Set $PATH for current session in Terminal

Question

Hello,
I want to modify the environment variable $PATH for the current terminal session. To modify it in $HOME/.profile (etc) is no option.
So I created a shell script called envsetup.sh which contains
ATLAS_HOME=/Applications/Development/atl-plugin-sdk
PATH=$ATLAS_HOME/bin:$PATH
export ATLAS_HOME PATH
When I execute the script, $PATH will only modified while running the script but does not alter it for the current session. But then I copy and paste it into the terminal, $PATH gets modified for the current session. What's wrong with it? On my Linux box, it works ...

Answer 1

Linux box, it works ...
This CANNOT work on your Linux box.
When you run a shell script (Mac OS X, Linux, HP-UX, Solaris, Tru64 UNIX, AIX, etc...), the shell script is runs in a child process. Any environment variables set or changed in that child process get destroyed when that child process ends, which happens as soon as the script ends. The parent process (your shell) will never see those child process environment variables. This has been true since the earliest versions of UNIX that I am aware of, and that goes back to at least '79.
Alternative approaches. You could create a shell function in your .profile
envsetup()
export ATLAS_HOME="/Applications/Development/atl-plugin-sdk"
export PATH="$ATLAS_HOME/bin:$PATH"
The next time you login, your .profile will run and you will have a new command "envsetup". When you invoke the command envsetup it will run within the context of your current shell, so those environment variables will be set and visible.
You could also create an alias that sources your envsetup.sh
alias envsetup 'source /path/to/envsetup.sh'
This would give you an easy to call command that would source into the current shell the export commands, as well as provide you with a script that can be sourced into other scripts that happen to need those specific exports.
Message was edited by: BobHarris