Shutdown command with specific Date and Time

hack3rcon · 03-08-2017, 12:33 AM

Hello.
How can I shutdown my system via "shutdown" command in specific Date and Time? I know that with "shutdown -h " I can specific a hours but how about Date?
For example, I want to shutdown my system at 23:00 tomorrow.

Thank you.

chrism01 · 03-08-2017, 12:39 AM

Try the 'at' cmd; its good for one shot deals. For regular ones, cron is popular.

JJJCR · 03-08-2017, 04:11 AM

edit /etc/crontab

59 23 * * * root shutdown -h now

Shutdown the machine everyday at 11:59PM

--------------

shutdown -h +30 "Server is going to shutdown 30 minutes from now, save your work or delete all your files."

michaelk · 03-08-2017, 06:59 AM

In addition for the date you can specify the day of the week i.e thu (4) or day of the month i.e 9. Tomorrow being Thursday and the ninth day of the March.

It is also possible to use the date command for a specific date.

ondoho · 03-09-2017, 02:09 AM

from "man shutdown":

Code:

 shutdown may be used to halt, power-off or reboot the machine.

       The first argument may be a time string (which is usually "now").

hydrurga · 03-09-2017, 04:35 AM

Quote:

Originally Posted by ondoho

from "man shutdown":

Code:

 shutdown may be used to halt, power-off or reboot the machine.

       The first argument may be a time string (which is usually "now").

Yes, but it goes on to say:

Code:

The time string may either be in the format "hh:mm" for hour/minutes
       specifying the time to execute the shutdown at, specified in 24h clock
       format. Alternatively it may be in the syntax "+m" referring to the
       specified number of minutes m from now.  "now" is an alias for "+0",
       i.e. for triggering an immediate shutdown. If no time argument is
       specified, "+1" is implied.

The OP wants to shutdown with a specific date and time (and I'm sure doesn't want to have to calculate how many minutes ahead that particular date/time is).

rknichols · 03-09-2017, 09:22 AM

Quote:

Originally Posted by hydrurga

(and I'm sure doesn't want to have to calculate how many minutes ahead that particular date/time is).

Yes, that would be so hard to put in a script:

Code:

#!/bin/bash
Flags=
while [[ "$1" =~ ^- ]]; do
    Flags="$Flags $1"
    shift
done
When=$(date -d "$1" +%s) || exit
shift
shutdown $Flags +$(((When - $(date +%s))/60)) $*

Then you can run

Code:

myshutdown -P "11:30PM next Tuesday" OMG it\'s almost Wednesday

hack3rcon · 03-11-2017, 09:28 AM

Quote:

Originally Posted by chrism01

Try the 'at' cmd; its good for one shot deals. For regular ones, cron is popular.

Can you show me an example of "at" ?

ondoho · 03-11-2017, 01:27 PM

Quote:

Originally Posted by hack3rcon

Can you show me an example of "at" ?

https://duckduckgo.com/?q=linux+example+of+at

wpeckham · 03-11-2017, 01:44 PM

Quote:

Originally Posted by chrism01

Try the 'at' cmd; its good for one shot deals. For regular ones, cron is popular.

I never set up cron to reboot or shutdown a machine, but I do use 'at' for this purpose often.
Example:

Code:

echo "shutdown -r now" | at 23:59

Check the man page and online examples linked in other postings here for ways to express exact dates and times for the 'at' command. This is a very useful technique.

hack3rcon · 03-14-2017, 08:15 AM

Quote:

Originally Posted by wpeckham

I never set up cron to reboot or shutdown a machine, but I do use 'at' for this purpose often.
Example:

Code:

echo "shutdown -r now" | at 23:59

Check the man page and online examples linked in other postings here for ways to express exact dates and times for the 'at' command. This is a very useful technique.

Why not use "shutdown -h 23:59" ?

wpeckham · 03-14-2017, 12:29 PM

Quote:

Originally Posted by hack3rcon

Why not use "shutdown -h 23:59" ?

A couple of reasons:
1. I can control at both remotely and on the terminal easier, in the case I change my mind.
2. This works the same on all of my machines, while some of them have 'shutdown' commands that specify parameters differently.

I am used to running a mixed bag of RHEL, CentOS, Debian, SUSE, Ubuntu Server, AIX, HP-UX, Tru64Unix, and a couple less usual. (No more SCO, thank goodness!) The versions are all over the place, and some of them implement 'shutdown' as an executable, others as scripts. I had created a local manual of the "things that work everywhere except Windows" at my last workplace: this was one item in that document.

There is not likely to be any good reason for avoiding the form above as long as you are running any currently supported Linux version with near standard GNU utilities. I would just check your local man pages first, to be sure your environment is one where that does what you want. I HATE dragging a newbie into version limbo or giving advice that fails them. I figure they (mostly) deserve better from me. And that is all there is about that.

Meanwhile, back at the forums ...