Shell Script for checking disk space

 ADMIN="tyagi.ankur07@gmail.com"
    # set alert level 90% is default
    ALERT=80
    df -HP | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $6 }' | while read output;
    do
    #echo $output
    usep=$(echo $output | awk '{ print $1 }' | cut -d'%' -f1 )
    partition=$(echo $output | awk '{ print $2 }' )

#echo "usep=$usep"

    if [ $usep -ge $ALERT ]; then
    echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |
    mailx -s "Alert: Almost out of disk space on `hostname`  $usep" $ADMIN
    fi
    done