Git search for string in a single file's history

For this purpose you can use the -S option to git log:

git log -S'bar' -- foo.rb

Or maybe you can try this one (from related questions Search all of git history for string)

git rev-list --all foo.rb | (
    while read revision; do
        git grep -F 'bar' $revision foo.rb
    done
)

It will actually look for file content and not commit messages/patches for any occurence of bar.

There's an override for git log command (from manual):

$ git log Makefile      # commits that modify Makefile

So you could use:

git log foo.rb | grep "bar"

Related