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

Use the date command to convert the two times into a standard format, and subtract them. You'll probably want to store the previous execution time in a dotfile then do something like:

last = cat /tmp/.lastrun
curr = date '+%s'

diff = $(($curr - $last))
if [ $diff -gt 3600 ]; then
    # ...
fi

echo "$curr" >/tmp/.lastrun

(Thanks, Steve.)