You could use ~/.ssh/config file.
#
# ~/.ssh/config
#
Host servername
Hostname 127.127.127.127
Port 22
User root
#EOF: config
Then simply connect with "ssh servername" and if you don't want to use password you can use SSH key. Here is good tutorial on how to do that > http://www.cyberciti.biz/tips/linux-multiple-ssh-key-based-authentication.html
If you just want to pass user/server from terminal, you can do this.
#!/bin/bash
sftp -b "$1"@"$2"
then use it like this './sftp.sh user server'
use SCP like this;
scp -P 22 user@server:/dir/file.tgz ~/Desktop/
use SFTP like this;
sftp user@server:/dir/file.tgz ~/Desktop/file.tgz
You can also try this;
sftp user@host <<EOF
get /dir/file.tgz
rm /dir/file.tgz
EOF