How do I delete an exported environment variable?
Walkthrough of creating and deleting an environment variable in bash:
Test if the DUALCASE variable exists:
el@apollo:~$ env | grep DUALCASEel@apollo:~$ It does not, so create the variable and export it:
el@apollo:~$ DUALCASE=1el@apollo:~$ export DUALCASECheck if it is there:
el@apollo:~$ env | grep DUALCASEDUALCASE=1It is there. So get rid of it:
el@apollo:~$ unset DUALCASECheck if it's still there:
el@apollo:~$ env | grep DUALCASEel@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 CANCAN='chuck norris'el@apollo:~$ env | grep CANel@apollo:~$el@apollo:~$ exec bashel@apollo:~$ set | grep CANel@apollo:~$ env | grep CANel@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 DOGEDOGE=so wowel@apollo:~$ env -i bashel@apollo:~$ env | grep DOGEel@apollo:~$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 xTo unset a variable set with setenv, use
unsetenv xNote: 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