df --output=pcent / | tail -n +2 | tr -cd '0-9\n'
output available percent without header and symbol '%' - only number
#!/bin/bash
for mnt in / /var/log /var/www /mnt/shared; do
chk_avail=`df --output=pcent $mnt | tail -n +2 | tr -cd '0-9\n'`
flg=`echo $(( 100 - $chk_avail ))`
if [ $flg -lt 15 ]; then
echo 'Dataserver lack of free space, only '$flg' percent available in '$mnt' partition' | mail -s 'Dataserver lack of free space' alerts@gmail.com
fi
done
