Python and cron jobs.
staschuk at telusplanet.net
Wed Aug 6 00:27:22 CEST 2003
> Actually, I think I will open the crontab file as a file and do the
> changes that way because this would also involve in the deletion of
> some cronjobs. [...]
Note that you can invoke the crontab so as to print out a given
crontab -u username -l
Using the os.popen family, you can then read the output as a file,
modify it, then write it back as the stdin for an invocation of
crontab -u username
This is perhaps slightly more work than simply manipulating the
file in /var/cron/tabs directly; certainly it is less efficient,
though I doubt that's much of a concern for this task. The
advantage is that it allows for the possibility that the local
system has some strange way of storing crontabs, a way which
crontab(1) understands but your program should not need to.
> [...] I just wish to know how to get the cron deamon to
> reload the crontab. Are you certain that it checks for changes or
> reloads every minute?
No. There's lots of cron implementations, and I certainly haven't
used all of them; perhaps some need a SIGHUP to reload, for
example. Check your local documentation to be sure, 'man 8 cron'
or what have you, and/or just try it as Michael suggested.
Steven Taschuk staschuk at telusplanet.net
"I tried to be pleasant and accommodating, but my head
began to hurt from his banality." -- _Seven_ (1996)
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