Question

I have an alert script that I am trying to keep from spamming me so I’d like to place a condition that if an alert has been sent within, say the last hour, to not send another alert. Now I have a cron job that checks the condition every minute because I need to be alerted quickly when the condition is met but I don’t need to get the email every munite until I get the issue under control. What is the best way to compare time in bash to accomplish this?

Answer 1

By far the easiest is to store time stamps as modification times of dummy files. GNU touch and date commands can set/get these times and perform date calculations. Bash has tests to check whether a file is newer than (-nt) or older than (-ot) another.

For example, to only send a notification if the last notification was more than an hour ago:

touch -d '-1 hour' limit if [ limit -nt last_notification ]; then     #send notification...     touch last_notification fi