check git diff of file code example

Example 1: git diff two commits one file

$ git diff HEAD^^ HEAD main.c
$ # show diff between HEAD(current commit) and HEAD^^(two commits back) for main.c

Example 2: git diff between one file

Just specify your local branch1 or remote origin/branch2
git diff branch1 origin/branch2	#show diff referenced from second branch
git diff branch1 branch2 file.txt #show diff only between file.txt