Path: utzoo!mnetor!uunet!steinmetz!ge-dab!codas!killer!jfh
From: jfh@killer.UUCP (John Haugh)
Newsgroups: comp.unix.questions
Subject: Re: Cron
Message-ID: <3000@killer.UUCP>
Date: 20 Jan 88 18:37:12 GMT
References: <11098@brl-adm.ARPA> <449@wa3wbu.UUCP> <1988Jan17.235014.19530@lsuc.uucp>
Organization: Big "D" Home for Wayward Hackers
Lines: 36
Summary: New/Old cron.

In article <1988Jan17.235014.19530@lsuc.uucp>, dave@lsuc.uucp (David Sherman) writes:
> In article <449@wa3wbu.UUCP> john@wa3wbu.UUCP (John Gayman) writes:
> >					At different times here,
> >if I make a change in the cron time-table, I do not re-boot the whole
> >machine. I simply kill the current cron job process and start it again
> >from the console. The time/jobs are read in at execution time.
> 
> Every cron that I have ever seen or heard of either rereads crontab
> every minute or so (v6 may have done this) or checks its modification
> time and rereads it when it changes.  I would consider a cron that
> has to be killed off and restarted when you change crontab to be
> seriously brain-damaged.  Perhaps you should check whether your
> supposition is really correct.
> 
> David Sherman

In the OLD cron's, the crontab was read in at invocation time, and checked
every minute to see if it changed.  Looking at /usr/adm/cronlog (or whatever
yours is named) would tell you when the crontab was read.

The NEW cron's have individual crontabs for each (potential) user.  Editing
one of those files will not update cron's idea of what is going on.  You
must use the crontab command (with -l option) to get a copy of the crontab
(or you can just copy it from /usr/spool/cron/crontabs/<what-ever>) and
then put it back using the crontab command again.

Does that answer the question completely?  I suggest you drag out the
manuals and see what other commands the cron entry refers you to and give
all of them a read.

- John.
-- 
John F. Haugh II                  SNAIL:  HECI Exploration Co. Inc.
UUCP: ...!ihnp4!killer!jfh                11910 Greenville Ave, Suite 600
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 ... Then Buy One!"                       (214) 231-0993 Ext 260