In this video, I'll tell you about ADD. ADD is to run specific use jobs at a specific
moment. In order to do so, the ADD service must be running. Otherwise, ADD can't do its
thing. And then you use ADD followed by a time to schedule a job. Next, you type one
or more job specifications in the ADD interactive shell and use CTRL-D to close the shell.
You might use ADD-Q for a list of jobs currently scheduled and ADD-RM if you want to remove
jobs from the list. Let me show you. So to start with, systemctl status ADD. You can
see ADD is running. Well, that's nice. What is the time at this moment? 1756. Okay, so
I'm going to use ADD 10 colon 19. And then I'm using logger hello from root. CTRL-D.
And we need to wait until we reach minute 19. So journalctl, uppercase G. Oh, and do
you see what is going on? We have a timing issue. So it's 2219. What did I do in my ADD
prompt? In my ADD prompt, I went for 1019. Yeah, 1019, 10 p.m. I can understand that.
But for ADD, that doesn't really work. So let's give it a second try. We are now 2220.
So I'm going to use ADD 22 colon 21. Logger another try. CTRL-D. So what time is now?
Well, again, we need to wait for 45 seconds. So the wait is over once more. Let's use journalctl
and uppercase G. And there we can see that it worked. Also, ADD Q is showing everything
that is in the ADD Q. And kind of funny, we do have a scheduled job for 1019 tomorrow.
That's because of the 1019 specification. I could have used 1019 p.m., most likely.
So if I would use ADD 10 colon 25 p.m., then you can see that it will be executed at 2225
and echo. No, not echo, because we don't have a standard out. Logger hello would do it.
And CTRL-D. And there, ADD Q is showing everything that is currently scheduled for running. And
if you don't want to run it anymore, well, ADD RM will remove it. So now I have removed
ADD job number one. And that's how you can use ADD.