How to plan system shutdown in Devuan linux?

You already know, that to shut down system immediately, you can run a following command in linux terminal:

$ shutdown now

System will shutdown immediately. Surely, it you want to shutdown and then reboot it, you will run:

$ shutdown -r now

But sometimes you have to plan your shutdown (corporate rules, system maintenance, parental control etc). In this case you have just to pospone system shutdown using proper parameters while running "shutdown" command.

Postpone system shutdown

In order to just postpone system shutdown for 30 minutes you run:

$ shutdown +30

To postpone shutdown for 1 hour and 45 minutes, you run:

$ shutdown +105

In order you want to add some announcement to users, you just right the text of an announcement right after the number the shutdown is postponed:

$ +10 "Sorry, system upgrade is planned after 10 minutes. Please, save your details and log out!"

Planning a shutdown for certain time

In case you know exactly what time the system will shut down, you can write it directly. For example, your Devuan system is going to shutdown at 17:00, so you run the following command:

$ shutdown 17:00

Pay attention, that this way you set up shutdown by your local time. In case you plan server shutdown, server's time settings can be different, that user's.