OS X CLI Open and Kill an App

#!/usr/bin/env bash

case ${1} in
      "open")
      open /Applications/Yahoo\!\ Messenger.app/;
      let "myentry = `ps -au lance | grep /Applications/Yahoo\!\ Messenger.app/ | grep -v grep | awk '{print $2}'`";
      echo "press enter to kill ${myentry}";
      read;
      kill $myentry; 
      clear;
      ps -au lance | grep /Applications/Yahoo\!\ Messenger.app/ | grep -v grep; 
       exit;;
   "") ls $0;cat $0;exit;;
esac