這10個(gè) Linux 命令，讓你的操作更有效率

來源：老九課堂

01 pgrep

pgrep名字前有個(gè)p，我們可以猜到這和進(jìn)程相關(guān)，又是grep，當(dāng)然這是進(jìn)程相關(guān)的grep命令。不過，這個(gè)命令主要是用來列舉進(jìn)程ID的。如：

$?pgrep?-u?hchen2244122444

這個(gè)命令相當(dāng)于：

ps?-ef?|?egrep?'^hchen'?|?awk?'{print?$2}'

02 pstree

這個(gè)命令可以以樹形的方式列出進(jìn)程。如下所示：

[hchen@RHELSVR5?~]$?pstree
init-+-acpid
?????|-auditd-+-python
?????|????????`-{auditd}
?????|-automount---4*[{automount}]
?????|-backup.sh---sleep
?????|-dbus-daemon
?????|-events/0
?????|-events/1
?????|-hald---hald-runner---hald-addon-acpi
?????|-httpd---10*[httpd]
?????|-irqbalance
?????|-khelper
?????|-klogd
?????|-ksoftirqd/0
?????|-ksoftirqd/1
?????|-kthread-+-aio/0
?????|?????????|-aio/1
?????|?????????|-ata/0
?????|?????????|-ata/1
?????|?????????|-ata_aux
?????|?????????|-cqueue/0
?????|?????????|-cqueue/1
?????|?????????|-kacpid
?????|?????????|-kauditd
?????|?????????|-kblockd/0
?????|?????????|-kblockd/1
?????|?????????|-kedac
?????|?????????|-khubd
?????|?????????|-6*[kjournald]
?????|?????????|-kmirrord
?????|?????????|-kpsmoused
?????|?????????|-kseriod
?????|?????????|-kswapd0
?????|?????????|-2*[pdflush]
?????|?????????|-scsi_eh_0
?????|?????????|-scsi_eh_1
?????|?????????|-xenbus
?????|?????????`-xenwatch
?????|-migration/0
?????|-migration/1
?????|-6*[mingetty]
?????|-3*[multilog]
?????|-mysqld_safe---mysqld---9*[{mysqld}]
?????|-smartd
?????|-sshd---sshd---sshd---bash---pstree
?????|-svscanboot---svscan-+-3*[supervise---run]
?????|?????????????????????|-supervise---qmail-send-+-qmail-clean
?????|?????????????????????|????????????????????????|-qmail-lspawn
?????|?????????????????????|????????????????????????`-qmail-rspawn
?????|?????????????????????`-2*[supervise---tcpserver]
?????|-syslogd
?????|-udevd
?????|-watchdog/0
?????|-watchdog/1
?????-xinetd

03 bc

這個(gè)命令主要是做一個(gè)精度比較高的數(shù)學(xué)運(yùn)算的。比如開平方根等。下面是一個(gè)我們利用bc命令寫的一個(gè)腳本（文件名：sqrt）

#!/bin/bash
if?[?$#?-ne?1?]
then
echo?'Usage:?sqrt?number'
exit?1else
????echo?-e?"sqrt($1)\nquit\n"?|?bc?-q?-i
fi

于是，我們可以這樣使用這個(gè)腳本進(jìn)行平方根運(yùn)算：

[hchen@RHELSVR5]$?./sqrt?36
6
[hchen@RHELSVR5]$?./sqrt?2.0000
1.4142
[hchen@RHELSVR5]$?./sqrt?10.0000
3.1622

04 split

[hchen@RHELSVR5?applebak]#?ls?-l?largefile.tar.gz
-rw-r--r--?1?hchen?hchen?436774774?04-17?02:00?largefile.tar.gz
[hchen@RHELSVR5?applebak]#?split?-b?50m?largefile.tar.gz?LF_
[hchen@RHELSVR5]#?ls?-l?LF_*-rw-r--r--?1?hchen?hchen?52428800?05-10?18:34?LF_aa
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:34?LF_ab
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:34?LF_ac
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:34?LF_ad
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:34?LF_ae
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:35?LF_af
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:35?LF_ag
-rw-r--r--?1?hchen?hchen?52428800?05-10?18:35?LF_ah
-rw-r--r--?1?hchen?hchen?17344374?05-10?18:35?LF_ai

[hchen@RHELSVR5]#??cat?LF_*?>largefile.tar.gz

05 nl

nl命令其它和cat命令很像，只不過它會(huì)打上行號。如下所示：

[hchen@RHELSVR5?include]#?nl?stdio.h?|?head?-n?10
1??/*?Define?ISO?C?stdio?on?top?of?C++?iostreams.?????
?????2?????Copyright?(C)?1991,1994-2004,2005,2006?Free?Software?Foundation,?Inc.?????
?????3?????This?file?is?part?of?the?GNU?C?Library.?????
?????4?????The?GNU?C?Library?is?free?software;?you?can?redistribute?it?and/or?????
?????5?????modify?it?under?the?terms?of?the?GNU?Lesser?General?Public?????
?????6?????License?as?published?by?the?Free?Software?Foundation;?either?????
?????7?????version?2.1?of?the?License,?or?(at?your?option)?any?later?version.?????
?????8?????The?GNU?C?Library?is?distributed?in?the?hope?that?it?will?be?useful,

06 mkfifo

[hchen@RHELSVR5?~]#?mkfifo?/tmp/hchenpipe
[hchen@RHELSVR5?~]#?ls?-l?/tmp
prw-rw-r--?1?hchen??hchen??0?05-10?18:58?hchenpipe

[hchen@RHELSVR5?~]#?ls?-al?>?/tmp/hchenpipe

我們在另一個(gè)命令窗口中讀取這個(gè)管道中的信息：（其會(huì)導(dǎo)致上一個(gè)命令返回）

[hchen@RHELSVR5?~]#?head?/tmp/hchenpipe
drwx------?8?hchen?hchen????4096?05-10?18:27?.
drwxr-xr-x?7?root??root?????4096?03-05?00:06?..
drwxr-xr-x?3?hchen?hchen????4096?03-01?18:13?backup
-rw-------?1?hchen?hchen?????721?05-05?22:12?.bash_history
-rw-r--r--?1?hchen?hchen??????24?02-28?22:20?.bash_logout
-rw-r--r--?1?hchen?hchen?????176?02-28?22:20?.bash_profile
-rw-r--r--?1?hchen?hchen?????124?02-28?22:20?.bashrc
-rw-r--r--?1?root??root????14002?03-07?00:29?index.htm
-rw-r--r--?1?hchen?hchen???31465?03-01?23:48?index.php

07 ldd

這個(gè)命令可以知道你的一個(gè)可執(zhí)行文件所使用了動(dòng)態(tài)鏈接庫。如：

[hchen@RHELSVR5?~]#?ldd?/usr/bin/java
????????linux-gate.so.1?=>??(0x00cd9000)
????????libgij.so.7rh?=>?/usr/lib/libgij.so.7rh?(0x00ed3000)
????????libgcj.so.7rh?=>?/usr/lib/libgcj.so.7rh?(0x00ed6000)
????????libpthread.so.0?=>?/lib/i686/nosegneg/libpthread.so.0?(0x00110000)
????????librt.so.1?=>?/lib/i686/nosegneg/librt.so.1?(0x009c8000)
????????libdl.so.2?=>?/lib/libdl.so.2?(0x008b5000)
????????libz.so.1?=>?/usr/lib/libz.so.1?(0x00bee000)
????????libgcc_s.so.1?=>?/lib/libgcc_s.so.1?(0x00aa7000)
????????libc.so.6?=>?/lib/i686/nosegneg/libc.so.6?(0x0022f000)
????????libm.so.6?=>?/lib/i686/nosegneg/libm.so.6?(0x00127000)
????????/lib/ld-linux.so.2?(0x00214000)

08 col

這個(gè)命令可以讓你把man文件轉(zhuǎn)成純文本文件。如下示例：

#?PAGER=cat#?man?less?|?col?-b?>?less.txt

09 xmlwf

這個(gè)命令可以讓你檢查一下一個(gè)XML文檔是否是所有的tag都是正常的。如：

[hchen@RHELSVR5?~]#?curl?'https://coolshell.cn/?feed=rss2'?>?cocre.xml
??%?Total????%?Received?%?Xferd??Average?Speed???Time????Time?????Time??Current
?????????????????????????????????Dload??Upload???Total???Spent????Left??Speed
100?64882????0?64882????0?????0??86455??????0?--:--:--?--:--:--?--:--:--?2073k
[hchen@RHELSVR5?~]#?xmlwf?cocre.xml
[hchen@RHELSVR5?~]#?perl?-i?-pe?'s@@
@g'?cocre.xml
[hchen@RHELSVR5?~]#?xmlwf?cocre.xmlcocre.xml:13:23:?mismatched?tag

10 lsof

可以列出打開了的文件。

[root@RHELSVR5?~]#?lsof?|?grep?TCPhttpd???????548????apache????4u?????IPv6???14300967????TCP?*:http?(LISTEN)
httpd???????548????apache????6u?????IPv6???14300972????TCP?*:https?(LISTEN)
httpd???????561????apache????4u?????IPv6???14300967????TCP?*:http?(LISTEN)
httpd???????561????apache????6u?????IPv6???14300972????TCP?*:https?(LISTEN)
sshd???????1764??????root????3u?????IPv6???????4993????TCP?*:ssh?(LISTEN)
tcpserver??8965??????root????3u?????IPv4??153795500????TCP?*:pop3?(LISTEN)
mysqld????10202?????mysql???10u?????IPv4???73819697????TCP?*:mysql?(LISTEN)
sshd??????10735??????root????3u?????IPv6??160731956????TCP?210.51.0.232:ssh->123.117.239.68:31810?(ESTABLISHED)
sshd??????10767?????hchen????3u?????IPv6??160731956????TCP?210.51.0.232:ssh->123.117.239.68:31810?(ESTABLISHED)
vsftpd????11095??????root????3u?????IPv4??152157957????TCP?*:ftp?(LISTEN)