How to grep (search) committed code in the Git history

Question

I have deleted a file or some code in a file sometime in the past. Can I grep in the content (not in the commit messages)?

A very poor solution is to grep the log:

git log -p | grep <pattern> 

However, this doesn't return the commit hash straight away. I played around with git grep to no avail.

Answer 1

To search for commit content (i.e., actual lines of source, as opposed to commit messages and the like), you need to do:

git grep <regexp> $(git rev-list --all) 

git rev-list --all | xargs git grep <expression> will work if you run into an "Argument list too long" error.

If you want to limit the search to some subtree (for instance, "lib/util"), you will need to pass that to the rev-list subcommand and grep as well:

git grep <regexp> $(git rev-list --all -- lib/util) -- lib/util 

This will grep through all your commit text for regexp.

The reason for passing the path in both commands is because rev-list will return the revisions list where all the changes to lib/util happened, but also you need to pass to grep so that it will only search in lib/util.

Just imagine the following scenario: grep might find the same <regexp> on other files which are contained in the same revision returned by rev-list (even if there was no change to that file on that revision).

Here are some other useful ways of searching your source:

Search working tree for text matching regular expression regexp:

git grep <regexp> 

Search working tree for lines of text matching regular expression regexp1 or regexp2:

git grep -e <regexp1> [--or] -e <regexp2> 

Search working tree for lines of text matching regular expression regexp1 and regexp2, reporting file paths only:

git grep -l -e <regexp1> --and -e <regexp2> 

Search working tree for files that have lines of text matching regular expression regexp1 and lines of text matching regular expression regexp2:

git grep -l --all-match -e <regexp1> -e <regexp2> 

Search working tree for changed lines of text matching pattern:

git diff --unified=0 | grep <pattern> 

Search all revisions for text matching regular expression regexp:

git grep <regexp> $(git rev-list --all) 

Search all revisions between rev1 and rev2 for text matching regular expression regexp:

git grep <regexp> $(git rev-list <rev1>..<rev2>) 

Answer 2

You should use the pickaxe (-S) option of git log.

To search for Foo:

git log -SFoo -- path_containing_change git log -SFoo --since=2009.1.1 --until=2010.1.1 -- path_containing_change 

See Git history - find lost line by keyword for more.

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As Jakub Narębski commented:

• this looks for differences that introduce or remove an instance of <string>. It usually means "revisions where you added or removed line with 'Foo'".

• the --pickaxe-regex option allows you to use extended POSIX regex instead of searching for a string. Example (from git log): git log -S"frotz\(nitfol" --pickaxe-regex

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As Rob commented, this search is case-sensitive - he opened a follow-up question on how to search case-insensitive.