I want to find the most recent commit that modified a source file.
I can use
git log supports looking at the history of specific files (and directories), so you can write this:
git log my/file.c
If you really only want to list the one most recent commit, for example to use it in a script, you can use
git log -n 1 --pretty=format:%h -- my/file.c
git log to show only the commit hash (thanks to the TheBamf). The
-- separater stops the file name from getting interpreted as a commit name, just in case it's ambiguous.