check_time_machine_currency.sh

#!/bin/bash

#       Check Time Machine Currency
#       by Jedda Wignall
#       http://jedda.me

#       v1.1 - 3 May 2012
#       Cleaned up the output to provide a last backed up date. Error checking for non-supplied flags.

#       v1.0 - 3 May 2012
#       Initial release.

#       This script checks the time machine results file on a Mac, and reports if a backup has completed within a number of minutes of the current time.
#       Takes two arguments (warning threshold in minutes, critical threshold in minutes):
#       ./check_time_machine_currency.sh -w 240 -c 1440

#       Very useful if you are monitoring client production systems, and want to ensure backups are occurring.

while getopts "d:w:c:" optionName; do
case "$optionName" in
w) warnMinutes=( $OPTARG );;
c) critMinutes=( $OPTARG );;
esac
done

if [ "$warnMinutes" == "" ]; then
        printf "ERROR - You must provide a warning threshold with -w!\n"
        exit 3
fi

if [ "$critMinutes" == "" ]; then
        printf "ERROR - You must provide a critical threshold with -c!\n"
        exit 3
fi

lastBackupDateString=`defaults read /private/var/db/.TimeMachine.Results BACKUP_COMPLETED_DATE`

if [ "$lastBackupDateString" == "" ]; then
        printf "CRITICAL - Time Machine has not completed a backup on this Mac!\n"
        exit 2
fi

lastBackupDate=$(date -j -f "%Y-%m-%e %H:%M:%S %z" "$lastBackupDateString" "+%s" )
currentDate=$(date +%s)

diff=$(( $currentDate - $lastBackupDate))
warnSeconds=$(($warnMinutes * 60))
critSeconds=$(($critMinutes * 60))

if [ "$diff" -gt "$critSeconds" ]; then
        printf "CRITICAL - Time Machine has not backed up since `date -j -f %s $lastBackupDate` (more than $critMinutes minutes)!\n"
        exit 2
elif [ "$diff" -gt "$warnSeconds" ]; then
        printf "WARNING - Time Machine has not backed up since `date -j -f %s $lastBackupDate` (more than $warnMinutes minutes)!\n"
        exit 1
fi

if [ "$lastBackupDate" != "" ]; then
        printf "OK - A Time Machine backup has been taken within the last $warnMinutes minutes.\n"
        exit 0
else
        printf "CRITICAL - Could not determine the last backup date for this Mac."
        exit 2
fi