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This tutorial explains Linux “env” command, options and its usage with examples.

env – run a program in a modified environment.

DESCRIPTION

Displays the current environment or sets the environment for the execution of a command.

SYNOPSIS

To Display Multiple Environment Variables

env [ -i | -u ] [Name=Value ]… [Command [ Argument … ] ]

To Display A Single Environment Variable

env [Name]

Set each NAME to VALUE in the environment and run COMMAND.

OPTIONS

-i, –ignore-environment
start with an empty environment
-u, –unset=NAME
remove variable from the environment

EXAMPLES

1. To change the TZ environment variable while running the date command

$ env TZ=MST7MDT date

2. To run the make command in an environment that consists only of definitions for the PATH, IDIR, and LIBDIR environment variables

$ env -i PATH=$PATH IDIR=/$HOME/include LIBDIR=/$HOME/lib make

You must specify the PATH environment variable so that the shell can find the make command. When the make command is finished, the previous environment takes effect.

3. Viewing all environment variables

$ env
SSH_AGENT_PID=2076
GPG_AGENT_INFO=/run/user/mohakkataria/keyring-06hbuU/gpg:0:1
TERM=xterm
SHELL=/bin/bash
XDG_SESSION_COOKIE=f16900caaa04f54976c81f94527ce78c-1387792950.638929-617127717
WINDOWID=65011717
GNOME_KEYRING_CONTROL=/run/user/mohakkataria/keyring-06hbuU
GTK_MODULES=overlay-scrollbar
USER=mohakkataria
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00: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:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=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:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=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:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=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:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
SSH_AUTH_SOCK=/run/user/mohakkataria/keyring-06hbuU/ssh
SESSION_MANAGER=local/ubuntu:@/tmp/.ICE-unix/2031,unix/ubuntu:/tmp/.ICE-unix/2031
DEFAULTS_PATH=/usr/share/gconf/ubuntu.default.path
XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
PATH=/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
DESKTOP_SESSION=ubuntu
PWD=/home/mohakkataria
GNOME_KEYRING_PID=2020
LANG=en_US.UTF-8
MANDATORY_PATH=/usr/share/gconf/ubuntu.mandatory.path
UBUNTU_MENUPROXY=libappmenu.so
COMPIZ_CONFIG_PROFILE=ubuntu
GDMSESSION=ubuntu
SHLVL=1
HOME=/home/mohakkataria
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
LOGNAME=mohakkataria
COMPIZ_BIN_PATH=/usr/bin/
XDG_DATA_DIRS=/usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-Uwk3cebEbY,guid=489d2bd3661a071ca0eddfdb52b80a36
LESSOPEN=| /usr/bin/lesspipe %s
TEXTDOMAIN=im-config
XDG_RUNTIME_DIR=/run/user/mohakkataria
DISPLAY=:0
XDG_CURRENT_DESKTOP=Unity
LESSCLOSE=/usr/bin/lesspipe %s %s
TEXTDOMAINDIR=/usr/share/locale/
COLORTERM=gnome-terminal
XAUTHORITY=/home/mohakkataria/.Xauthority
_=/usr/bin/env

“env” Command Usage Examples in Linux