UNIX for Dummies Questions & Answers

I am still not to hot on how to invoke this command.

How could I use it to say, execute a backup program I have written in perl at a certain time I can specify.

Again, any help greatly appreciated.

Imay not be clear on what you are asking but
you place your invocation command and all other specifications
(such as the filename of the program and any options or
switches) into an executable shellscript file, and then specify the
executable in an at command, such as...

at 2:30a < execthis

...where execthis is an executable shellscript you have created.
(Of course, the name execthis is arbitrary, and can be any
filename you choose.)

You can also enter it from the command line like...

$ at 1 am March 21
at> tar cvf ~/inprogress backup.tar
at> compress backup.tar
at> CTRL-d
warning: cmds will be executed with /bin/sh
job 976385752.a at Thu Mar 21 01:00:00 2002

thanks mate.

what I was asking was this

I have written a program in perl to backup certain files

I wanted to use the at command to set it off during the night while I am away from the machine.

I think from what you have posted that I get the gist of the syntax and what to do but if you think you could be more specific on what I have given you, then please feel free to give me more information.

many thanks

You can't get much more explicit than he already has...
Check the man page for at to see some more examples.

You may also want to look into cron.
check the man page for crontab.