Email notification about logged in user

Bash login notification

Naming file

notify.sh

#!/bin/bash
# Put this script in /etc/profile for autorun.

num=1

# Search login record in /var/log/auth.log down up
while :
do
    # Next line
    string=$(tail -n $num /var/log/auth.log | head -n 1)

    # 6th word (it should be "Accepted")
    auth=$(echo $string | awk '{print $6}')

    if [ "$auth" == 'Accepted' ]
    then
        user=$(echo $string | awk '{print $9}')
        address=$(echo $string | awk '{print $11}')
        month=$(echo $string | awk '{print $1}')
        day=$(echo $string | awk '{print $2}')
        time=$(echo $string | awk '{print $3}')
        # Send to admin by email
        echo "$user logged in from $address at $time ($month $day)" | mailx -s "router login $(date '+%d.%m')" admin@example.com
        break
    fi

    # Go to next line
    num=$((num + 1))
done