Question

2

How to run a script before suspend?

rated 0 times [ 2] [ 0] / answers: 1 / hits: 558 / 1 Year ago, tue, march 28, 2023, 11:58:20

I want to run a cron job to wipe files for a ephemeral user on Ubuntu desktop 20.04. Since the system won't be powering fully off regularly(for which I could just use @reboot /path/to/my_script.sh ), is there a way to schedulae a cron job to run when the computer is suspended? Everything on Google I'm seeing is related to running cron jobs while the computer is suspended, but I'd like to use suspend, or waking as the trigger for this cron job.

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

laceanz

Add To Favorites

Follow

Total Points: 86

Total Questions: 113

Total Answers: 104

Location: Australia

Member since Thu, Jan 26, 2023

1 Year ago

answered 1 Year ago chilgirlguid · Accepted Answer

That kind of trigger is not what cron is designed for. Cron is a clock-based trigger. @reboot is a convenience added to cron.

For suspend/remove jobs, one solution is to use power management.

See man pm-suspend

Put your job in the /etc/pm/sleep.d/ directory.

It's not a cron job. You place complete scripts in the directory.

Use case to determine what occurs on sleep, and what occurs on resume:

case "${1}" in

   suspend)

      suspend_actions

      ;;

   resume)

      resume_actions

      ;;

esac

Another similar solution is to use systemd.

The main difference is to use /lib/systemd/system-sleep/ instead of /etc/pm/sleep.d/

Both of these methods can arguably be considered a bit hacky: Don't use them for real applications, nor for long delays to suspending. Use inhibit instead.