Question

I’m trying to write a shell script that, when run, will set some environment variables that will stay set in the caller’s shell.

setenv FOO foo 

in csh/tcsh, or

export FOO=foo 

in sh/bash only set it during the script’s execution.

I already know that

source myscript 

will run the commands of the script rather than launching a new shell, and that can result in setting the ‘caller’s’ environment.

But here’s the rub:

I want this script to be callable from either bash or csh. In other words, I want users of either shell to be able to run my script and have their shell’s environment changed. So ‘source’ won’t work for me, since a user running csh can’t source a bash script, and a user running bash can’t source a csh script.

Is there any reasonable solution that doesn’t involve having to write and maintain TWO versions on the script?

Answer 1

Your shell process has a copy of the parent’s environment and no access to the parent process’s environment whatsoever. When your shell process terminates any changes you’ve made to its environment are lost. Sourcing a script file is the most commonly used method for configuring a shell environment, you may just want to bite the bullet and maintain one for each of the two flavors of shell.