crontab question involving cvsup
viktorlazlo at telus.net
Sat Aug 28 13:04:55 PDT 2004
On Thu, 26 Aug 2004, Joshua Tinnin wrote:
> > >>man cron gives:
> > >>
> > >>crontab [-u user] file
> > >>
> > >>'file' being the important part, methinks. ;)
> > >
> > >I'm not sure what you mean ... If you're wondering, I'm using the
> > > main crontab file (/etc/crontab), as right now there's no need for
> > > me to use multiple ones.
> > Just an aside, but a rather important one: /etc/crontab is the
> > *system* crontab and shouldn't have your jobs in it. It may in fact
> > be this issue that is causing the problem, but I've not looked into
> > it enough to say unequivocally...
> I don't think this is true. For one thing, as suggested, directing
> output of cvsup to /dev/null worked, and now my cron job is working.
> Another is that neither the handbook nor the /etc/crontab file itself
> warn about editing it. In fact, the handbook section 11.6 says,
> "Important: You must not use the procedure described here to
> edit/install the system crontab. Simply use your favorite editor: the
> cron utility will notice that the file has changed and immediately
> begin using the updated version." This is what I did. I didn't use the
> crontab command to edit/install it, I just used an editor.
> > Since your job needs root privileges, you should put this in root's
> > crontab, either by su'ing to root and running "crontab -e" at the
> > prompt, or if you have sudo installed, "sudo crontab -e" will get you
> > there.
> > Unlike the system crontab, user crontabs, including root's, are
> > under /var/cron; the file format is slightly different, and misuse
> > of the system crontab for regular jobs is the cause of several
> > FAQ posts we see here every few months or so; one of these goes
> > something like, "why do I get an email from cron saying it can't
> > complete my job, unknown user, etc. ??"....
> Again, I see nothing in the documentation warning against editing the
> system crontab file, only that it can't be installed/edited with the
> crontab command.
The main danger in using /etc/crontab is that it can easily be wiped out
during system updates, while user crontabs will not be affected.
/etc/crontab does also use a slightly different format from user crontabs,
which you need to be aware of if transferring entries between them.
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