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1. Pgrep

There is a p before the pgrep name, we can guess that this is related to the process, it is grep again, of course, this is the grep command related to the process. However, this command is mainly used to enumerate the process ID. Such as:

$pgrep-u hchen2244122444

This command is equivalent to:

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

2. Pstree

This command lists the processes in a tree. As follows:

[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/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

3. Bc

The main purpose of this command is to do a mathematical operation with high precision. Such as opening the square root and so on. Here is a script we wrote using the bc command (file name: sqrt)

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

So, we can use this script to do the square root operation:

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

4. Split

If you have a large file and you want to divide it into small files, then this command is for this purpose.

[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- -LF_ac-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

File merging requires only a simple merge, such as:

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

5. Nl

The nl command is similar to the cat command, except that it is marked with a line number. As follows:

[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

6. Mkfifo

Anyone familiar with Unix should know that this is a system call or command that creates a named pipeline. Normally, we use a vertical bar "|" on the command line to string commands together using lifeless pipes. When we use mkfifo, we use well-known pipes. Here is an example: the following is to create a named pipe:

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

Then, we run the following command in a shell, which will not be returned unless someone reads the information from the named pipeline.

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

We read the information in this pipe in another command window: (it causes the previous command to return)

[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 17602-28 22:20 .bash _ profile-rw-r--r-- 1 hchen hchen 12402-28 22:20 .bashrc-rw-r- -r root root-1 root root 14002 03-07 00:29 index.htm-rw-r--r-- 1 hchen hchen 31465 03-01 23:48 index.php

7. Ldd

This command tells you that one of your executables uses a dynamic link library. Such as:

[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)

8. Col

This command allows you to convert man files to plain text files. The following is an example:

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

9. Xmlwf

This command allows you to check whether all tag in an XML document is normal. Such as:

[hchen@RHELSVR5 ~] # curl 'https://coolshell.cn/?feed=rss2' > cocre.xml% Total% Received% Xferd Average Speed Time Current Dload Upload Total Spent Left Speed 64882 64882 00 86455 0 -:-2073k [hchen@RHELSVR5 ~] # xmlwf cocre.xml [hchen@RHELSVR5] # perl-I-pe's request @

@ g'cocre.xml [hchen@RHELSVR5 ~] # xmlwf cocre.xmlcocre.xml:13:23: mismatched tag

10. Lsof

You can list open files.

[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 root 31810 (ESTABLISHED) sshd 10767 hchen 3u IPv6 160731956 TCP 210.51.0.2321956 TCP 210.51.0.2321810 (ESTABLISHED) vsftpd 11095 Root 3U IPv4 152157957 TCP *: ftp (LISTEN) above are all the contents of the article "10 commands in linux can increase productivity by 50%" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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