How to detect being source'd as opposed to being run in a shell script?

Question

In python you can detect whether a script is executed as opposed imported by another script with this

if __name__ == '__main__':
    # We are run directly.

Is there a way in to do the same in a shell script? I have a couple of functions in script that I would like to be able to source, without executing them.

Why not just keep the safe stuff such as function declarations and env variables in the sourced file, and move any executing code to a different script file? — Håken Lid, Jun 09 '17 at 14:14
Your question doesn't appear to have any real relevance to the tag python, remove that tag? — DisappointedByUnaccountableMod, Jun 09 '17 at 14:20
@HåkenLid when a task calls for separating in multiple files, I tend to start thinking that maybe it's too big for a shell script. Unless it's about cluttering my .profile of course. ;-) — Chris Wesseling, Jun 09 '17 at 14:20
Did you try searching for a solution? https://stackoverflow.com/questions/2683279/how-to-detect-if-a-script-is-being-sourced — 123, Jun 09 '17 at 14:22
@barny I'm looking for the shell equivalent of something in Python. https://stackoverflow.com/q/573585/383793 is also tagged both [git] and [svn] — Chris Wesseling, Jun 09 '17 at 14:23
@123 yes, but nothing useful came up... How did you find this one? — Chris Wesseling, Jun 09 '17 at 14:25
@ChrisWesseling went on google and searched `check if script is sourced` — 123, Jun 09 '17 at 14:28

Chris Wesseling · Answer 1 · 2017-06-09T14:16:38.293

1

So far I've come up with these:

if [ "$0" != "bash" ]
then
    # We are run directly because
    # $0 == our filename
    # Or is it? It could be a different shell!
fi

and

if [ "$(basename $0)" = "foo.sh" ]
then
    # We are run directly, because $0 == our filename.
    # But what if we get mv'ed to some other filename???
fi

Are there any less brittle solutions?

edited Jun 09 '17 at 14:16

answered Jun 09 '17 at 13:59

Chris Wesseling

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Your first solution seems fine. If you want to support other shells, just add them to the condition. – Håken Lid Jun 09 '17 at 14:13

How to detect being source'd as opposed to being run in a shell script?

1 Answers1