24일차 수업
#add
#IP="$(echo $SSH_CONNECTION | cut -d " " -f 1)"
#HOSTNAME=$(hostname)
#NOW=$(date +"%e %b %Y, %a %r")
#echo 'Someone from '$IP' logged into IP_223 '$HOSTNAME' on '$NOW'.' | mail -s 'SSH Login Notification' log@mail.jeonjucom.kr
systemctl stop postfi