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:

Answer 1

My favorite way to do it is with git log's -G option (added in version 1.7.4).

-G<regex>
       Look for differences whose added or removed line matches the given <regex>.

There is a subtle difference between the way the -G and -S options determine if a commit matches:

• The -S option essentially counts the number of times your search matches in a file before and after a commit. The commit is shown in the log if the before and after counts are different. This will not, for example, show commits where a line matching your search was moved.
• With the -G option, the commit is shown in the log if your search matches any line that was added, removed, or changed.

Take this commit as an example:

diff --git a/test b/test
index ffffdc242..60a8ba6 100644
--- a/test
+++ b/test
@@ -1 +1 @@
-hello hello
+hello goodbye hello

Because the number of times "hello" appears in the file is the same before and after this commit, it will not match using -Shello. However, since there was a change to a line matching hello, the commit will be shown using -Ghello.

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.

---

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.

Answer 3

git log can be a more effective way of searching for text across all branches, especially if there are many matches, and you want to see more recent (relevant) changes first.

git log -p --all -S 'search string'
git log -p --all -G 'match regular expression'

These log commands list commits that add or remove the given search string/regex, (generally) more recent first. The -p option causes the relevant diff to be shown where the pattern was added or removed, so you can see it in context.

Having found a relevant commit that adds the text you were looking for (for example, 8beeff00d), find the branches that contain the commit:

git branch -a --contains 8beeff00d

Answer 4

Whenever I find myself at your place, I use the following command line:

git log -S "<words/phrases i am trying to find>" --all --oneline  --graph

Explanation:

1. git log - Need I write more here; it shows the logs in chronological order.
2. -S "<words/phrases i am trying to find>" - It shows all those Git commits where any file (added/modified/deleted) has the words/phrases I am trying to find without '<>' symbols.
3. --all - To enforce and search across all the branches.
4. --oneline - It compresses the Git log in one line.
5. --graph - It creates the graph of chronologically ordered commits.

Answer 5

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 6

git rev-list --all | xargs -n 5 git grep EXPRESSION

is a tweak to Jeet's solution, so it shows results while it searches and not just at the end (which can take a long time in a large repository).