How to set environment variable in Linux permanently [closed]

If you want to set a variable in your shell (as opposed to the superuser's):

1. Make sure your .bashrc exists

ls -A ~/.bashrc

2. Add your variable at the bottom

export VARIABLE=value

3. Save, then open a new terminal and verify the variable is set

$ echo $VARIABLE
value

Keep in mind this depends on your shell.

Solution: In order to export and keep environment variables persistent on linux you should export variables decelration into one of the following files: ~/.bash_profile / ~/. bash_login / ~/.profile.

When bash is invoked as an interactive/non-interactive login shell, it first reads and executes commands from the file /etc/profile (if exists) and after looks for these following files ( in that order and do the same) ~/.bash_profile, ~/. bash_login, ~/.profile.

Example: adding secret token into my user profile.

cat << End >> ~/.profile
export SECRET_TOKEN=abc123!@#
End

output:

echo $SECRET_TOKEN
abc123!@#

The usual place is ~/.bashrc assuming that you're using bash, which is the default in most distributions. Check yourself with echo $SHELL. You may use ~/.bash_profile, if you only want to set the variable in login shells (but i.e. not in scripts).

Set it in /etc/environment. In my Ubuntu installation this is the place where you can set environment variables persistently. The file may be different for a different distribution. Following is the contents of my /etc/environment file.

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"

See how the environment variable PATH is being set above.

A note on export command

export varname makes variable varname available to any subshell run from the your current shell, i.e. the shell on which you ran the export command. Any other shell, which is either unrelated to your current shell or is a parent will not have this variable. Knowing this, assuming you are using bash shell, you can write the export command in .bashrc file. .bashrc is a file which is run every time a bash shell is started, and hence any command you write in it gets executed in any bash shell opened. Thus writing the export command in the .bashrc file is another option. Similar will be the process for any other shell you are using. for eg. for Z shell the file is .zshrc.

This is working inside Debian 11. It should work on other Debian based distributions like Ubuntu etc. I am using the old school nano to edit the file named pam_env.conf that resides in /etc/security/ directory, you may use whatever else you want instead of nano.

sudo nano /etc/security/pam_env.conf

Format for setting the environment variable inside this file is following:

VARIABLE [DEFAULT=[value]] [OVERRIDE=[value]]

(For example, let's set DXVK_HUD variable with the value full. This is equivalent to export DXVK_HUD=full You can replace the variable name and it's value to whatever you want for your use cases.)

This is how it is going to look inside that file as a new line:

DXVK_HUD DEFAULT=full OVERRIDE=full

Make the changes by saving it ( CTRL+O key combination is used for making changes through nano). Then press return (Enter key). And then press CTRL+X to exit from nano.

Restart your system. And type env in Terminal and see if you can see your environment variable in the list. It should be there.

there's a good explanation of when to put it where here : http://www.linuxfromscratch.org/blfs/view/6.3/postlfs/profile.html if you don't have root access put it somewhere local like .bash_profile or depending on which shell you use. Find your shell by typing the command ps .

To create an environment variable from a Bash shell script:

declare -x [variable_name]=[variable_value] works well...

Example:

declare -x MY_VARIABLE=value

to check, go to another logged in terminal session and type:

env | grep MY_VARIABLE   ; this will confirm it has been created and 
                         ; is accessible by other processes