Linux disk space checker

checkSpace.sh

#!/bin/bash
# Disk space checking script.
# Version 0.2

# All of the below parameters can be overriden via command line arguments.
# Minimum disk space that should be available, in kilobytes.
THRESHOLD=20971520
# Partition/Filesystem that we should check.
PARTITION="/dev/md1"
# Email address that mail should be sent to.
MAILTO="emailaddress"
# Machine's name. Change to something other than `hostname -f` if you want to.
HOSTNAME="`hostname -f`"

while getopts "t:p:m:H:" OPTION
do
    case $OPTION in
        t)
            THRESHOLD=$OPTARG
            ;;
        p)
            PARTITION="$OPTARG"
            ;;
        m)
            MAILTO="$OPTARG"
            ;;
        H)
            HOSTNAME="$OPTARG"
            ;;
    esac
done

if [[ "`df | grep "${PARTITION}" | awk '{ print $4 }' | sed -r 's/[A-Z]//g'`" -lt "${THRESHOLD}" ]]; then
    (echo "Warning: Filesystem ${PARTITION} on ${HOSTNAME} is below the threshold of ${THRESHOLD}. DO SOMETHING!") | mailx -s "Disk Space on ${HOSTNAME} below ${THRESHOLD}" ${MAILTO}
fi
exit 0