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Make git grep recurse into submodules

By David Christensen · Monday, April 26, 2010

Tags: git

If you've done any major work with projects that use submodules, you may have been surprised that git grep will fail to return matches that match in a submodule itself. If you go into the specific submodule directory and run the same git grep command, you will be able to see the results, so what to do in that case?

Fortunately, git submodule has a subcommand which lets us execute arbitrary commands in all submodule repos, intuitively named git submodule foreach.

My first attempt at a command to search in all submodules was:

$ git submodule foreach git grep {pattern}

This worked fine, except when {pattern} was multiple words or otherwise needed shell escaping. My next attempt was:

$ git submodule foreach git grep "{pattern}"

This properly passed the escapes to the shell (ending up with "'multi word phrase'" in my case), however an additional problem surfaced; the return value of the command resulted in an abort of the foreach loop. This was solved via:

$ git submodule foreach "git grep {pattern}; true"

A more refined version could be created as a git alias, automatically escape its arguments, and union with the results of git grep, thus providing the submodule-aware git grep I'd been hoping existed already. I leave this as an exercise to the reader... :-)

It's also worth noting that the file paths reported are relative to the containing submodule, so you would need to incorporate the git submodule foreach-supplied $path variable to pinpoint the full paths of the files in question.

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