Linux: List All Environment Variables Command

b) env command – Print all exported environment or run a program in a modified environment.

c) set command – Print the name and value of each shell variable.

Examples

I recommend that you use the printenv command:

printenv

OR

printenv | less

OR

printenv | more

Sample outputs:

Fig.01: Command to see a list of all currently defined environment variables in a Linux bash terminal

A list of the commonly used variables in Linux

set and env command

You can use the env / set command too:

env
env | more
set 
set | more

Sample outputs:

HOME=/home/vivek
vivek@nas01:~$ env
TERM=xterm-256color
SHELL=/bin/bash
XDG_SESSION_COOKIE=9ee90112ba2cb349f07bfe2f00002e46-1381581541.324726-906214463
SSH_CLIENT=192.168.1.6 60190 22
SSH_TTY=/dev/pts/1
USER=vivek
MAIL=/var/mail/vivek
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
PWD=/home/vivek
LANG=en_IN
SHLVL=1
HOME=/home/vivek
LANGUAGE=en_IN:en
LOGNAME=vivek
SSH_CONNECTION=192.168.1.6 60190 192.168.1.10 22
_=/usr/bin/env

A note about env/set command

The env will only display a list of environment variables that have been exported and it will not show all bash variables. The set command allows you to change the values of shell options and set the positional parameters, or to display the names and values of shell variables. If no options or arguments are supplied, set displays the names and values of all shell variables and functions, sorted according to the current locale, in a format that may be reused as input for setting or resetting the currently-set variables. Hence, I recommend that you use printenv command to dump the list of all shell variables on screen. To save the list of all shell environment variables to a file, enter:

printenv > env.txt
cat env.txt

Use the grep command to search for particular variable:

printenv | grep foo
printenv | grep HOME

Recommend readings

• Bash shell variables from the Linux shell scripting wiki.
• Man pages: env(1)