Get an email whenever someone SSH's into your computer. (Taken from http://apple.stackexchange.com/questions/45688/getting-notified-when-someone-logs-into-a-server-using-ssh-or-remote-desktop/45705#45705)

detectSSH.sh

#!/usr/bin/env bash

mm=`date +%b`
dd=`date $1 +%d`
dd=`expr $dd`
if [ "$dd" -ge "10" ]
  then 
    dt=`echo "$mm $dd"` 
  else 
    dt=`echo "$mm  $dd"` 
fi

cat /var/log/secure.log | grep -E '(Accepted|SUCCEEDED)'| grep "$dt" >> /tmp/access_granted

/usr/bin/mail -E -s "Access granted" email@myserver.com < /tmp/access_granted
rm /tmp/access_granted