appendix 4: host aliases

(or "making git use the right options for ssh")

The ssh command has several options for non-default items to be specified. Two common examples are -p for the port number if it is not 22, and -i for the public key file if you do not want to use just ~/.ssh/id_rsa or such.

Git has two ssh-based URL syntaxes, but neither allows specifying a non-default public key file. And a port number is only allowed in one of them. (See man git-clone for details). Finally, hosts often have to be referred with IP addresses (such is life), or the name is very long, or hard to remember.

Using a "host" para in ~/.ssh/config lets you nicely encapsulate all this within ssh and give it a short, easy-to-remember, name. Example:

host gitolite
    user git
    hostname a.long.server.name.or.annoying.IP.address
    port 22
    identityfile ~/.ssh/id_rsa

Now you can simply use the one word gitolite (which is the host alias we defined here) and ssh will infer all those details defined under it -- just say ssh gitolite and git clone gitolite:reponame and things will work.

(By the way, the 'port' and 'identityfile' lines are needed only if you have non-default values, although I put them in anyway just to be complete).

If you have more than one pubkey with access to the same server, you must use this method to make git pick up the right key. There is no other way to do this, as far as I know.