Git has a built-in grep command that works essentially the same as the standard grep command that unix users are used to. The benefit of git-grep is that it is tightly integrated with Git. You can search for occurrences of a pattern on another branch. For example, if you have a feature branch, my-feature, on which you’d like to search for occurrences of user.last_name, then your command would look like this:

$ git grep 'user\.last_name' my-feature

If there are matching results, they follow this format:

my-feature:app/views/users/show.html.erb:  <%= user.last_name %>
...

This formatting is handy because you can easily copy the branch and file directive for use with git-show.

See man git-grep for more details.