[plug] Crontab??

[Bernd Felsche]

On Tuesday 27 July 2004 19:40, Senectus . wrote:
> I have various jobs that I want to start and stop at particular times.
> I've tried all sorts of things but I've never seem to be able to get
> crontab to do what I want it to do, when I want it...

Try setting the system clock correctly. :-)

> I've read man files (not much use), and various howto's etc.. and
> none of them seem to make any sense.. does anyone know of a decent
> tutorial for crontab?

Which cron?

Paul Vixie's works at several levels: system and user.

Individual users may be permitted to set up their personal crontab.
Anything in them gets run with the privileges of its owner. Such
crontabs are maintained by the use of the "crontab" command.

System-wise; /etc/crontab controls most of cron's behaviour. Your
system may have /etc/cron.{hourly,daily,weekly,monthly} directories
that hold *programs* based on that default schedule.

Then there's /etc/cron.d which contains application/package
crontabs. A nice feature, if you don't get trapped by it, is that
application crontabs can be "suspended" by renaming them as only
those with name consisting solely of upper- and lower-case letters,
digits, underscores, and hyphens are valid.  So renaming to
something with a dot in the name is convenient.

The crontab file has one of two formats, depending on being user- or
system-crontab. The latter adds a "user" field to each command; for
the userid to be used to run the corresponding command.

The cron daemon will notice if a crontab changes and reload its
internal idea of what to do next.

-- 
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
\ /  ASCII ribbon campaign | I'm a .signature virus!
 X   against HTML mail     | Copy me into your ~/.signature
/ \  and postings          | to help me spread!