Have you tried using the config file? I beleive it would be more simple. 

create a config file for you user, usually ~/.ssh/config

In it you can put the following

host=host1

user=root

host=host2

user=admin

port=23230

 You can also use wildcards

host=*domain.com

port=12345

Personnaly I have to connect to many servers as the user admin, so I have the following:

host *

user=admin 

another useful option is

ControlMaster auto

ControlPath /tmp/%h

this creates a control file in /tmp. This lets you open new sessions on the same host without reauthenticating yoruself. I put this in the host * block.

Since scp/rsync etc use ssh, these settings apply to them also. In addition these specify "defaults". For example even though I specify admin as the user for all hosts, if I run ssh root@host it will overwrite the setting and conenct as root.

Hope these help :)