$ sudo nano /usr/sbin/su
#!/bin/bash

usage() {
  cat<<EOF
Usage:
 su <user>
EOF
  exit
}

[ "$#" != "1" ] && usage || ssh ${1}@${HOSTNAME}

$ sudo chmod +x /usr/sbin/su

# 清除歷史紀錄
$ cat /dev/null > ~/.bash_history && history -c