) win 28200 <mss 1410,sackOK,timestamp 1044055305 0,nop,wscale 8> (DF)
Aug 29 15:43:04.953537 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.7475: S 1164335542:1164335542(0) win 1024
Aug 29 15:43:05.122156 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.7475: R 1164335543:1164335543(0) win 1200
Aug 29 15:43:37.302410 rule 0/(match) block in on vio0: 94.130.12.27.18080 > 45.FOO.BAR.IP.64857: S 683904905:683904905(0) ack 4000841729 win 16384 <mss 1460>
Aug 29 15:44:46.574863 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.7677: S 3451987887:3451987887(0) win 1024
Aug 29 15:44:46.819754 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.7677: R 3451987888:3451987888(0) win 1200
Aug 29 15:45:21.194752 rule 0/(match) block in on vio0: 185.40.4.130.55910 > 45.FOO.BAR.IP.80: S 3106068642:3106068642(0) win 1024
Aug 29 15:45:32.999219 rule 0/(match) block in on vio0: 185.40.4.130.55910 > 45.FOO.BAR.IP.808: S 322591763:322591763(0) win 1024
Aug 29 15:46:30.157884 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6511: S 2412580953:2412580953(0) win 1024 [tos 0x28]
Aug 29 15:46:30.252023 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6511: R 2412580954:2412580954(0) win 1200 [tos 0x28]
Aug 29 15:49:44.337015 rule 0/(match) block in on vio0: 189.219.226.213.22640 > 45.FOO.BAR.IP.23: S 14807:14807(0) win 14600 [tos 0x28]
Aug 29 15:49:55.161572 rule 0/(match) block in on vio0: 5.196.83.88.25461 > 45.FOO.BAR.IP.40321: S 1297217585:1297217585(0) ack 1051525121 win 17520 (DF) [tos 0x24]
Aug 29 15:49:59.735391 rule 0/(match) block in on vio0: 36.7.147.209.2545 > 45.FOO.BAR.IP.3389: SWE 3577047469:3577047469(0) win 8192 <mss 1460,nop,wscale 8,nop,nop,sackOK> (DF) [tos 0x2 (E)]
Aug 29 15:50:00.703229 rule 0/(match) block in on vio0: 36.7.147.209.2546 > 45.FOO.BAR.IP.3389: SWE 1539382950:1539382950(0) win 8192 <mss 1460,nop,wscale 8,nop,nop,sackOK> (DF) [tos 0x2 (E)]
Aug 29 15:51:33.880334 rule 0/(match) block in on vio0: 45.55.22.21.53510 > 45.FOO.BAR.IP.2362: udp 14
Aug 29 15:51:34.006656 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6491: S 151489102:151489102(0) win 1024 [tos 0x28]
Aug 29 15:51:34.274654 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6491: R 151489103:151489103(0) win 1200 [tos 0x28]
Aug 29 15:51:36.393019 rule 0/(match) block in on vio0: 60.191.38.78.4249 > 45.FOO.BAR.IP.8000: S 3746478095:3746478095(0) win 29200 (DF)
Aug 29 15:51:57.213051 rule 0/(match) block in on vio0: 24.137.245.138.7343 > 45.FOO.BAR.IP.5358: S 14134:14134(0) win 14600
Aug 29 15:52:37.852219 rule 0/(match) block in on vio0: 122.226.185.125.51128 > 45.FOO.BAR.IP.23: S 1715745381:1715745381(0) win 5840 <mss 1420,sackOK,timestamp 13511417 0,nop,wscale 2> (DF)
Aug 29 15:53:31.309325 rule 0/(match) block in on vio0: 189.218.148.69.377 > 45.FOO.BAR.IP5358: S 65340:65340(0) win 14600 [tos 0x28]
Aug 29 15:53:31.809570 rule 0/(match) block in on vio0: 13.93.104.140.53184 > 45.FOO.BAR.IP.1433: S 39854048:39854048(0) win 1024
Aug 29 15:53:32.138231 rule 0/(match) block in on vio0: 13.93.104.140.53184 > 45.FOO.BAR.IP.1433: R 39854049:39854049(0) win 1200
Aug 29 15:53:41.459088 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6028: S 168338703:168338703(0) win 1024
Aug 29 15:53:41.789732 rule 0/(match) block in on vio0: 77.72.82.22.47218 > 45.FOO.BAR.IP.6028: R 168338704:168338704(0) win 1200
Aug 29 15:54:34.993594 rule 0/(match) block in on vio0: 212.47.234.50.5102 > 45.FOO.BAR.IP.5060: udp 408 (DF) [tos 0x28]
Aug 29 15:54:57.987449 rule 0/(match) block in on vio0: 51.15.69.145.5100 > 45.FOO.BAR.IP.5060: udp 406 (DF) [tos 0x28]
Aug 29 15:55:07.001743 rule 0/(match) block in on vio0: 190.83.174.214.58863 > 45.FOO.BAR.IP.23: S 757158343:757158343(0) win 27420
Aug 29 15:55:51.269549 rule 0/(match) block in on vio0: 142.217.201.69.26112 > 45.FOO.BAR.IP.22: S 757158343:757158343(0) win 22840 <mss 1460>
Aug 29 15:58:41.346028 rule 0/(match) block in on vio0: 169.1.29.111.29765 > 45.FOO.BAR.IP.23: S 757158343:757158343(0) win 28509
Aug 29 15:59:11.575927 rule 0/(match) block in on vio0: 187.160.235.162.32427 > 45.FOO.BAR.IP.5358: S 22445:22445(0) win 14600 [tos 0x28]
Aug 29 15:59:37.826598 rule 0/(match) block in on vio0: 94.74.81.97.54656 > 45.FOO.BAR.IP.3128: S 2720157526:2720157526(0) win 1024 [tos 0x28]
Aug 29 15:59:37.991171 rule 0/(match) block in on vio0: 94.74.81.97.54656 > 45.FOO.BAR.IP.3128: R 2720157527:2720157527(0) win 1200 [tos 0x28]
Aug 29 16:01:36.990050 rule 0/(match) block in on vio0: 182.18.8.28.23299 > 45.FOO.BAR.IP.445: S 1510146048:1510146048(0) win 16384
```
To see live log run:
`# tcpdump -n -e -ttt -i pflog0`
For more info the [PF FAQ][3], [FreeBSD HANDBOOK][4] and the following man pages:
```
# man tcpdump
# man pfctl
# man pf
```
## about the author:
The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on [Twitter][5], [Facebook][6], [Google+][7].
--------------------------------------------------------------------------------
via: https://www.cyberciti.biz/faq/how-to-set-up-a-firewall-with-pf-on-freebsd-to-protect-a-web-server/
作者：[Vivek Gite][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.cyberciti.biz
[1]:https://www.cyberciti.biz/media/new/faq/2017/08/howto-setup-a-firewall-with-pf-on-freebsd.001.jpeg
[2]:https://github.com/nixcraft/pf.conf/blob/master/pf.conf
[3]:https://www.openbsd.org/faq/pf/
[4]:https://www.freebsd.org/doc/handbook/firewalls.html
[5]:https://twitter.com/nixcraft
[6]:https://facebook.com/nixcraft
[7]:https://plus.google.com/+CybercitiBiz

172
sources/tech/20171207 How To Find Files Based On their Permissions.md
View File

@ -1,172 +0,0 @@
translated by cyleft
How To Find Files Based On their Permissions
======
Finding files in Linux is not a big deal. There are plenty of free and open source graphical utilities available on the market. In my opinion, finding files from command line is much easier and faster. We already knew how to [**find and sort files based on access and modification date and time**][1]. Today, we will see how to find files based on their permissions in Unix-like operating systems.
For the purpose of this guide, I am going to create three files namely **file1** , **file2** and **file3** with permissions **777** , **766** , **655** respectively in a folder named **ostechnix**.
```
mkdir ostechnix && cd ostechnix/
```
```
install -b -m 777 /dev/null file1
```
```
install -b -m 766 /dev/null file2
```
```
install -b -m 655 /dev/null file3
```
[![][2]][3]
Now let us find the files based on their permissions.
### Find files Based On their Permissions
The typical syntax to find files based on their permissions is:
```
find -perm mode
```
The MODE can be either with numeric or octal permission (like 777, 666.. etc) or symbolic permission (like u=x, a=r+x).
Before going further, we can specify the MODE in three different ways.
1. If we specify the mode without any prefixes, it will find files of **exact** permissions.
2. If we use **" -"** prefix with mode, at least the files should have the given permission, not the exact permission.
3. If we use **" /"** prefix, either the owner, the group, or other should have permission to the file.
Allow me to explain with some examples, so you can understand better.
First, we will see finding files based on numeric permissions.
### Find Files Based On their Numeric (octal) Permissions
Now let me run the following command:
```
find -perm 777
```
This command will find the files with permission of **exactly 777** in the current directory.
[![][2]][4]
As you see in the above output, file1 is the only one that has **exact 777 permission**.
Now, let us use "-" prefix and see what happens.
```
find -perm -766
```
[![][2]][5]
As you see, the above command displays two files. We have set 766 permission to file2, but this command displays two files, why? Because, here we have used "-" prefix". It means that this command will find all files where the file owner has read/write/execute permissions, file group members have read/write permissions and everything else has also read/write permission. In our case, file1 and file2 have met this criteria. In other words, the files need not to have exact 766 permission. It will display any files that falls under this 766 permission.
Next, we will use "/" prefix and see what happens.
```
find -perm /222
```
[![][2]][6]
The above command will find files which are writable by somebody (either their owner, or their group, or anybody else). Here is another example.
```
find -perm /220
```
This command will find files which are writable by either their owner or their group. That means the files **don 't have to be writable** by **both the owner and group** to be matched; **either** will do.
But if you run the same command with "-" prefix, you will only see the files only which are writable by both owner and group.
```
find -perm -220
```
The following screenshot will show you the difference between these two prefixes.
[![][2]][7]
Like I already said, we can also use symbolic notation to represent the file permissions.
Also read:
### Find Files Based On their Permissions using symbolic notation
In the following examples, we use symbolic notations such as **u** ( for user), **g** (group), **o** (others). We can also use the letter **a** to represent all three of these categories. The permissions can be specified using letters **r** (read), **w** (write), **x** (executable).
For instance, to find any file with group **write** permission, run:
```
find -perm -g=w
```
[![][2]][8]
As you see in the above example, file1 and file2 have group **write** permission. Please note that you can use either "=" or "+" for symbolic notation. It doesn't matter. For example, the following two commands do the same thing.
```
find -perm -g=w
find -perm -g+w
```
To find any file which are writable by the file owner, run:
```
find -perm -u=w
```
To find any file which are writable by all (the file owner, group and everyone else), run:
```
find -perm -a=w
```
To find files which are writable by **both** their **owner** and their **group** , use this command:
```
find -perm -g+w,u+w
```
The above command is equivalent of "find -perm -220" command.
To find files which are writable by **either** their **owner** or their **group** , run:
```
find -perm /u+w,g+w
```
Or,
```
find -perm /u=w,g=w
```
These two commands does the same job as "find -perm /220" command.
For more details, refer the man pages.
```
man find
```
Also, check the [**man pages alternatives**][9] to learn more simplified examples of any Linux command.
And, that's all for now folks. I hope this guide was useful. More good stuffs to come. Stay tuned.
Cheers!
--------------------------------------------------------------------------------
via: https://www.ostechnix.com/find-files-based-permissions/
作者：[][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.ostechnix.com
[1] https://www.ostechnix.com/find-sort-files-based-access-modification-date-time-linux/
[2] data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
[3] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-1-1.png ()
[4] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-2.png ()
[5] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-3.png ()
[6] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-6.png ()
[7] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-7.png ()
[8] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-8.png ()
[9] https://www.ostechnix.com/3-good-alternatives-man-pages-every-linux-user-know/

4
sources/tech/20171212 How To Count The Number Of Files And Folders-Directories In Linux.md
View File

@ -1,5 +1,8 @@
translating by Flowsnow
How To Count The Number Of Files And Folders/Directories In Linux
======
Hi folks, today again we came with set of tricky commands that help you in many ways. It's kind of manipulation commands which help you to count files and directories in the current directory, recursive count, list of files created by particular user, etc,.
In this tutorial, we are going to show you, how to use more than one command like, all together to perform some advanced actions using ls, egrep, wc and find command. The below set of commands which helps you in many ways.
@ -164,7 +167,6 @@ To experiment this, i'm going to create totally 7 files and 2 folders (5 regular
```
--------------------------------------------------------------------------------
via: https://www.2daygeek.com/how-to-count-the-number-of-files-and-folders-directories-in-linux/

1
sources/tech/20180102 Best open source tutorials in 2017.md
View File

@ -1,3 +1,4 @@
Translating zjon
Best open source tutorials in 2017
======
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/osdc-lead-teacher-learner.png?itok=rMJqBN5G)

88
sources/tech/20180104 How to Change Your Linux Console Fonts.md
View File

@ -1,88 +0,0 @@
translating by lujun9972
How to Change Your Linux Console Fonts
======
![](https://www.linux.com/sites/lcom/files/styles/rendered_file/public/font-size_0.png?itok=d97vmyYa)
I try to be a peaceful soul, but some things make that difficult, like tiny console fonts. Mark my words, friends, someday your eyes will be decrepit and you won't be able to read those tiny fonts you coded into everything, and then you'll be sorry, and I will laugh.
Fortunately, Linux fans, you can change your console fonts. As always, the ever-changing Linux landscape makes this less than straightforward, and font management on Linux is non-existent, so we'll muddle along as best we can. In this article, I'll show what I've found to be the easiest approach.
### What is the Linux Console?
Let us first clarify what we're talking about. When I say Linux console, I mean TTY1-6, the virtual terminals that you access from your graphical desktop with Ctrl+Alt+F1 through F6. To get back to your graphical environment, press Alt+F7. (This is no longer universal, however, and your Linux distribution may have it mapped differently. You may have more or fewer TTYs, and your graphical session may not be at F7. For example, Fedora puts the default graphical session at F2, and an extra one at F1.) I think it is amazingly cool that we can have both X and console sessions running at the same time.
The Linux console is part of the kernel, and does not run in an X session. This is the same console you use on headless servers that have no graphical environments. I call the terminals in a graphical session X terminals, and terminal emulators is my catch-all name for both console and X terminals.
But that's not all. The Linux console has come a long way from the early ANSI days, and thanks to the Linux framebuffer, it has Unicode and limited graphics support. There are also a number of console multimedia applications that we will talk about in a future article.
### Console Screenshots
The easy way to get console screenshots is from inside a virtual machine. Then you can use your favorite graphical screen capture program from the host system. You may also make screen captures from your console with [fbcat][1] or [fbgrab][2]. `fbcat` creates a portable pixmap format (PPM) image; this is a highly portable uncompressed image format that should be readable on any operating system, and of course you can convert it to whatever format you want. `fbgrab` is a wrapper script to `fbcat` that creates a PNG file. There are multiple versions of `fbgrab` written by different people floating around. Both have limited options and make only a full-screen capture.
`fbcat` needs root permissions, and must redirect to a file. Do not specify a file extension, but only the filename:
```
$ sudo fbcat > Pictures/myfile
```
After cropping in GIMP, I get Figure 1.
It would be nice to have a little padding on the left margin, so if any of you excellent readers know how to do this, please tell us in the comments.
`fbgrab` has a few more options that you can read about in `man fbgrab`, such as capturing a different console, and time delay. This example makes a screen grab just like `fbcat`, except you don't have to explicitly redirect:
```
$ sudo fbgrab Pictures/myOtherfile
```
### Finding Fonts
As far as I know, there is no way to list your installed kernel fonts other than looking in the directories they are stored in: `/usr/share/consolefonts/` (Debian/etc.), `/lib/kbd/consolefonts/` (Fedora), `/usr/share/kbd/consolefonts` (openSUSE)...you get the idea.
### Changing Fonts
Readable fonts are not a new concept. Embrace the old! Readability matters. And so does configurability, which sometimes gets lost in the rush to the new-shiny.
On Debian/Ubuntu/etc. systems you can run `sudo dpkg-reconfigure console-setup` to set your console font, then run the `setupcon` command in your console to activate the changes. `setupcon` is part of the `console-setup` package. If your Linux distribution doesn't include it, there might be a package for you at [openSUSE][3].
You can also edit `/etc/default/console-setup` directly. This example sets the Terminus Bold font at 32 points, which is my favorite, and restricts the width to 80 columns.
```
ACTIVE_CONSOLES="/dev/tty[1-6]"
CHARMAP="UTF-8"
CODESET="guess"
FONTFACE="TerminusBold"
FONTSIZE="16x32"
SCREEN_WIDTH="80"
```
The FONTFACE and FONTSIZE values come from the font's filename, `TerminusBold32x16.psf.gz`. Yes, you have to know to reverse the order for FONTSIZE. Computers are so much fun. Run `setupcon` to apply the new configuration. You can see the whole character set for your active font with `showconsolefont`. Refer to `man console-setup` for complete options.
### Systemd
Systemd is different from `console-setup`, and you don't need to install anything, except maybe some extra font packages. All you do is edit `/etc/vconsole.conf` and then reboot. On my Fedora and openSUSE systems I had to install some extra Terminus packages to get the larger sizes as the installed fonts only went up to 16 points, and I wanted 32. This is the contents of `/etc/vconsole.conf` on both systems:
```
KEYMAP="us"
FONT="ter-v32b"
```
Come back next week to learn some more cool console hacks, and some multimedia console applications.
Learn more about Linux through the free ["Introduction to Linux" ][4]course from The Linux Foundation and edX.
--------------------------------------------------------------------------------
via: https://www.linux.com/learn/intro-to-linux/2018/1/how-change-your-linux-console-fonts
作者：[Carla Schroder][a]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.linux.com/users/cschroder
[1]:http://jwilk.net/software/fbcat
[2]:https://github.com/jwilk/fbcat/blob/master/fbgrab
[3]:https://software.opensuse.org/package/console-setup
[4]:https://training.linuxfoundation.org/linux-courses/system-administration-training/introduction-to-linux

147
sources/tech/20180110 Best Linux Screenshot and Screencasting Tools.md Normal file
View File

@ -0,0 +1,147 @@
Best Linux Screenshot and Screencasting Tools
======
![](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/best-linux-screenshot-and-screencasting-tools_orig.jpg)
There comes a time you want to capture an error on your screen and send it to the developers or want help from _Stack Overflow,_ you need the right tools to take that screenshot and save it or send it. There are tools in the form of programs and others as shell extensions for GNOME. Not to worry, here are the best Linux Screenshot taking tools that you can use to take those screenshots or make a screencast.
## Best Linux Screenshot Or Screencasting Tools
### 1\. Shutter
[![shutter linux screenshot taking tools](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/shutter-linux-screenshot-taking-tools_orig.jpg)][2]
[Shutter][3] is one of the best Linux screenshot taking tools. It has the advantage of taking different screenshots depending on what you want to take on your screen. After you take the screenshot, it allows you to see the screenshot before saving it after you take the screenshot. It also includes an extension menu that shows up on your top panel for GNOME. That makes accessing the app much easier and much convenient for anyone to use.
​You can take screenshots of a selection, a window, desktop, window under cursor, section, menu, tooltip or web. Shutter allows you to upload the screenshots directly to the cloud using the preferred cloud services provider. This Linux tool also allows you to edit your screenshots before you save them. It also comes with plugins that you can add or remove.
To install it, you will have to type the following in the terminal:
```
sudo add-apt-repository -y ppa:shutter/ppa
sudo apt-get update && sudo apt-get install shutter
```
### 2. Vokoscreen
[![vokoscreen screencasting tool for linux](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/vokoscreen-screencasting-tool-for-linux_orig.jpg)][4]
[Vokoscreen][5] is an app that allows you to record your screen as you show around and narrate what you are doing on the screen. It is easy to use, has a simple interface and includes a top panel menu for easy access when you are recording your screen.
​
You can choose to record the whole screen, a window or just a selection of an area. Customizing the recording is easy to get the type of screen recording you want to achieve. Vokoscreen even allows you to create a gif as a screen recording. You can also record yourself using the webcam in case you were narrating as tutorials so that you can engage the learners. Once you are done, you can playback the recording right from the application so that you don’t have to keep navigating to find the recording.
[![vokoscreen preferences](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/vokoscreen-preferences_orig.jpg)][6]
You can install Vocoscreen from your distro repository. Or download the package from [pkgs.org][7] , select the Linux distro you are using.
```
sudo dpkg -i vokoscreen_2.5.0-1_amd64.deb
```
### 3. OBS
[![obs linux screencasting tool](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/obs-linux-screencasting-tool_orig.jpg)][8]
[OBS][9] can be used to record your screen as well as record streams from the internet. It allows you to see whatever you are recording as you stream or as you narrate your screen recording. It allows you to choose the quality of your recording according to your preferences. It also allows you to choose the type of file you want your recording to save to. In addition to the feature of recording, you can switch to Studio mode allowing you to edit your recording to make a complete video without having to use any other external editing software. To install OBS in your Linux distribution, you must have FFmpeg installed on your machine. To install FFmpeg type the following in the terminal for ubuntu 14.04 and earlier:
```
sudo add-apt-repository ppa:kirillshkrogalev/ffmpeg-next
sudo apt-get update && sudo apt-get install ffmpeg
```
​For ubuntu 15.04 and later you can just type the following in the terminal to install FFmpeg:
```
sudo apt-get install ffmpeg
```
​If you have already installed FFmpeg, type the following in the terminal to install OBS:
```
sudo add-apt-repository ppa:obsproject/obs-studio
sudo apt-get update
sudo apt-get install obs-studio
```
### 4. Green Recorder
[![green recording linux tool](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/green-recording-linux-tool_orig.jpg)][10]
[Green recorder][11] is a simple interface based program that allows you to record the screen. You can choose what to record including video or just audio and allow you to show the mouse pointer and even follow it as you record your screen. You can record a window or just a selected area on your screen so that only what you want to record shows up in your recording. You can customize the number of frames to record in your final video. In case you want to start recording after a delay, you have the option to configure the delay you wish to set. You have the option to run a command after the recording is done that will run on your machine immediately after you stop recording.
​
To install green recorder, type the following in the terminal:
```
sudo add-apt-repository ppa:fossproject/ppa
sudo apt update && sudo apt install green-recorder
```
### 5. Kazam
[![kazam screencasting tool for linux](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/kazam-screencasting-tool-for-linux_orig.jpg)][12]
[Kazam][13] Linux screenshot tool is very popular amongst Linux users. It is an intuitive simple to use app that allows you to take a screencast or a screenshot allowing you to customise the delay before taking a screencast or screenshot. It allows you to select the area, window or fullscreen you want to capture. Kazam’s interface is well laid out and not as complicated as other apps. Its features will leave you happy about taking your screenshots. Kazam also includes a system tray icon and menu that allows you to take the screenshot without going to the application itself.
​​
To install Kazam, type the following in the terminal:
```
sudo apt-get install kazam
```
​If the PPA is not found, you can install it manually using the following commands:
```
sudo add-apt-repository ppa:kazam-team/stable-series
sudo apt-get update && sudo apt-get install kazam
```
### 6. Screenshot tool GNOME extension
[![gnome screenshot extension](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/gnome-screenshot-extension-compressed_orig.jpg)][1]
There is a GNOME extension just named screenshot tool that always shows up on the system panel until you disable it. It is convenient since it just sits on the system panel until you will trigger it to take a screenshot. The main advantage of this tool is that it is the quickest to access since it is always in your system panel unless you deactivate it in the tweak utility tool. The tool also has a preferences window allowing you to tweak it to your preferences. To install it on your GNOME desktop, head to extensions.gnome.org and search for “_Screenshot Tool”._
You must have the gnome extensions chrome extension installed as well as GNOME tweaks tool installed to use the tool.
[![gnome screenshot extension preferences](http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/gnome-screenshot-extension-preferences_orig.jpg)][14]
The **Linux screenshot tools** are quite helpful especially when you don’t know what to do when you come across a problem and want to share the error with [the Linux community][15] or the developers of a program that you are using. Learning developers or programmers or anyone else need it will find these tools useful to share your screenshots. Youtubers and tutorial makers will find the screencasting tools even more useful when they use them to record their tutorials and post them.​
--------------------------------------------------------------------------------
via: http://www.linuxandubuntu.com/home/best-linux-screenshot-screencasting-tools
作者：[linuxandubuntu][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:http://www.linuxandubuntu.com
[1]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/gnome-screenshot-extension-compressed_orig.jpg
[2]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/shutter-linux-screenshot-taking-tools_orig.jpg
[3]:http://shutter-project.org/
[4]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/vokoscreen-screencasting-tool-for-linux_orig.jpg
[5]:https://github.com/vkohaupt/vokoscreen
[6]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/vokoscreen-preferences_orig.jpg
[7]:https://pkgs.org/download/vokoscreen
[8]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/obs-linux-screencasting-tool_orig.jpg
[9]:https://obsproject.com/
[10]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/green-recording-linux-tool_orig.jpg
[11]:https://github.com/foss-project/green-recorder
[12]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/kazam-screencasting-tool-for-linux_orig.jpg
[13]:https://launchpad.net/kazam
[14]:http://www.linuxandubuntu.com/uploads/2/1/1/5/21152474/gnome-screenshot-extension-preferences_orig.jpg
[15]:http://www.linuxandubuntu.com/home/top-10-communities-to-help-you-learn-linux

2
sources/tech/20180111 Multimedia Apps for the Linux Console.md
View File

@ -1,3 +1,5 @@
Translating by Yinr
Multimedia Apps for the Linux Console
======

112
sources/tech/20180111 The Fold Command Tutorial With Examples For Beginners.md
View File

@ -1,112 +0,0 @@
The Fold Command Tutorial With Examples For Beginners
======
![](https://www.ostechnix.com/wp-content/uploads/2018/01/Fold-Command-2-720x340.png)
Have you ever found yourself in a situation where you want to fold or break the output of a command to fit within a specific width? I have find myself in this situation few times while running VMs, especially the servers with no GUI. Just in case, if you ever wanted to limit the output of a command to a particular width, look nowhere! Here is where **fold** command comes in handy! The fold command wraps each line in an input file to fit a specified width and prints it to the standard output.
In this brief tutorial, we are going to see the usage of fold command with practical examples.
### The Fold Command Tutorial With Examples
Fold command is the part of GNU coreutils package, so let us not bother about installation.
The typical syntax of fold command:
```
fold [OPTION]... [FILE]...
```
Allow me to show you some examples, so you can get a better idea about fold command. I have a file named **linux.txt** with some random lines.
[![][1]][2]
To wrap each line in the above file to default width, run:
```
fold linux.txt
```
**80** columns per line is the default width. Here is the output of above command:
[![][1]][3]
As you can see in the above output, fold command has limited the output to a width of 80 characters.
Of course, we can specify your preferred width, for example 50, like below:
```
fold -w50 linux.txt
```
Sample output would be:
[![][1]][4]
Instead of just displaying output, we can also write the output to a new file as shown below:
```
fold -w50 linux.txt > linux1.txt
```
The above command will wrap the lines of **linux.txt** to a width of 50 characters, and writes the output to new file named **linux1.txt**.
Let us check the contents of the new file:
```
cat linux1.txt
```
[![][1]][5]
Did you closely notice the output of the previous commands? Some words are broken between lines. To overcome this issue, we can use -s flag to break the lines at spaces.
The following command wraps each line in a given file to width "50" and breaks the line at spaces:
```
fold -w50 -s linux.txt
```
Sample output:
[![][1]][6]
See? Now, the output is much clear. This command puts each space separated word in a new line and words with length > 50 are wrapped.
In all above examples, we limited the output width by columns. However, we can enforce the width of the output to the number of bytes specified using **-b** option. The following command breaks the output at 20 bytes.
```
fold -b20 linux.txt
```
Sample output:
[![][1]][7]
**Also read:**
+ [The Uniq Command Tutorial With Examples For Beginners][8]
For more details, refer the man pages.
```
man fold
```
And, that's for now folks. You know now how to use fold command to limit the output of a command to fit in a specific width. I hope this was useful. We will be posting more useful guides everyday. Stay tuned!
Cheers!
--------------------------------------------------------------------------------
via: https://www.ostechnix.com/fold-command-tutorial-examples-beginners/
作者：[SK][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.ostechnix.com/author/sk/
[1]:data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
[2]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-1.png ()
[3]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-2.png ()
[4]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-3-1.png ()
[5]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-4.png ()
[6]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-5-1.png ()
[7]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-6-1.png ()
[8]:https://www.ostechnix.com/uniq-command-tutorial-examples-beginners/

121
sources/tech/20180111 The open organization and inner sourcing movements can share knowledge.md Normal file
View File

@ -0,0 +1,121 @@
The open organization and inner sourcing movements can share knowledge
======
![](https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/gov_collaborative_risk.png?itok=we8DKHuL)
Image by : opensource.com
Red Hat is a company with roughly 11,000 employees. The IT department consists of roughly 500 members. Though it makes up just a fraction of the entire organization, the IT department is still sufficiently staffed to have many application service, infrastructure, and operational teams within it. Our purpose is "to enable Red Hatters in all functions to be effective, productive, innovative, and collaborative, so that they feel they can make a difference,"--and, more specifically, to do that by providing technologies and related services in a fashion that is as open as possible.
Being open like this takes time, attention, and effort. While we always strive to be as open as possible, it can be difficult. For a variety of reasons, we don't always succeed.
In this story, I'll explain a time when, in the rush to innovate, the Red Hat IT organization lost sight of its open ideals. But I'll also explore how returning to those ideals--and using the collaborative tactics of "inner source"--helped us to recover and greatly improve the way we deliver services.
### About inner source
Before I explain how inner source helped our team, let me offer some background on the concept.
Inner source is the adoption of open source development practices between teams within an organization to promote better and faster delivery without requiring project resources be exposed to the world or openly licensed. It allows an organization to receive many of the benefits of open source development methods within its own walls.
In this way, inner source aligns well with open organization strategies and principles; it provides a path for open, collaborative development. While the open organization defines its principles of openness broadly as transparency, inclusivity, adaptability, collaboration, and community--and covers how to use these open principles for communication, decision making, and many other topics--inner source is about the adoption of specific and tactical practices, processes, and patterns from open source communities to improve delivery.
For instance, [the Open Organization Maturity Model][1] suggests that in order to be transparent, teams should, at minimum, share all project resources with the project team (though it suggests that it's generally better to share these resources with the entire organization). The common pattern in both inner source and open source development is to host all resources in a publicly available version control system, for source control management, which achieves the open organization goal of high transparency.
Inner source aligns well with open organization strategies and principles.
Another example of value alignment appears in the way open source communities accept contributions. In open source communities, source code is transparently available. Community contributions in the form of patches or merge requests are commonly accepted practices (even expected ones). This provides one example of how to meet the open organization's goal of promoting inclusivity and collaboration.
### The challenge
Early in 2014, Red Hat IT began its first steps toward making Amazon Web Services (AWS) a standard hosting offering for business critical systems. While teams within Red Hat IT had built several systems and services in AWS by this time, these were bespoke creations, and we desired to make deploying services to IT standards in AWS both simple and standardized.
In order to make AWS cloud hosting meet our operational standards (while being scalable), the Cloud Enablement team within Red Hat IT decided that all infrastructure in AWS would be configured through code, rather than manually, and that everyone would use a standard set of tools. The Cloud Enablement team designed and built these standard tools; a separate group, the Platform Operations team, was responsible for provisioning and hosting systems and services in AWS using the tools.
The Cloud Enablement team built a toolset, obtusely named "Template Util," based on AWS Cloud Formations configurations wrapped in a management layer to enforce certain configuration requirements and make stamping out multiple copies of services across environments easier. While the Template Util toolset technically met all our initial requirements, and we eventually provisioned the infrastructure for more than a dozen services with it, engineers in every team working with the tool found using it to be painful. Michael Johnson, one engineer using the tool, said "It made doing something relatively straightforward really complicated."
Among the issues Template Util exhibited were:
* Underlying cloud formations technologies implied constraints on application stack management at odds with how we managed our application systems.
* The tooling was needlessly complex and brittle in places, using multiple layered templating technologies and languages making syntax issues hard to debug.
* The code for the tool--and some of the data users needed to manipulate the tool--were kept in a repository that was difficult for most users to access.
* There was no standard process to contributing or accepting changes.
* The documentation was poor.
As more engineers attempted to use the Template Util toolset, they found even more issues and limitations with the tools. Unhappiness continued to grow. To make matters worse, the Cloud Enablement team then shifted priorities to other deliverables without relinquishing ownership of the tool, so bug fixes and improvements to the tools were further delayed.
The real, core issues here were our inability to build an inclusive community to collaboratively build shared tooling that met everyone's needs. Fear of losing "ownership," fear of changing requirements, and fear of seeing hard work abandoned all contributed to chronic conflict, which in turn led to poorer outcomes.
### Crisis point
By September 2015, more than a year after launching our first major service in AWS with the Template Util tool, we hit a crisis point.
Many engineers refused to use the tools. That forced all of the related service provisioning work on a small set of engineers, further fracturing the community and disrupting service delivery roadmaps as these engineers struggled to deal with unexpected work. We called an emergency meeting and invited all the teams involved to find a solution.
During the emergency meeting, we found that people generally thought we needed immediate change and should start the tooling effort over, but even the decision to start over wasn't unanimous. Many solutions emerged--sometimes multiple solutions from within a single team--all of which would require significant work to implement. While we couldn't reach a consensus on which solution to use during this meeting, we did reach an agreement to give proponents of different technologies two weeks to work together, across teams, to build their case with a prototype, which the community could then review.
While we didn't reach a final and definitive decision, this agreement was the first point where we started to return to the open source ideals that guide our mission. By inviting all involved parties, we were able to be transparent and inclusive, and we could begin rebuilding our internal community. By making clear that we wanted to improve things and were open to new options, we showed our commitment to adaptability and meritocracy. Most importantly, the plan for building prototypes gave people a clear, return path to collaboration.
When the community reviewed the prototypes, it determined that the clear leader was an Ansible-based toolset that would eventually become known, internally, as Ansicloud. (At the time, no one involved with this work had any idea that Red Hat would acquire Ansible the following month. It should also be noted that other teams within Red Hat have found tools based on Cloud Formation extremely useful, even when our specific Template Util tool did not find success.)
This prototyping and testing phase didn't fix things overnight, though. While we had consensus on the general direction we needed to head, we still needed to improve the new prototype to the point at which engineers could use it reliably for production services.
So over the next several months, a handful of engineers worked to further build and extend the Ansicloud toolset. We built three new production services. While we were sharing code, that sharing activity occurred at a low level of maturity. Some engineers had trouble getting access due to older processes. Other engineers headed in slightly different directions, with each engineer having to rediscover some of the core design issues themselves.
### Returning to openness
This led to a turning point: Building on top of the previous agreement, we focused on developing a unified vision and providing easier access. To do this, we:
1. created a list of specific goals for the project (both "must-haves" and "nice-to-haves"),
2. created an open issue log for the project to avoid solving the same problem repeatedly,
3. opened our code base so anyone in Red Hat could read or clone it, and
4. made it easy for engineers to get trusted committer access
Our agreement to collaborate, our finally unified vision, and our improved tool development methods spurred the growth of our community. Ansicloud adoption spread throughout the involved organizations, but this led to a new problem: The tool started changing more quickly than users could adapt to it, and improvements that different groups submitted were beginning to affect other groups in unanticipated ways.
These issues resulted in our recent turn to inner source practices. While every open source project operates differently, we focused on adopting some best practices that seemed common to many of them. In particular:
* We identified the business owner of the project and the core-contributor group of developers who would govern the development of the tools and decide what contributions to accept. While we want to keep things open, we can't have people working against each other or breaking each other's functionality.
* We developed a project README clarifying the purpose of the tool and specifying how to use it. We also created a CONTRIBUTING document explaining how to contribute, what sort of contributions would be useful, and what sort of tests a contribution would need to pass to be accepted.
* We began building continuous integration and testing services for the Ansicloud tool itself. This helped us ensure we could quickly and efficiently validate contributions technically, before the project accepted and merged them.
With these basic agreements, documents, and tools available, we were back onto the path of open collaboration and successful inner sourcing.
### Why it matters
Why does inner source matter?
From a developer community point of view, shifting from a traditional siloed development model to the inner source model has produced significant, quantifiable improvements:
* Contributions to our tooling have grown 72% per week (by number of commits).
* The percentage of contributions from non-core committers has grown from 27% to 78%; the users of the toolset are driving its development.
* The contributor list has grown by 15%, primarily from new users of the tool set, rather than core committers, increasing our internal community.
And the tools we've delivered through this project have allowed us to see dramatic improvements in our business outcomes. Using the Ansicloud tools, 54 new multi-environment application service deployments were created in 385 days (compared to 20 services in 1,013 days with the Template Util tools). We've gone from one new service deployment in a 50-day period to one every week--a seven-fold increase in the velocity of our delivery.
What really matters here is that the improvements we saw were not aberrations. Inner source provides common, easily understood patterns that organizations can adopt to effectively promote collaboration (not to mention other open organization principles). By mirroring open source production practices, inner source can also mirror the benefits of open source code, which have been seen time and time again: higher quality code, faster development, and more engaged communities.
This article is part of the [Open Organization Workbook project][2].
### about the author
Tom Benninger - Tom Benninger is a Solutions Architect, Systems Engineer, and continual tinkerer at Red Hat, Inc. Having worked with startups, small businesses, and larger enterprises, he has experience within a broad set of IT disciplines. His current area of focus is improving Application Lifecycle Management in the enterprise. He has a particular interest in how open source, inner source, and collaboration can help support modern application development practices and the adoption of DevOps, CI/CD, Agile,...
--------------------------------------------------------------------------------
via: https://opensource.com/open-organization/18/1/open-orgs-and-inner-source-it
作者：[Tom Benninger][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://opensource.com/users/tomben
[1]:https://opensource.com/open-organization/resources/open-org-maturity-model
[2]:https://opensource.com/open-organization/17/8/workbook-project-announcement

80
sources/tech/20180114 Playing Quake 4 on Linux in 2018.md Normal file
View File

@ -0,0 +1,80 @@
Playing Quake 4 on Linux in 2018
======
A few months back [I wrote an article][1] outlining the various options Linux users now have for playing Doom 3, as well as stating which of the three contenders I felt to be the best option in 2017. Having already gone to the trouble of getting the original Doom 3 binary working on my modern Arch Linux system, it made me wonder just how much effort it would take to get the closed source Quake 4 port up and running again as well.
### Getting it running
[![][2]][3] [![][4]][5]
Quake 4 was ported to Linux by Timothee Besset in 2005, although the binaries themselves were later taken down along with the rest of the id Software FTP server by ZeniMax. The original [Linux FAQ page][6] is still online though, and mirrors hosting the Linux installer still exist, such as [this one][7] ran by the fan website [Quaddicted][8]. Once downloaded this will give you a graphical installer which will install the game binary without any of the game assets.
These will need to be taken from either the game discs of a retail Windows version as I did, or taken from an already installed Windows version of the game such as from [Steam][9]. Follow the steps in the Linux FAQ to the letter for best results. Please note that the [GOG.com][10] release of Quake 4 is unique in not supplying a valid CD key, something which is still required for the Linux port to launch. There are [ways to get around this][11], but we only condone these methods for legitimate purchasers.
Like with Doom 3 I had to remove the libgcc_s.so.1, libSDL-1.2.id.so.0, and libstdc++.so.6 libraries that the game came with in the install directory in order to get it to run. I also ran into the same sound issue I had with Doom 3, meaning I had to modify the Quake4Config.cfg file located in the hidden ~/.quake4/q4base directory in the same fashion as before. However, this time I ran into a whole host of other issues that made me have to modify the configuration file as well.
First off the language the game wanted to use would always default to Spanish, meaning I had to manually tell the game to use English instead. I also ran into a known issue on all platforms wherein the game would not properly recognize the available VRAM on modern graphics cards, and as such would force the game to use lower image quality settings. Quake 4 will also not render see-through surfaces unless anti-aliasing is enabled, although going beyond 8x caused the game not to load for me.
Appending the following to the end of the Quake4Config.cfg file resolved all of my issues:
```
seta image_downSize "0"
seta image_downSizeBump "0"
seta image_downSizeSpecular "0"
seta image_filter "GL_LINEAR_MIPMAP_LINEAR"
seta image_ignoreHighQuality "0"
seta image_roundDown "0"
seta image_useCompression "0"
seta image_useNormalCompression "0"
seta image_anisotropy "16"
seta image_lodbias "0"
seta r_renderer "best"
seta r_multiSamples "8"
seta sys_lang "english"
seta s_alsa_pcm "hw:0,0"
seta com_allowConsole "1"
```
Please note that this will also set the game to use 8x anti-aliasing and restore the drop down console to how it worked in all of the previous Quake games. Similar to the Linux port of Doom 3 the Linux version of Quake 4 also does not support Creative EAX ADVANCED HD audio technology. Unlike Doom 3 though Quake 4 does seem to also feature an alternate method for surround sound, and widescreen support was thankfully patched into the game soon after its release.
### Playing the game
[![][12]][13] [![][14]][15]
Over the years Quake 4 has gained something of a reputation as the black sheep of the Quake family, with many people complaining that the game's vehicle sections, squad mechanics, and general aesthetic made it feel too close to contemporary military shooters of the time. In the game's heart of hearts though it really does feel like a concerted sequel to Quake II, with some of developer Raven Software's own Star Trek: Voyager - Elite Force title thrown in for good measure.
To me at least Quake 4 does stand as being one of the "Last of the Romans" in terms of being a first person shooter that embraced classic design ideals at a time when similar titles were not getting the support of major publishers. Most of the game still features the player moving between levels featuring fixed enemy placements, a wide variety of available weapons, traditional health packs, and an array of enemies each sporting unique attributes and skills.
Quake 4 also offers a well made campaign that I found myself going back to on a higher skill level not long after I had already finished my first try at the game. Certain aspects like the vehicle sections do indeed drag the game down a bit, and the multiplayer aspect pails in comparison to its predecessor Quake III Arena, but overall I am quite pleased with what Raven Software was able to accomplish with the Doom 3 engine, especially when so few others tried.
### Final thoughts
If anyone ever needed a reason to be reminded of the value of video game source code releases, this is it. Most of the problems I encountered could have been easily sidestepped if Quake 4 source ports were available, but with the likes of John Carmack and Timothee Besset gone from id Software and the current climate at ZeniMax not looking too promising, it is doubtful that any such creations will ever materialize. Doom 3 source ports look to be the end of the road.
Instead we are stuck using this cranky 32 bit binary with an obstructive CD Key check and a graphics system that freaks out at the sight of any modern video card sporting more than 512 MB of VRAM. The game itself has aged well, with graphics that still look great and dynamic lighting that is better than what is included with many modern titles. It is just a shame that it is now such a pain to get running, not just on Linux, but on any platform.
--------------------------------------------------------------------------------
via: https://www.gamingonlinux.com/articles/playing-quake-4-on-linux-in-2018.11017
作者：[Hamish][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.gamingonlinux.com/profiles/6
[1]:https://www.gamingonlinux.com/articles/playing-doom-3-on-linux-in-2017.10561
[2]:https://www.gamingonlinux.com/uploads/articles/article_images/thumbs/20458196191515697921gol6.jpg
[3]:https://www.gamingonlinux.com/uploads/articles/article_images/20458196191515697921gol6.jpg
[4]:https://www.gamingonlinux.com/uploads/articles/article_images/thumbs/9405540721515697921gol6.jpg
[5]:https://www.gamingonlinux.com/uploads/articles/article_images/9405540721515697921gol6.jpg
[6]:http://zerowing.idsoftware.com/linux/quake4/Quake4FrontPage/
[7]:https://www.quaddicted.com/files/idgames2/idstuff/quake4/linux/
[8]:https://www.quaddicted.com/
[9]:http://store.steampowered.com/app/2210/Quake_IV/
[10]:https://www.gog.com/game/quake_4
[11]:https://www.gog.com/forum/quake_series/quake_4_on_linux_no_cd_key/post31
[12]:https://www.gamingonlinux.com/uploads/articles/article_images/thumbs/5043571471515951537gol6.jpg
[13]:https://www.gamingonlinux.com/uploads/articles/article_images/5043571471515951537gol6.jpg
[14]:https://www.gamingonlinux.com/uploads/articles/article_images/thumbs/6922853731515697921gol6.jpg
[15]:https://www.gamingonlinux.com/uploads/articles/article_images/6922853731515697921gol6.jpg

77
sources/tech/20180114 What a GNU C Compiler Bug looks like.md Normal file
View File

@ -0,0 +1,77 @@
What a GNU C Compiler Bug looks like
======
Back in December a Linux Mint user sent a [strange bug report][1] to the darktable mailing list. Apparently the GNU C Compiler (GCC) on his system exited with the following error message, breaking the build process:
```
cc1: error: unrecognized command line option '-Wno-format-truncation' [-Werror]
cc1: all warnings being treated as errors
src/iop/CMakeFiles/colortransfer.dir/build.make:67: recipe for target 'src/iop/CMakeFiles/colortransfer.dir/introspection_colortransfer.c.o' failed make[2]: 0_sync_master.sh 1_add_new_article_manual.sh 1_add_new_article_newspaper.sh 2_start_translating.sh 3_continue_the_work.sh 4_finish.sh 5_pause.sh base.sh env format.test lctt.cfg parse_url_by_manual.sh parse_url_by_newspaper.py parse_url_by_newspaper.sh README.org reformat.sh [src/iop/CMakeFiles/colortransfer.dir/introspection_colortransfer.c.o] Error 1 CMakeFiles/Makefile2:6323: recipe for target 'src/iop/CMakeFiles/colortransfer.dir/all' failed
make[1]: 0_sync_master.sh 1_add_new_article_manual.sh 1_add_new_article_newspaper.sh 2_start_translating.sh 3_continue_the_work.sh 4_finish.sh 5_pause.sh base.sh env format.test lctt.cfg parse_url_by_manual.sh parse_url_by_newspaper.py parse_url_by_newspaper.sh README.org reformat.sh [src/iop/CMakeFiles/colortransfer.dir/all] Error 2
```
`-Wno-format-truncation` is a rather new GCC feature which instructs the compiler to issue a warning if it can already deduce at compile time that calls to formatted I/O functions like `snprintf()` or `vsnprintf()` might result in truncated output.
That's definitely neat, but Linux Mint 18.3 (just like Ubuntu 16.04 LTS) uses GCC 5.4.0, which doesn't support this feature. And darktable relies on a chain of CMake macros to make sure it doesn't use any flags the compiler doesn't know about:
```
CHECK_COMPILER_FLAG_AND_ENABLE_IT(-Wno-format-truncation)
```
So why did this even happen? I logged into one of my Ubuntu 16.04 installations and tried to reproduce the problem. Which wasn't hard, I just had to check out the git tree in question and build it. Boom, same error.
### The solution
It turns out that while `-Wformat-truncation` isn't a valid option for GCC 5.4.0 (it's not documented), this version silently accepts the negation under some circumstances (!):
```
sturmflut@hogsmeade:/tmp$ gcc -Wformat-truncation -o test test.c
gcc: error: unrecognized command line option '-Wformat-truncation'
sturmflut@hogsmeade:/tmp$ gcc -Wno-format-truncation -o test test.c
sturmflut@hogsmeade:/tmp$
```
(test.c just contains an empty main() method).
Because darktable uses `CHECK_COMPILER_FLAG_AND_ENABLE_IT(-Wno-format-truncation)`, it is fooled into thinking this compiler version actually supports `-Wno-format-truncation` at all times. The simple test case used by the CMake macro doesn't fail, but the compiler later decides to no longer silently accept the invalid command line option for some reason.
One of the cases which triggered this was when the source file under compilation had already generated some other warnings before. If I forced a serialized build using `make -j1` on a clean darktable checkout on this machine, `./src/iop/colortransfer.c` actually was the first file which caused any
compiler warnings at all, so this is why the process failed exactly there.
The minimum test case to trigger this behavior in GCC 5.4.0 is a C file with a `main()` function with a parameter which has the wrong type, like this one:
```
int main(int argc, int argv)
{
}
```
Then add `-Wall` to make sure the compiler will treat this as a warning, and it fails:
```
sturmflut@hogsmeade:/tmp$ gcc -Wall -Wno-format-truncation -o test test.c
test.c:1:5: warning: second argument of 'main' should be 'char **' [-Wmain]
int main(int argc, int argv)
^
cc1: warning: unrecognized command line option '-Wno-format-truncation'
```
If you omit `-Wall`, the compiler will not generate the first warning and also not complain about `-Wno-format-truncation`.
I've never run into this before, but I guess Ubuntu 16.04 is going to stay with us for a while since it is the current LTS release until May 2018, and even after that it will still be supported until 2021. So this buggy GCC version will most likely also stay alive for quite a while. Which is why the check for this flag has been removed from the
--------------------------------------------------------------------------------
via: http://www.lieberbiber.de/2018/01/14/what-a-gnu-compiler-bug-looks-like/
作者：[sturmflut][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) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:http://www.lieberbiber.de/author/sturmflut/
[1]:https://www.mail-archive.com/darktable-dev@lists.darktable.org/msg02760.html

57
sources/tech/20171019 More ways to examine network connections on Linux.md → translated/tech/20171019 More ways to examine network connections on Linux.md
View File

@ -1,13 +1,12 @@
translating by kimii
More ways to examine network connections on Linux
检查 linux 上网络连接的更多方法
======
The ifconfig and netstat commands are incredibly useful, but there are many other commands that can help you see what's up with you network on Linux systems. Today's post explores some very handy commands for examining network connections.
ifconfig 和 netstat 命令当然非常有用，但还有很多其他命令能帮你查看 linux 系统上的网络状况。本文探索了一些检查网络连接的非常简便的命令。
### ip command
### ip 命令
The **ip** command shows a lot of the same kind of information that you'll get when you use **ifconfig**. Some of the information is in a different format - e.g., "192.168.0.6/24" instead of "inet addr:192.168.0.6 Bcast:192.168.0.255" and ifconfig is better for packet counts, but the ip command has many useful options.
**ip** 命令显示了许多与你使用 **ifconfig** 命令时的一样信息。其中一些信息以不同的格式呈现，比如使用“192.168.0.6/24”，而不是“inet addr:192.168.0.6 Bcast:192.168.0.255”，尽管 ifconfig 更适合数据包计数，但 ip 命令有许多有用的选项。
First, here's the **ip a** command listing information on all network interfaces.
首先，这里是 **ip a** 命令列出的所有网络接口的信息。
```
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
@ -25,7 +24,7 @@ $ ip a
```
If you want only to see a simple list of network interfaces, you can limit its output with **grep**.
如果你只想看到简单的网络接口列表，你可以用 **grep** 限制它的输出。
```
$ ip a | grep inet
inet 127.0.0.1/8 scope host lo
@ -35,7 +34,7 @@ $ ip a | grep inet
```
You can get a glimpse of your default route using a command like this:
使用如下面的命令，你可以看到你的默认路由：
```
$ ip route show
default via 192.168.0.1 dev eth0
@ -43,18 +42,18 @@ default via 192.168.0.1 dev eth0
```
In this output, you can see that the default gateway is 192.168.0.1 through eth0 and that the local network is the fairly standard 192.168.0.0/24.
在这个输出中，你可以看到通过 eth0 的默认网关是 192.168.0.1，并且本地网络是相当标准的 192.168.0.0/24。
You can also use the **ip** command to bring network interfaces up and shut them down.
你也可以使用 **ip** 命令来启用和禁用网络接口。
```
$ sudo ip link set eth1 up
$ sudo ip link set eth1 down
```
### ethtool command
### ethtool 命令
Another very useful tool for examining networks is **ethtool**. This command provides a lot of descriptive data on network interfaces.
另一个检查网络非常有用的工具是 **ethtool**。这个命令提供了网络接口上的许多描述性的数据。
```
$ ethtool eth0
Settings for eth0:
@ -83,7 +82,7 @@ Cannot get wake-on-lan settings: Operation not permitted
```
You can also use the **ethtool** command to examine ethernet driver settings.
你也可以使用 **ethtool** 命令来检查以太网驱动设置。
```
$ ethtool -i eth0
driver: e1000e
@ -99,7 +98,7 @@ supports-priv-flags: no
```
The autonegotiation details can be displayed with a command like this:
自动协商的详细信息可以用这样的命令来显示：
```
$ ethtool -a eth0
Pause parameters for eth0:
@ -109,9 +108,10 @@ TX: on
```
### traceroute command
### traceroute 命令
The **traceroute** command displays routing pathways. It works by using the TTL (time to live) field in the packet header in a series of packets to capture the path that packets take and how long they take to get from one hop to the next. Traceroute's output helps to gauge the health of network connections, since some routes might take much longer to reach the eventual destination.
**traceroute** 命令显示路由路径。它通过在一系列数据包中设置数据包头的TTL（生存时间）字段来捕获数据包所经过的路径，以及数据包从一跳到下一跳需要的时间。Traceroute 的输出有助于评估网络连接的健康状况，因为某些路由可能需要花费更长的时间才能到达最终的目的地。
```
$ sudo traceroute world.std.com
traceroute to world.std.com (192.74.137.5), 30 hops max, 60 byte packets
@ -133,13 +133,13 @@ traceroute to world.std.com (192.74.137.5), 30 hops max, 60 byte packets
```
### tcptraceroute command
### tcptraceroute 命令
The **tcptraceroute** command does basically the same thing as traceroute except that it is able to bypass the most common firewall filters. As the command's man page explains, tcptraceroute sends out TCP SYN packets instead of UDP or ICMP ECHO packets, thus making it less susceptible to being blocked.
**tcptraceroute** 命令与 traceroute 基本上是一样的，只是它能够绕过最常见的防火墙的过滤。正如该命令的手册页所述，tcptraceroute 发送 TCP SYN 数据包而不是 UDP 或 ICMP ECHO 数据包，所以其不易被阻塞。
### tcpdump command
### tcpdump 命令
The **tcpdump** command allows you to capture network packets for later analysis. With the -D option, it lists available interfaces.
**tcpdump** 命令允许你捕获网络数据包来进一步分析。使用 -D 选项列出可用的网络接口。
```
$ tcpdump -D
1.eth0 [Up, Running]
@ -157,7 +157,7 @@ $ tcpdump -D
```
The -v (verbose) option controls how much detail you will see -- more v's, more details, but more than three v's doesn't add anything more.
-v（verbose）选项控制你看到的细节程度--越多的 v,越详细，但超过 3 个 v 不会有更多意义。
```
$ sudo tcpdump -vv host 192.168.0.32
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
@ -172,9 +172,10 @@ tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 byt
```
Expect to see a _lot_ of output when you run commands like this one.
当你运行像这样的命令时，会看到非常多的输出。
这个命令捕获来自特定主机和 eth0 上的 11 个数据包。-w 选项标识保存捕获包的文件。在这个示例命令中，我们只要求捕获 11 个数据包。
This command captures 11 packets from a specific host and over eth0. The -w option identifies the file that will contain the capture packets. In this example command, we've only asked to capture 11 packets.
```
$ sudo tcpdump -c 11 -i eth0 src 192.168.0.32 -w packets.pcap
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
@ -184,9 +185,10 @@ tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 byt
```
### arp command
### arp 命令
arp 命令将 IPv4 地址映射到硬件地址。它所提供的信息也可以在一定程度上用于识别系统，因为网络适配器可以告诉你使用它们的系统的一些信息。下面的第二个MAC 地址，从 f8：8e：85 开始，很容易被识别为 Comtrend 路由器。
The arp command maps IPv4 addresses to hardware addresses. The information provided can also be used to identify the systems to some extent, since the network adaptors in use can tell you something about the systems using them. The second MAC address below, starting with f8:8e:85, is easily identified as a Comtrend router.
```
$ arp -a
? (192.168.0.12) at b0:c0:90:3f:10:15 [ether] on eth0
@ -194,15 +196,14 @@ $ arp -a
```
The first line above shows the MAC address for the network adaptor on the system itself. This network adaptor appears to have been manufactured by Chicony Electronics in Taiwan. You can look up MAC address associations fairly easily on the web with tools such as this one from Wireshark -- https://www.wireshark.org/tools/oui-lookup.html
上面的第一行显示了系统本身的网络适配器的 MAC 地址。该网络适配器似乎已由台湾 Chicony 电子公司制造。你可以很容易地在网上查找 MAC 地址关联，例如来自 Wireshark 的这个工具 -- https://www.wireshark.org/tools/oui-lookup.html
--------------------------------------------------------------------------------
via: https://www.networkworld.com/article/3233306/linux/more-ways-to-examine-network-connections-on-linux.html
作者：[Sandra Henry-Stocker][a]
译者：[译者ID](https://github.com/译者ID)
译者：[kimii](https://github.com/kimii)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出

170
translated/tech/20171207 How To Find Files Based On their Permissions.md Normal file
View File

@ -0,0 +1,170 @@
根据权限查找文件
======
在 Linux 中查找文件并不是什么大问题。市面上也有很多可靠的免费开源可视化的查询工具。但对我而言，查询文件，用命令行的方式会更快更简单。我们已经知道 [ 如何根据访问、修改文件时间寻找或整理文件 ][1]。今天，在基于 Unix 的操作系统中，我们将见识如何通过权限查询文件。
本段教程中，我将创建三个文件名为 **file1**，**file2** 和 **file3** 分别赋予 **777**，**766** 和 **655** 文件权限，并分别置于名为 **ostechnix** 的文件夹中。
```
mkdir ostechnix && cd ostechnix/
```
```
install -b -m 777 /dev/null file1
```
```
install -b -m 766 /dev/null file2
```
```
install -b -m 655 /dev/null file3
```
![][3]
现在，让我们通过权限来查询一下文件。
### 根据权限查询文件
根据权限查询文件最具代表性的语法：
```
find -perm mode
```
MODE 可以是代表权限的八进制数字（777，666…）也可以是权限符号（u=x，a=r+x）。
在深入之前，我们就以下三点详细说明 MODE 参数。
1. 如果我们不指定任何参数前缀，它将会寻找 **具体** 权限的文件。
2. 如果我们使用 **“-”** 参数前缀， 寻找到的文件至少拥有 mode 所述的权限，而不是具体的权限（大于或等于此权限的文件都会被查找出来）。
3. 如果我们使用 **“/”** 参数前缀，那么所有者、组或者其他人任意一个应当享有此文件的权限。
为了让你更好的理解，让我举些例子。
首先，我们将要看到基于数字权限查询文件。
### 基于数字（八进制）权限查询文件
让我们运行下列命令：
```
find -perm 777
```
这条命令将会查询到当前目录权限为 **确切为 777** 权限的文件。
![1][4]
当你看见屏幕输出行时，file1 是唯一一个拥有 **确切为 777 权限** 的文件。
现在，让我们使用 “-” 参数前缀，看看会发生什么。
```
find -perm -766
```
![][5]
如你所见，命令行上显示两个文件。我们给 file2 设置了 766 权限，但是命令行显示两个文件，什么鬼？因为，我们设置了 “-” 参数前缀。它意味着这条命令将在所有文件中查询文件所有者的 读/写/执行 权限，文件用户组的 读/写权限和其他用户的 读/写 全西安。本例中，file1 和 file2 都符合要求。换句话说，文件并不一样要求时确切的 766 权限。它将会显示任何属于（高于）此权限的文件 。
然后，让我们使用 “/” 参数前置，看看会发生什么。
```
find -perm /222
```
![][6]
上述命令将会查询所有者、用户组或其他拥有写权限的文件。这里有另外一个例子
```
find -perm /220
```
这条命令会查询所有者或用户组中拥有写权限的文件。这意味着 **所有者和用户组** 中匹配 **不全拥有写权限**。
如果你使用 “-” 前缀运行相同的命令，你只会看到所有者和用户组都拥有写权限的文件。
```
find -perm -220
```
下面的截图会告诉你这两个参数前缀的不同。
![][7]
如我之前说过的一样，我们可以使用符号表示文件权限。
请阅读：
### 基于符号的文件权限查询文件
在下面的例子中，我们使用例如 **u**（所有者），**g**（用户组） 和 **o**（其他） 的符号表示法。我们也可以使用字母 **a** 代表上述三种类型。我们可以通过特指的 **r** (读), **w** (写), **x** (执行) 分别代表它们的权限。
例如，寻找用户组中拥有 **写** 权限的文件，执行：
```
find -perm -g=w
```
![][8]
上面的例子中，file1 和 file2 都拥有 **写** 权限。请注意，你可以等效使用 “=”或“+”两种符号标识。例如，下列两行相同效果的代码。
```
find -perm -g=w
find -perm -g+w
```
查询文件所有者中拥有写权限的文件，执行：
```
find -perm -u=w
```
查询所有用户中拥有写权限的文件，执行：
```
find -perm -a=w
```
查询 **所有者** 和 **用户组** 中同时拥有写权限的文件，执行：
```
find -perm -g+w,u+w
```
上述命令等效与“find -perm -220”。
查询 **所有者** 或 **用户组** 中拥有写权限的文件，执行：
```
find -perm /u+w,g+w
```
或者,
```
find -perm /u=w,g=w
```
上述命令等效于 “find -perm /220”。
更多详情，参照 man 手册。
```
man find
```
了解更多简化案例或其他 Linux 命令，查看[**man 手册**][9]。
然后，这就是所有的内容。希望这个教程有用。更多干货，敬请关注。
干杯！
--------------------------------------------------------------------------------
via: https://www.ostechnix.com/find-files-based-permissions/
作者：[][a]
译者：[CYLeft](https://github.com/CYLeft)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.ostechnix.com
[1]:https://www.ostechnix.com/find-sort-files-based-access-modification-date-time-linux/
[2]:data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7/
[3]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-1-1.png
[4]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-2.png
[5]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-3.png
[6]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-6.png
[7]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-7.png
[8]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-8.png
[9]:https://www.ostechnix.com/3-good-alternatives-man-pages-every-linux-user-know/

88
translated/tech/20180104 How to Change Your Linux Console Fonts.md Normal file
View File

@ -0,0 +1,88 @@
如何更改 Linux 控制台上的字体
======
![](https：//www.linux.com/sites/lcom/files/styles/rendered_file/public/font-size_0.png？itok=d97vmyYa)
我尝试尽可能的保持心灵祥和，然而总有一些事情让我意难平，比如控制台字体太小了。记住我的话，朋友，有一天你的眼睛会退化，无法再看清你编码时用的那些细小字体，到那时你就后悔莫及了。
幸好，Linux 死忠们，你可以更改控制台的字体。按照 Linux 一贯的尿性，不断变化的 Linux 环境使得这个问题变得不太简单明了，而 Linux 上也没有字体管理这么个东西，这使得我们很容易就被搞晕了。本文，我将会向你展示，我找到的更改字体的最简方法。
### Linux 控制台是个什么鬼？
首先让我们来澄清一下我们说的到底是个什么东西。当我提到 Linux 控制台，我指的是 TTY1-6，即你从图形环境用 `Ctrl-Alt-F1` 到 `F6` 切换到的虚拟终端。按下 `Ctrl+Alt+F7` 会切回图形环境。(不过这些热键已经不再通用，你的 Linux 发行版可能有不同的键映射。你的 TTY 的数量也可能不同，你图形环境会话也可能不在 `F7`。比如，Fedora 的默认图形会话是 `F2`，它只有一个额外的终端在 `F1`。) 我觉得能同时拥有 X 会话和终端绘画实在是太酷了。
Linux 控制台是内核的一部分，而且并不运行在 X 会话中。它和你在没有图形环境的无头服务器中用的控制台是一样的。我称呼在图形会话中的 X 终端为终端，而将控制台和 X 终端统称为终端模拟器。
但这还没完。Linux 终端从早期的 ANSI 时代开始已经经历了长久的发展，多亏了 Linux framebuffer，它现在支持 Unicode 并且对图形也有了有限的一些支持。而且出现了很多在控制台下运行的多媒体应用，这些我们在以后的文章中会提到。
### 控制台截屏
获取控制台截屏的最简单方法是让控制台跑在虚拟机内部。然后你可以在宿主系统上使用中意的截屏软件来抓取。不过借助 [fbcat][1] 和 [fbgrab][2] 你也可以直接在控制台上截屏。`fbcat` 会创建一个可移植的像素映射格式 (PPM) 图像; 这是一个高度可移植的未压缩图像格式，可以在所有的操作系统上读取，当然你也可以把它转换成任何喜欢的其他格式。`fbgrab` 则是 `fbcat` 的一个封装脚本，用来生成一个 PNG 文件。不同的人写过多个版本的 `fbgrab`。每个版本的选项都有限而且只能创建截取全屏。
`fbcat` 的执行需要 root 权限，而且它的输出需要重定向到文件中。你无需指定文件扩展名，只需要输入文件名就行了：
```
$ sudo fbcat > Pictures/myfile
```
在 GIMP 中裁剪后，就得到了图 1。
![](https：//www.linux.com/sites/lcom/files/styles/rendered_file/public/fig-1_10.png？itok=bHOxrZk9)
Figure 1：View after cropping。
如果能在左边空白处有一点填充就好了，如果有读者知道如何实现请在留言框中告诉我。
`fbgrab` 还有一些选项，你可以通过 `man fbgrab` 来查看，这些选项包括对另一个控制台进行截屏，以及延时截屏。在下面的例子中可以看到，`fbgrab` 截屏跟 `fbcat` 截屏类似，只是你无需明确进行输出重定性了：
```
$ sudo fbgrab Pictures/myOtherfile
```
### 查找字体
就我所知，除了查看字体存储目录 `/usr/share/consolefonts/`(Debian/etc。)，`/lib/kbd/consolefonts/` (Fedora)，`/usr/share/kbd/consolefonts` (openSUSE)，外没有其他方法可以列出已安装的字体了。
### 更改字体
可读字体不是什么新概念。我们应该尊重以前的经验！可读性是很重要的。可配置性也很重要，然而现如今却不怎么看重了。
在 Debian/Ubuntu/ 等系统上，可以运行 `sudo dpkg-reconfigure console-setup` 来设置控制台字体，然后在控制台运行 `setupcon` 命令来让变更生效。`setupcon` 属于 `console-setup` 软件包中的一部分。若你的 Linux 发行版中不包含该工具，可以在 [openSUSE][3] 中下载到它。
你也可以直接编辑 `/etc/default/console-setup` 文件。下面这个例子中设置字体为 32 点大小的 Terminus Bold 字体，这是我的最爱，并且严格限制控制台宽度为 80 列。
```
ACTIVE_CONSOLES="/dev/tty[1-6]"
CHARMAP="UTF-8"
CODESET="guess"
FONTFACE="TerminusBold"
FONTSIZE="16x32"
SCREEN_WIDTH="80"
```
这里的 FONTFACE 和 FONTSIZE 的值来自于字体的文件名，`TerminusBold32x16.psf.gz`。是的，你需要反转 FONTSIZE 中值的顺序。计算机就是这么搞笑。然后再运行 `setupcon` 来让新配置生效。可以使用 `showconsolefont` 来查看当前所用字体的所有字符集。要查看完整的选项说明请参考 `man console-setup`。
### Systemd
Systemd 与 `console-setup` 不太一样，除了字体之外，你无需安装任何东西。你只需要编辑 `/etc/vconsole.conf` 然后重启就行了。我在 Fedora 和 openSUSE 系统中安装了一些额外的大型号的 Terminus 字体包，因为默认安装的字体最大只有 16 点而我想要的是 32 点。然后将 `/etc/vconsole.conf` 的内容修改为：
```
KEYMAP="us"
FONT="ter-v32b"
```
下周我们还将学习一些更加酷的控制台小技巧，以及一些在控制台上运行的多媒体应用。
--------------------------------------------------------------------------------
via: https://www.linux.com/learn/intro-to-linux/2018/1/how-change-your-linux-console-fonts
作者：[Carla Schroder][a]
译者：[lujun9972](https://github.com/lujun9972)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.linux.com/users/cschroder
[1]:http://jwilk.net/software/fbcat
[2]:https://github.com/jwilk/fbcat/blob/master/fbgrab
[3]:https://software.opensuse.org/package/console-setup

118
translated/tech/20180111 The Fold Command Tutorial With Examples For Beginners.md Normal file
View File

@ -0,0 +1,118 @@
Fold命令入门级示例教程
======
![](https://www.ostechnix.com/wp-content/uploads/2018/01/Fold-Command-2-720x340.png)
你有没有发现自己在某种情况下想要折叠或打破命令的输出用于适应特定的宽度？ 在运行虚拟机的时候，我遇到了几次这种的情况，特别是没有GUI的服务器。 以防万一，如果你想限制一个命令的输出为一个特定的宽度，现在看看这里！ **fold**命令在这里就能派的上用场了！ fold命令以适合指定的宽度调整输入文件中的每一行并将其打印到标准输出。
在这个简短的教程中，我们将看到fold命令的用法，带有实例哦。
### fold命令示例教程
fold命令是GNU coreutils包的一部分，所以我们不用为安装的事情烦恼。
fold命令的典型语法：
```
fold [OPTION]... [FILE]...
```
请允许我向您展示一些示例，以便您更好地了解fold命令。 我有一个名为linux.txt文件，内容是随机的。
Allow me to show you some examples, so you can get a better idea about fold command. I have a file named **linux.txt** with some random lines.
![][2]
要将上述文件中的每一行换行为默认宽度，请运行：
```
fold linux.txt
```
每行**80**列是默认的宽度。 这里是上述命令的输出：
![][3]
正如你在上面的输出中看到的，fold命令已经将输出限制为80个字符的宽度。
当然，我们可以指定您的首选宽度，例如50，如下所示：
```
fold -w50 linux.txt
```
Sample output would be:
![][4]
我们也可以将输出写入一个新的文件，如下所示：
```
fold -w50 linux.txt > linux1.txt
```
以上命令将把**linux.txt**的行宽度改为50个字符，并将输出写入到名为**linux1.txt**的新文件中。
让我们检查一下新文件的内容：
```
cat linux1.txt
```
![][5]
你有没有注意到前面的命令的输出？ 有些词在行之间被打破。 为了解决这个问题，我们可以使用-s标志来在空格处换行。
以下命令将给定文件中的每行调整为宽度“50”，并在空格处换到新行：
```
fold -w50 -s linux.txt
```
示例输出：
![][6]
看清楚了吗？ 现在，输出很清楚。 换到新行中的单词都是用空格隔开的，所在行单词的长度大于50的时候就会被调整到下一行。
在所有上面的例子中，我们用列来限制输出宽度。 但是，我们可以使用**-b**选项将输出的宽度强制为指定的字节数。 以下命令以20个字节中断输出。
```
fold -b20 linux.txt
```
Sample output:
![][7]
**另请阅读：**
+ [Unix命令入门级示例教程][8]
有关更多详细信息，请参阅man手册页。
```
man fold
```
而且，这些就是所有的内容了。 您现在知道如何使用fold命令以适应特定的宽度来限制命令的输出。 我希望这是有用的。 我们将每天发布更多有用的指南。 敬请关注！
干杯!
--------------------------------------------------------------------------------
via: https://www.ostechnix.com/fold-command-tutorial-examples-beginners/
作者：[SK][a]
译者：[Flowsnow](https://github.com/Flowsnow)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]:https://www.ostechnix.com/author/sk/
[1]:data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
[2]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-1.png
[3]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-2.png
[4]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-3-1.png
[5]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-4.png
[6]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-5-1.png
[7]:http://www.ostechnix.com/wp-content/uploads/2018/01/fold-command-6-1.png
[8]:https://www.ostechnix.com/uniq-command-tutorial-examples-beginners/