Linux env command - Set environment variables

Linux environment variables are settings for user's terminal environment, such as system path, application setting, and default shell. Setting Linux environment is like setting your workplace. It can greatly improve your work. You can customize Linux environment and set almost everything in your Linux system to be the way you want.

Linux env command

The Linux env command is used to manage Linux system environment. Invoking env command with no option will print environment variables for the current user. Here is an example of env command invoke by the first user in Ubuntu system.

[email protected]:~$ env
TERM=xterm
SHELL=/bin/bash
SSH_CLIENT=192.168.44.1 4019 22
SSH_TTY=/dev/pts/0
USER=luzar
LS_COLORS=no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:
su=37;41:sg=30;43:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.svgz=01;31:*.arj=01;31:
*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.bz2=01;31:
*.bz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:
*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:
*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.mng=01;35:
*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:
*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:
*.avi=01;35:*.fli=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.aac=00;36:*.au=00;36:
*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:
MAIL=/var/mail/luzar
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
PWD=/home/luzar
LANG=en_US.UTF-8
HISTCONTROL=ignoreboth
SHLVL=1
HOME=/home/luzar
LOGNAME=luzar
SSH_CONNECTION=192.168.44.1 4019 192.168.44.128 22
LESSOPEN=| /usr/bin/lesspipe %s
LESSCLOSE=/usr/bin/lesspipe %s %s
_=/usr/bin/env
[email protected]:~$

As you can see from the example above, the Linux env format is set like `VARIABLE=VALUE', where the environment variable VARIABLE is set to value VALUE. The VALUE may be empty (`VARIABLE='). Setting a variable to an empty value is different from unsetting it. A variable is evaluate from left-to-right, so if two same variables are mentioned, the earlier variable is ignored.

The first operand that does not contain the character `=' specifies the program to invoke; it is searched for according to the `PATH' environment variable.

[email protected]:~$ env --help
Usage: env [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]
Set each NAME to VALUE in the environment and run COMMAND.

-i, --ignore-environment start with an empty environment
-u, --unset=NAME remove variable from the environment
--help display this help and exit
--version output version information and exit

A mere - implies -i. If no COMMAND, print the resulting environment.

Report bugs to .
[email protected]:~$

If you need more information about Linux environment variables, a complete Linux env tutorial is available in your Linux system. You can view it by invoking info coreutils env invocation in the command line terminal like the example below:

[email protected]:~$ info coreutils env invocation

Back to Linux basic commands main page.

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