$ cd testGit/
$ ls
first.txt second.txt
$ git log --oneline
9c88fb7 add second lines to 1st & 2nd files
9c3da6c add 1st & 2nd files
$ git diff 9c88fb7 9c3da6c first.txt
warning: LF will be replaced by CRLF in first.txt.
The file will have its original line endings in your working directory