How to grep 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

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

Answer 1

I am not sure, if that's what you want ...

You can use git show to see old content. See git usermanual for an example:

You can always view an old version of a file by just checking out the correct revision first. But sometimes it is more convenient to be able to view an old version of a single file without checking anything out; this command does that:

$ git show v2.5:fs/locks.c

Before the colon may be anything that names a commit, and after it may be any path to a file tracked by git.

then you can grep the output.

Answer 2

So are you trying to grep through older versions of the code looking to see where something last exists?

If I were doing this, I would probably use git bisect. Using bisect, you can specify a known good version, a known bad version, and a simple script that does a check to see if the version is good or bad (in this case a grep to see if the code you are looking for is present). Running this will find when the code was removed.

Answer 3

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

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

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

---

As Jakub Narębski comments:

• 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.

Answer 4

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

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

This will grep through all your commit text for regexp.

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 -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 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>)

If you run OS X, I have written an OS X Dashboard Widget summarizing this (and other Git commands) here.

Answer 5

These blog posts by Junio C Hamano (git maintainer) might be interesting for you:

• Linus's ultimate content tracking tool (about pickaxe search i.e. git log -S and blame)
• Fun with "git log --grep" (searching commit messages)
• Fun with "git grep"