Monday, February 21, 2022

[SOLVED] Test whether a glob has any matches in Bash

Issue

If I want to check for the existence of a single file, I can test for it using test -e filename or [ -e filename ].

Supposing I have a glob and I want to know whether any files exist whose names match the glob. The glob can match 0 files (in which case I need to do nothing), or it can match 1 or more files (in which case I need to do something). How can I test whether a glob has any matches? (I don't care how many matches there are, and it would be best if I could do this with one if statement and no loops (simply because I find that most readable).

(test -e glob* fails if the glob matches more than one file.)


Solution

Bash-specific solution:

compgen -G "<glob-pattern>"

Escape the pattern or it'll get pre-expanded into matches.

Exit status is:

  • 1 for no-match,
  • 0 for 'one or more matches'

stdout is a list of files matching the glob. I think this is the best option in terms of conciseness and minimizing potential side effects.

Example:

if compgen -G "/tmp/someFiles*" > /dev/null; then
    echo "Some files exist."
fi


Answered By - Brian Chrisman
Answer Checked By - Marilyn (WPSolving Volunteer)
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