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

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>)

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.

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

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