Prevent temporally suspend/hibernate from script?

Question

Is there any way to prevent temporally suspend/hibernate from a script?

I want the screen to enter in powersave mode when appropriate, but the computer doesn't stop. Caffeine doesn't allow this: it disables all or nothing.

Why I want to do this? Because sometimes I download huge amount of files from a server via FTP. These downloads can take hours to complete.

Answer 1

To prvent hibernation, create /var/run/do-not-hibernate:

sudo touch /var/run/do-not-hibernate

The file /usr/lib/pm-utils/sleep.d/000kernel-change makes this work. If you need to disable suspend, create a new file for that, say /etc/pm/sleep.d/000_prevent_suspend_hibernate:

#!/bin/sh
# Prevents the machine from suspending or hibernating when
# the file /var/run/do-not-hibernate-or-suspend exist
case "$1" in
  suspend|hibernate)
    [ -f /var/run/do-not-hibernate-or-suspend ] && exit 1
    ;;
esac

Make it executable:

sudo chmod +x /etc/pm/sleep.d/000_prevent_suspend_hibernate

In case you need to prevent the machine from suspending or hibernating, create a file:

sudo touch /var/run/do-not-hibernate-or-suspend

After rebooting or removing this file, suspending and hibernating works again.

Answer 2

Simply add a file to /etc/pm/sleep.d In this file do you checks if suspend should be allowed. If not just exit with exit 1.

For example:

tmp_start=...
tmp_stop=...

if [ $((tmp_stop)) -gt $((current_date)) -a $((tmp_start)) -lt $((current_date)) ]; then
    logger $0: Currently RECORDING. No Suspend!
    exit 1;
fi