How to install and use at job scheduling?

Question

I am not clear on the following:
Is the process for at available to all linux installations? Or do would I need to do something to "install" it?

Answer 1

Depending on your Linux distribution and the kind of installation (minimal, desktop-centric, etc.) at (and atd the at job scheduler daemon) is installed by default or not.

To verify it you can issue commands like:

$ which at
/usr/bin/at
$ which atd
/usr/bin/atd
$ yum whatprovides atd # to get the package name 
$ yum info pkg-name # to see if it is installed

(assuming yum is available on Suse - using a Fedora system here)

If the package is not installed you can install it via your package manager, e.g. something like:

$ yum install at # on fedora at least

If it is installed, perhaps the daemon is not started on bootup by default.

To see if it running:

$ pgrep -l atd

Or just test it like this

$ echo echo hello world | at now

(watch your system logs in another terminal and/or check your local mailbox)

How to start it depends on your init-system, if it is old-school it would be something like:

$ /etc/init.d/atd start

If it is systemd it would be something like:

$ systemctl start atd

For a init.d based system as well for the systemd one there are also commands to display the status of a service like atd and to make it startup on boot.

But most likely atd is started by default after installation and it is setup by default to be started at system boot.

Answer 2

Essential on most systems, is a daemon, usually atd