What is the Best Way to Perform Timestamp Comparison in Bash

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

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