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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?
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If so, you can lexicographically compare your timestamp with the output of date -u -d '-10 minutes' +%Y%m%d%H%M%S (the -u assumes that your database timestamp is in UTC, which I'd advise).
You can use date +%s -d your_date to get the number of seconds since a fixed instance (1970-01-01, 00:00 UTC) called "epoch". Once you get that it's really easy to do almost anything with dates.
A bash script is a series of commands written in a file. These are read and executed by the bash program. The program executes line by line. For example, you can navigate to a certain path, create a folder and spawn a process inside it using the command line.
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 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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