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?
1832
votes
For those looking for how to do this in Fish shell see stackoverflow.com/questions/30703860/… (even though this question isn't for a specific shell)
– Elijah Lynn
5 Answers
195
votes
Walkthrough of creating and deleting an environment variable in bash:
Test if the DUALCASE variable exists:
el@apollo:~$ env | grep DUALCASE
el@apollo:~$
It does not, so create the variable and export it:
el@apollo:~$ DUALCASE=1
el@apollo:~$ export DUALCASE
Check if it is there:
el@apollo:~$ env | grep DUALCASE
DUALCASE=1
It is there. So get rid of it:
el@apollo:~$ unset DUALCASE
Check if it's still there:
el@apollo:~$ env | grep DUALCASE
el@apollo:~$
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:
el@apollo:~$ CAN="chuck norris"
el@apollo:~$ set | grep CAN
CAN='chuck norris'
el@apollo:~$ env | grep CAN
el@apollo:~$
el@apollo:~$ exec bash
el@apollo:~$ set | grep CAN
el@apollo:~$ env | grep CAN
el@apollo:~$
exec bash command cleared all the local variables but not environment variables.
Unset all environment variables back to default on login:
el@apollo:~$ export DOGE="so wow"
el@apollo:~$ env | grep DOGE
DOGE=so wow
el@apollo:~$ env -i bash
el@apollo:~$ env | grep DOGE
el@apollo:~$
env -i bash command cleared all the environment variables to default on login.
10
votes
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
