You want to simplify a complicated SSH command line, or tailor SSH clients to operate differently per remote host.
Create a host alias in ~/.ssh/config:
~/.ssh/config: Host mybox HostName mybox.whatever.example.com User smith ...other options...
Then connect via the alias:
$ ssh mybox
OpenSSH clients obey configurations found in ~/.ssh/config. Each configuration begins with the word Host followed by an hostname alias of your invention.
Immediately following this line, and continuing until the next Host keyword or end of file, place configuration keywords and values documented on the ssh(1) manpage. In this recipe we include the real name of the remote machine (HostName), and the remote username (User):
Host work HostName mybox.whatever.example.com User smith
Other useful keywords (there are dozens) are:
IdentityFile ~/.ssh/my_alternate_key_dsa Choose a private key file Port 12345 Connect on an alternative port Protocol 2 Use only the SSH-2 protocol
ssh_config(5) defines the client configuration keywords.