Shell Programming and Scripting

[root@redhat ~]# chage -l user1
Last password change                                    : Jul 08, 2015
Password expires                                        : Oct 06, 2015
Password inactive                                       : never
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 90
Number of days of warning before password expires       : 7

cat /etc/shadow | cut -d: -f1,8 | sed /:$/d > /tmp/expirelist.txt
totalaccounts=`cat /tmp/expirelist.txt | wc -l`
for((i=1; i<=$totalaccounts; i++ ))
       do
       tuserval=`head -n $i /tmp/expirelist.txt | tail -n 1`
       username=`echo $tuserval | cut -f1 -d:`
       userexp=`echo $tuserval | cut -f2 -d:`
       userexpireinseconds=$(( $userexp * 86400 ))
       todaystime=`date +%s`
       #check if the user expired or not?
       if [ $userexpireinseconds -ge $todaystime ] ;
           then
           timeto7days=$(( $todaystime + 604800 ))
                if [ $userexpireinseconds -le $timeto7days ];
                then
                mail -s "The account $username will expire less than 7 days" root
                fi
       else
       mail -s "The user account $username already expired" root
       fi
done