Delete files if the mount they live on is getting full

tidy.sh

#!/bin/bash

# find out how much space is available on the partition /var/log/app resides upon
SPACE_USED=$(df -P /var/log/app | awk '{ if(NR>1)print }' | awk '{ print $5 }' | tr -d '%')
# set the threshold to clear at once breached (percentage)
SPACE_USED_MAX=80
# get the date in a format we can use
DATE=$(date '+%Y%m%d')

# if we're getting low on space where /var/log/app resides
if [ $SPACE_USED -ge $SPACE_USED_MAX ]; then
  # retrieve a list of trace directories
  for DIR in $(/bin/find /var/log/app/*/trace -mindepth 1 -maxdepth 1 -type d -exec ls -d '{}' \;); do
    DIR_BASENAME=$(basename $DIR)
    # if they're not from today
    if [ $DIR_BASENAME -ne $DATE ]; then
      # then delete them
      echo "Deleting:" $DIR
      rm -fr $DIR
    fi
  done
fi

# EOF