github ssh/config
http://help.github.com/multiple-keys/
$ vi ~/.ssh/config ----- Host github.com HostName github.com User git IdentityFile /Users/joe/.ssh/id_rsa -----
http://help.github.com/multiple-keys/
$ vi ~/.ssh/config ----- Host github.com HostName github.com User git IdentityFile /Users/joe/.ssh/id_rsa -----