put this file under ~/.gitconfig

gitconfig

[alias]
        co = checkout
        br = branch
        ci = commit
        st = status -uno
        mylog = !git log --author=\"$(git config user.name)\"
        viewchanges= diff -v  --stat --cached origin/master
[user]
        name = Jiachen Ning
        email = jiachenning@gmail.com
[core]
        excludesfile = /Users/ninja/.gitignore_global
        autocrlf = input
[difftool "sourcetree"]
        cmd = opendiff \"$LOCAL\" \"$REMOTE\"
        path =