Script to delete old files when disk getting full

autodelete.sh

#/bin/sh

# This script deletes old files when the disk is getting full.
# It will always delete the oldest file or directory. Can be run
# in a cronjob every few minutes.

# Configurables

STORAGEDIR=/var/backups

FILESYSTEM=$(df -h | grep -o '/dev/[a-z0-9]*') # or whatever filesystem to monitor
CAPACITY=90 # delete if FS is over $CAPACITY % of usage

# Proceed if filesystem capacity is over than the value of CAPACITY (using df POSIX syntax)
# using [ instead of [[ for better error handling.

CURR_CAPACITY=$(df -P $FILESYSTEM | awk '{ gsub("%",""); capacity = $5 }; END { print capacity }')

if [ $CURR_CAPACITY -gt $CAPACITY ]
then
        FILENAME=$(ls -1t $STORAGEDIR | tail -n1)
        rm -rf "$STORAGEDIR/$FILENAME"
        echo "$(date) Capacity: $CURR_CAPACITY % - Deleted: $STORAGEDIR/$FILENAME" >> ~/autodelete.log

fi