Monitor disk space, send email when reaches

mailx_disk_monitor.sh

#!/bin/sh

# How full should the disk be allowed to get (percentage)?
warn_at=90

# get disk space info for all disks
df | grep "/dev/disk" | awk '{ print $1,$3,$4,$5,$6 }' > /tmp/space

# for each disk, determine if full
while read line
do
	used=`echo $line | cut -f2 -d ' '`
	free=`echo $line | cut -f3 -d ' '`
	percent=`echo $line | cut -f4 -d ' '`
	dirname=`echo $line | cut -f5 -d ' '`
	
	perc=`echo "$used/($free+$used)*100" | bc -l | sed 's/\.[0-9]*//'`
	if [ $perc -ge $warn_at ]
	then
		echo Warning! $dirname is $perc percent full! \
		| mailx -s 'disk getting full!' me@example.com
	fi
done < /tmp/space