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