Script to send mail if there has been no entry in a log file for a certain amount of time

Question

I am new to shell scripting. How would I write a script which can send an alert mail if there is no entry in the log file for more than 3 hours.

Answer 1

A bit convoluted, but it works:

#!/bin/bash

now=`date +%s`
max_age=10800 # 3 hours in seconds

if [ $(($now - `stat -c '%Y' $1`)) -gt $max_age ]; then
    echo "file hasn't been updated in $max_age seconds"
fi

Call the script with the filename as the only argument.