Add Grep Over Commit Messages as a git til.

README.md

@@ -67,6 +67,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Dry Runs in Git](git/dry-runs-in-git.md)
 - [Excluding Files Locally](git/excluding-files-locally.md)
 - [Grab A Single File From A Stash](git/grab-a-single-file-from-a-stash.md)
+- [Grep Over Commit Messages](git/grep-over-commit-messages.md)
 - [Ignore Changes To A Tracked File](git/ignore-changes-to-a-tracked-file.md)
 - [Intent To Add](git/intent-to-add.md)
 - [Last Commit A File Appeared In](git/last-commit-a-file-appeared-in.md)

git/grep-over-commit-messages.md

@@ -0,0 +1,14 @@
+# Grep Over Commit Messages
+
+The `git log` command supports a `--grep` flag that allows you to do a text
+search (using grep, obviously) over the commit messages for that repository.
+For the git user that writes descriptive commit messages, this can come in
+quite handy. In particular, this can be put to use in an environment where
+the standard process involves including ticket and bug numbers in the
+commit. For example, finding bug `#123` can be accomplished with:
+
+```bash
+$ git log --grep="#123"
+```
+
+See `man git-log` for more details.