UNIX for Advanced & Expert Users

how can we determine that which scripts ,binaries, utilities or something else uses a specific environment variable?

i have an environment variable EXTRAPATH in a shell script, and i want to determine if it is used by something else or it is absolutely useless.

Very simply answer, You cannot. I answered from best of my 5+ year experience.

If the env variable is an app specific env variable, then there might be a check for that in the app. A very crude way of finding out is strings app | grep EXTRAPATH. If at all it prints anything, you can not conclude on how this variable is used within the app.

What does the shell script do ? Call some executable ? If yes, then probably(?) that executable could be using it. Unset the env variable and try running the app. If it misbehaves, then you know whom to export.

Remember you can always set the PATH inside your scripts and then you would know what binaries the script was using.

Variables can get set in a users .profile for the env. That is a good place to look.

You could add these lines in your script as the 2nd and 3rd lines:
env
echo $PATH
exit

The script will run but it will exit right after it checks the environmental variables and the PATH.

Hope this helps.

-X

There is no easy way to find out what script-binary-app uses which environment variable, but variables set by scripts are only set while the script is running and will unset once the script exits. So, if your script is a standalone script, i.e., not part of an application, chances are that $EXTRAPATH is useless to anything but the script that sets it. If it is part of an application, there is a chance that the application would read it and use it even after the script has exited, but I doubt it.