How do I delete an exported environment variable?
How do I delete an exported environment variable?
Question
Before installing gnuplot, I set the environment variable GNUPLOT_DRIVER_DIR = /home/gnuplot/build/src. During the installation, something went wrong.
I want to remove the GNUPLOT_DRIVER_DIR environment variable. How can I achieve it?
Accepted Answer
unset is the command you're looking for.
unset GNUPLOT_DRIVER_DIR
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Walkthrough of creating and deleting an environment variable in bash:
Test if the DUALCASE variable exists:
[email protected]:~$ env | grep DUALCASE
[email protected]:~$
It does not, so create the variable and export it:
[email protected]:~$ DUALCASE=1
[email protected]:~$ export DUALCASE
Check if it is there:
[email protected]:~$ env | grep DUALCASE
DUALCASE=1
It is there. So get rid of it:
[email protected]:~$ unset DUALCASE
Check if it's still there:
[email protected]:~$ env | grep DUALCASE
[email protected]:~$
The DUALCASE exported environment variable is deleted.
Extra commands to help clear your local and environment variables:
Unset all local variables back to default on login:
[email protected]:~$ CAN="chuck norris"
[email protected]:~$ set | grep CAN
CAN='chuck norris'
[email protected]:~$ env | grep CAN
[email protected]:~$
[email protected]:~$ exec bash
[email protected]:~$ set | grep CAN
[email protected]:~$ env | grep CAN
[email protected]:~$
exec bash command cleared all the local variables but not environment variables.
Unset all environment variables back to default on login:
[email protected]:~$ export DOGE="so wow"
[email protected]:~$ env | grep DOGE
DOGE=so wow
[email protected]:~$ env -i bash
[email protected]:~$ env | grep DOGE
[email protected]:~$
env -i bash command cleared all the environment variables to default on login.
Because the original question doesn't mention how the variable was set, and because I got to this page looking for this specific answer, I'm adding the following:
In C shell (csh/tcsh) there are two ways to set an environment variable:
set x = "something"setenv x "something"
The difference in the behaviour is that variables set with setenv command are automatically exported to subshell while variable set with set aren't.
To unset a variable set with set, use
unset x
To unset a variable set with setenv, use
unsetenv x
Note: in all the above, I assume that the variable name is 'x'.
credits:
https://www.cyberciti.biz/faq/unix-linux-difference-between-set-and-setenv-c-shell-variable/ https://www.oreilly.com/library/view/solaristm-7-reference/0130200484/0130200484_ch18lev1sec24.html
As mentioned in the above answers, unset GNUPLOT_DRIVER_DIR should work if you have used export to set the variable. If you have set it permanently in ~/.bashrc or ~/.zshrc then simply removing it from there will work.