Git can search diffs with the -S option (it's called pickaxe in the docs)
git log -S password
This will find any commit that added or removed the string
password. Here a few options:
-p: will show the diffs. If you provide a file (
-p file), it will generate a patch for you.
-G: looks for differences whose added or removed line matches the given regexp, as opposed to
-S, which "looks for differences that introduce or remove an instance of string".
--all: searches over all branches and tags; alternatively, use