From the git-diff
manpage:
git diff [--options] <commit> <commit> [--] [<path>...]
For instance, to see the difference for a file "main.c" between now and two commits back, here are three equivalent commands:
$ git diff HEAD^^ HEAD main.c
$ git diff HEAD^^..HEAD -- main.c
$ git diff HEAD~2 HEAD -- main.c
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…