应该知道的LINUX技巧

朴灿烈づ我的快乐病毒、 2022-06-10 08:07 195阅读 0赞

http://coolshell.cn/articles/8883.html

这篇文章来源于Quroa的一个问答《[What are some time-saving tips that every Linux user should know?][What are some time-saving tips that every Linux user should know]》—— Linux用户有哪些应该知道的提高效率的技巧。我觉得挺好的，总结得比较好，把其转过来，并加了一些自己的理解。 首先，我想告诉大家，在Unix/Linux下，最有效率技巧的不是操作图形界面，而是命令行操作，因为命令行意味着自动化。如果你看过《[你可能不知道的Shell][Shell]》以及《[28个Unix/Linux的命令行神器][28_Unix_Linux]》你就会知道Linux有多强大，这个强大完全来自于命令行，于是，就算你不知道怎么去[做一个环保主义的程序员][Link 1]，至少他们可以让你少熬点夜，从而有利于你的身体健康和性生活。下面是一个有点长的列表，正如作者所说，你并不需要知道所有的这些东西，但是如果你还在很沉重地在使用Linux的话，这些东西都值得你看一看。 （注：如果你想知道下面涉及到的命令的更多的用法，你一定要man一点。对于一些命令，你可以需要先yum或apt-get来安装一下，如果有什么问题，别忘了Google。如果你要Baidu的话，我仅代表这个地球上所有的生物包括微生物甚至细菌病毒和小强BS你到宇宙毁灭）

#### 基础 ####

*  学习 [Bash][]。你可以man bash来看看bash的东西，并不复杂也并不长。你用别的shell也行，但是bash是很强大的并且也是系统默认的。（学习zsh或tsch只会让你在很多情况下受到限制）

*  学习 vim 。在Linux下，基本没有什么可与之竞争的编译辑器（就算你是一个Emacs或Eclipse的重度用户）。你可以看看《[简明vim攻略][vim]》和 《[Vim的冒险游戏][Vim]》以及《[给程序员的Vim速查卡][Vim 1]》还有《[把Vim变成一个编程的IDE][Vim_IDE]》等等。

*  了解 ssh。明白不需要口令的用户认证（通过ssh-agent, ssh-add），学会用ssh翻墙，用scp而不是ftp传文件，等等。你知道吗？scp 远端的时候，你可以按tab键来查看远端的目录和文件（当然，需要无口令的用户认证），这都是bash的功劳。

*  熟悉bash的作业管理，如： &, Ctrl-Z, Ctrl-C, jobs, fg, bg, kill, 等等。当然，你也要知道Ctrl+\\（SIGQUIT）和Ctrl+C （SIGINT）的区别。

*  简单的文件管理 ： ls 和 ls -l (你最好知道 “ls -l” 的每一列的意思), less, head, tail 和 tail -f, ln 和 ln -s (你知道明白hard link和soft link的不同和优缺点), chown, chmod, du (如果你想看看磁盘的大小 du -sk \*), df, mount。当然，原作者忘了find命令。

*  基础的网络管理： ip 或 ifconfig, dig。当然，原作者还忘了如netstat, ping, traceroute, 等

*  理解正则表达式，还有grep/egrep的各种选项。比如： -o, -A, 和 -B 这些选项是很值得了解的。

*  学习使用 apt-get 和 yum 来查找和安装软件（前者的经典分发包是Ubuntu，后者的经典分发包是Redhat），我还建议你试着从源码编译安装软件。

日常

*  在 bash 里，使用 Ctrl-R 而不是上下光标键来查找历史命令。

*  在 bash里，使用 Ctrl-W 来删除最后一个单词，使用 Ctrl-U 来删除一行。请man bash后查找Readline Key Bindings一节来看看bash的默认热键，比如：Alt-. 把上一次命令的最后一个参数打出来，而Alt-\* 则列出你可以输入的命令。

*  回到上一次的工作目录： cd – （回到home是 cd ~）

*  使用 xargs。这是一个很强大的命令。你可以使用-L来限定有多少个命令，也可以用-P来指定并行的进程数。如果你不知道你的命令会变成什么样，你可以使用xargs echo来看看会是什么样。当然， -I\{\} 也很好用。示例：

*  pstree -p 可以帮你显示进程树。（读过我的那篇《[一个fork的面试题][fork]》的人应该都不陌生）

*  使用 pgrep 和 pkill 来找到或是kill 某个名字的进程。 (-f 选项很有用).

*  了解可以发给进程的信号。例如：要挂起一个进程，使用 kill -STOP \[pid\]. 使用 man 7 signal 来查看各种信号，使用kill -l 来查看数字和信号的对应表

*  使用 nohup 或 disown 如果你要让某个进程运行在后台。

*  使用netstat -lntp来看看有侦听在网络某端口的进程。当然，也可以使用 lsof。

*  在bash的脚本中，你可以使用 set -x 来debug输出。使用 set -e 来当有错误发生的时候abort执行。考虑使用 set -o pipefail 来限制错误。还可以使用trap来截获信号（如截获ctrl+c）。

*  在bash 脚本中，subshells (写在圆括号里的) 是一个很方便的方式来组合一些命令。一个常用的例子是临时地到另一个目录中，例如：

*  在 bash 中，注意那里有很多的变量展开。如：检查一个变量是否存在: $\{name:?error message\}。如果一个bash的脚本需要一个参数，也许就是这样一个表达式 input\_file=$\{1:?usage: $0 input\_file\}。一个计算表达式： i=$(( (i + 1) % 5 ))。一个序列： \{1..10\}。 截断一个字符串： $\{var%suffix\} 和 $\{var\#prefix\}。 示例： if var=foo.pdf, then echo $\{var%.pdf\}.txt prints “foo.txt”.

*  通过 <(some command) 可以把某命令当成一个文件。示例：比较一个本地文件和远程文件 /etc/hosts： diff /etc/hosts <(ssh somehost cat /etc/hosts)

*  了解什么叫 “[here documents][]” ，就是诸如 cat <<EOF 这样的东西。

*  在 bash中，使用重定向到标准输出和标准错误。如： some-command >logfile 2>&1。另外，要确认某命令没有把某个打开了的文件句柄重定向给标准输入，最佳实践是加上 “</dev/null”，把/dev/null重定向到标准输入。

*  使用 man ascii 来查看 ASCII 表。

*  在远端的 ssh 会话里，使用 screen 或 dtach 来保存你的会话。（参看《[28个Unix/Linux的命令行神器][28_Unix_Linux]》）

*  要来debug Web，试试curl 和 curl -I 或是 wget 。我觉得debug Web的利器是firebug，curl和wget是用来抓网页的，呵呵。

*  把 HTML 转成文本： lynx -dump -stdin

*  如果你要处理XML，使用 xmlstarlet

*  对于 Amazon S3， s3cmd 是一个很方便的命令（还有点不成熟）

*  在 ssh中，知道怎么来使用ssh隧道。通过 -L or -D (还有-R) ，翻墙神器。

*  你还可以对你的ssh 做点优化。比如，.ssh/config 包含着一些配置：避免链接被丢弃，链接新的host时不需要确认，转发认证，以前使用压缩（如果你要使用scp传文件）：

> <table style="border-spacing:0px; width:649px; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important; table-layout:auto!important"> 
>  <tbody style="background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important"> 
>   <tr style="background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important"> 
>    <td style="padding:0px!important; border:0px!important; background:none!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important; color:rgb(175,175,175)!important"> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       1 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       2 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       3 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       4 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       5 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       6 
>     </div> </td> 
>    <td style="width:618px; padding:0px!important; border:0px!important; background:none!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important"> 
>     <div style="padding:0px!important; margin:0px!important; width:auto!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:relative!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-size:1em!important; direction:ltr!important"> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">TCPKeepAlive=</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">yes</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">ServerAliveInterval=15</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">ServerAliveCountMax=6</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">StrictHostKeyChecking=no</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">Compression=</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">yes</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">ForwardAgent=</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">yes</code> 
>      </div> 
>     </div> </td> 
>   </tr> 
>  </tbody> 
> </table>

*  如果你有输了个命令行，但是你改变注意了，但你又不想删除它，因为你要在历史命令中找到它，但你也不想执行它。那么，你可以按下 Alt-\# ，于是这个命令关就被加了一个\#字符，于是就被注释掉了。

数据处理

*  了解 sort 和 uniq 命令 (包括 uniq 的 -u 和 -d 选项).

*  了解用 cut, paste, 和 join 命令来操作文本文件。很多人忘了在cut前使用join。

*  如果你知道怎么用sort/uniq来做集合交集、并集、差集能很大地促进你的工作效率。假设有两个文本文件a和b已解被 uniq了，那么，用sort/uniq会是最快的方式，无论这两个文件有多大（sort不会被内存所限，你甚至可以使用-T选项，如果你的/tmp目录很小）

> <table style="border-spacing:0px; width:649px; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important; table-layout:auto!important"> 
>  <tbody style="background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important"> 
>   <tr style="background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important"> 
>    <td style="padding:0px!important; border:0px!important; background:none!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important; color:rgb(175,175,175)!important"> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       1 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       2 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       3 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       4 
>     </div> 
>     <div style="border-width:0px 3px 0px 0px!important; border-top-style:initial!important; border-right-style:solid!important; border-bottom-style:initial!important; border-left-style:initial!important; border-top-color:initial!important; border-right-color:rgb(108,226,108)!important; border-bottom-color:initial!important; border-left-color:initial!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 0.5em 0px 1em!important; position:static!important; right:auto!important; text-align:right!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>       5 
>     </div> </td> 
>    <td style="width:618px; padding:0px!important; border:0px!important; background:none!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; direction:ltr!important"> 
>     <div style="padding:0px!important; margin:0px!important; width:auto!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; outline:0px!important; overflow:visible!important; position:relative!important; right:auto!important; top:auto!important; vertical-align:baseline!important; font-size:1em!important; direction:ltr!important"> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">cat</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> a b | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">sort</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">uniq</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> &gt; c&nbsp;&nbsp; </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(0,130,0)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"># c is a union b 并集</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>        &nbsp; 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">cat</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> a b | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">sort</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">uniq</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> -d &gt; c&nbsp;&nbsp; </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(0,130,0)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"># c is a intersect b 交集</code> 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important">
>        &nbsp; 
>      </div> 
>      <div style="border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:20px!important; margin:0px!important; outline:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-size:1em!important; direction:ltr!important; white-space:pre!important"> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">cat</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> a b b | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">sort</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> | </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(255,20,147)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important">uniq</code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"> -u &gt; c&nbsp;&nbsp; </code> 
>       <code style="font-family:Monaco,Consolas,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,Courier,monospace!important; font-size:1em!important; padding:0px!important; color:rgb(0,130,0)!important; background:none!important; border:0px!important; bottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.1em!important; margin:0px!important; outline:0px!important; overflow:visible!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; direction:ltr!important; display:inline!important"># c is set difference a - b 差集</code> 
>      </div> 
>     </div> </td> 
>   </tr> 
>  </tbody> 
> </table>

*  了解和字符集相关的命令行工具，包括排序和性能。很多的Linux安装程序都会设置LANG 或是其它和字符集相关的环境变量。这些东西可能会让一些命令（如：sort）的执行性能慢N多倍（注：就算是你用UTF-8编码文本文件，你也可以很安全地使用ASCII来对其排序）。如果你想Disable那个i18n 并使用传统的基于byte的排序方法，那就设置export LC\_ALL=C （实际上，你可以把其放在 .bashrc）。如果这设置这个变量，你的sort命令很有可能会是错的。

*  了解 awk 和 sed，并用他们来做一些简单的数据修改操作。例如：求第三列的数字之和： awk ‘\{ x += $3 \} END \{ print x \}’。这可能会比Python快3倍，并比Python的代码少三倍。

*  使用 shuf 来打乱一个文件中的行或是选择文件中一个随机的行。

*  了解sort命令的选项。了解key是什么（-t和-k）。具体说来，你可以使用-k1,1来对第一列排序，-k1来对全行排序。

*  Stable sort (sort -s) 会很有用。例如：如果你要想对两例排序，先是以第二列，然后再以第一列，那么你可以这样： sort -k1,1 | sort -s -k2,2

*  我们知道，在bash命令行下，Tab键是用来做目录文件自动完成的事的。但是如果你想输入一个Tab字符（比如：你想在sort -t选项后输入<tab>字符），你可以先按Ctrl-V，然后再按Tab键，就可以输入<tab>字符了。当然，你也可以使用$’\\t’。

*  如果你想查看二进制文件，你可以使用hd命令（在CentOS下是hexdump命令），如果你想编译二进制文件，你可以使用bvi命令（[http://bvi.sourceforge.net/][http_bvi.sourceforge.net] 墙）

*  另外，对于二进制文件，你可以使用strings（配合grep等）来查看二进制中的文本。

*  对于文本文件转码，你可以试一下 iconv。或是试试更强的 uconv 命令（这个命令支持更高级的Unicode编码）

*  如果你要分隔一个大文件，你可以使用split命令（split by size）和csplit命令（split by a pattern）。

系统调试

*  如果你想知道磁盘、CPU、或网络状态，你可以使用 iostat, netstat, top (或更好的 htop), 还有 dstat 命令。你可以很快地知道你的系统发生了什么事。关于这方面的命令，还有iftop, iotop等（参看《[28个Unix/Linux的命令行神器][28_Unix_Linux]》）

*  要了解内存的状态，你可以使用free和vmstat命令。具体来说，你需要注意 “cached” 的值，这个值是Linux内核占用的内存。还有free的值。

*  Java 系统监控有一个小的技巧是，你可以使用kill -3 <pid> 发一个SIGQUIT的信号给JVM，可以把堆栈信息（包括垃圾回收的信息）dump到stderr/logs。

*  使用 mtr 会比使用 traceroute 要更容易定位一个网络问题。

*  如果你要找到哪个socket或进程在使用网络带宽，你可以使用 iftop 或 nethogs。

*  Apache的一个叫 ab 的工具是一个很有用的，用quick-and-dirty的方式来测试网站服务器的性能负载的工作。如果你需要更为复杂的测试，你可以试试 siege。

*  如果你要抓网络包的话，试试 wireshark 或 tshark。

*  了解 strace 和 ltrace。这两个命令可以让你查看进程的系统调用，这有助于你分析进程的hang在哪了，怎么crash和failed的。你还可以用其来做性能profile，使用 -c 选项，你可以使用-p选项来attach上任意一个进程。

*  了解用ldd命令来检查相关的动态链接库。注意：[ldd的安全问题][ldd]

*  使用gdb来调试一个正在运行的进程或分析core dump文件。参看我写的《[GDB中应该知道的几个调试方法][GDB]》

*  学会到 /proc 目录中查看信息。这是一个Linux内核运行时记录的整个操作系统的运行统计和信息，比如： /proc/cpuinfo, /proc/xxx/cwd, /proc/xxx/exe, /proc/xxx/fd/, /proc/xxx/smaps.

*  如果你调试某个东西为什么出错时，sar命令会有用。它可以让你看看 CPU, 内存, 网络, 等的统计信息。

*  使用 dmesg 来查看一些硬件或驱动程序的信息或问题。

作者最后加了一个免责声明：Disclaimer: Just because you can do something in bash, doesn’t necessarily mean you should. ;) （全文完）

[What are some time-saving tips that every Linux user should know]: http://www.quora.com/Linux/What-are-some-time-saving-tips-that-every-Linux-user-should-know#
[Shell]: http://coolshell.cn/articles/8619.html
[28_Unix_Linux]: http://coolshell.cn/articles/7829.html
[Link 1]: http://coolshell.cn/articles/7186.html
[Bash]: http://www.quora.com/Bash-shell
[vim]: http://coolshell.cn/articles/5426.html
[Vim]: http://coolshell.cn/articles/7166.html
[Vim 1]: http://coolshell.cn/articles/5479.html
[Vim_IDE]: http://coolshell.cn/articles/894.html
[fork]: http://coolshell.cn/articles/7965.html
[here documents]: http://zh.wikipedia.org/wiki/Here%E6%96%87%E6%A1%A3
[http_bvi.sourceforge.net]: http://bvi.sourceforge.net/
[ldd]: http://coolshell.cn/articles/1626.html
[GDB]: http://coolshell.cn/articles/3643.html