Find Last 10 authors for a certain file in Git

What is t开发者_Go百科he best (from performance point of view) way to find in Git the last 10 users who changed a certain file ?

For example I want to know the last 10 committers (not the last 10 commits) of file foo.txt

I'd try something like this in *nix systems (w/ bash)

git log --format=%an foo.txt |awk ' !x[$0]++' |head -10