Linux unset command detailed linux unset command how to use

Unset for the shell built-in directives, you can delete variables or functions.

Grammar

unset [-fv][variable or function name]

Parameters:

• -F Deletes only functions.
• -v deletes only variables.

Instance

Delete environment variables

[root@w3cschool.cc ~]# lx= "LS-LH"//Setting environment variable

[root@w3cschool.cc ~]# $LX//Use environment variables

Total dosage 116K

-rw-r--r--1 root root 2.1K 2008-03-30 anaconda-ks.cfg

DRWX------3 root 4.0K March 21:22 Desktop

-rw-r--r--1 root root 50K 2008-03-30 Install.log

-rw-r--r--1 root root 32K 2008-03-30 Install.log.syslog

lrwxrwxrwx 1 Root 9 2008-03-30 qte->/opt/qte/

[root@w3cschool.cc ~]# set//view current environment variable

Bash=/bin/bash

Bash_argc= ()

bash_argv= ()

...... Omit part of the content

Prompt_command= ' Echo-ne ' 33]0;${user}@${hostname%%.*}:${pwd/# $HOME/~}07 "'

Ps1= ' [U@h w]$ '

Ps2= ' > '

ps4= ' + '

Pwd=/root

qtdir=/usr/lib/qt-3.3

Shell=/bin/bash

Ssh_tty=/dev/pts/4

Supported=zh_cn. Utf-8:zh_cn:zh:en_us. Utf-8:en_us:en

Sysfont=latarcyrheb-sun16

Term=xterm

Uid=0

User=root

_=-lh

lx= ' LS-LH '

[root@w3cschool.cc ~]# unset LX//delete environment variable

[root@w3cschool.cc ~]# set//display current environment variable

Bash=/bin/bash

Bash_argc= ()

bash_argv= ()

...... Omit part of the content

Prompt_command= ' Echo-ne ' 33]0;${user}@${hostname%%.*}:${pwd/# $HOME/~}07 "'

Ps1= ' [U@h w]$ '

Ps2= ' > '

ps4= ' + '

Pwd=/root

qtdir=/usr/lib/qt-3.3

Shell=/bin/bash

Ssh_tty=/dev/pts/4

Supported=zh_cn. Utf-8:zh_cn:zh:en_us. Utf-8:en_us:en

Sysfont=latarcyrheb-sun16

Term=xterm

Uid=0

User=root

_=-lh