Detect used space over 90% threshold

check_used_space_limit.sh

#!/bin/bash

OK=0
WARNING=1
ERROR=2
UNKNOWN=3

used_space_limit=90

used_space=`df -k /dev/xvde1 | awk '{print $5}' | tail -1 | sed 's/%//g'`

if [[ $used_space -ge $used_space_limit ]] ; then
  echo "ERROR - current used space $used_space% >= threshold of $used_space_limit%"
  exit $ERROR
fi

exit $OK