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cron crontab /etc/default/crontab

vchown pcunix .! cron vchown pcunix .! crontab vchown pcunix .vchown pcunix .

From: Bela Lubkin <belal@sco.com>
Subject: Re: New /etc/default/cron from OSS642a - Cron supplement
Date: Tue, 17 Dec 2002 19:44:42 GMT
References: <fc5ef85a.0212160509.4e33e924@posting.google.com>
<20021216171623.GA10825@jpradley.jpr.com>
<fc5ef85a.0212170259.621d72f7@posting.google.com> 

alex stuart wrote:

> Jean-Pierre Radley <jpr@jpr.com> wrote in message news:<20021216171623.GA10825@jpradley.jpr.com>...
> > alex stuart typed (on Mon, Dec 16, 2002 at 05:09:58AM -0800):
> > | It appears that during the install of the oss642a patch, a new
> > | /etc/default/cron is installed.
> <snip> 
> > But /etc/default/cron describes the purpose of each of those
> > variables; which part of the text leaves you with "cannot
> > determine what they are for"?
> 
> Did it? I read only the lines that appeared to be shell envvar assignment
> statements. I'm sorry I can't recheck this: I lost my job yesterday and
> now don't have access to an OpenServer box.
> 
> /etc/default/cron appeared to have the same syntax as a shell script. It
> has lines like "OLDPARSING=YES" which appears to be an assignment; and
> comments are introduced with a "#". When I ran a shell script from cron,
> I could echo the PATH variable, set as above, but was unable to access
> the NOTESHELL, INPUT and OLDPARSING envvars (l.h.sides?). I did not notice
> a new man page distributed with the VOLS containing descriptions.

A new man page was not included, but comments were added to
/etc/default/cron, as JPR stated.  I just downloaded a fresh copy of
oss642a, extracted etc/default/cron from it, and here is an excerpt:
 #       NOTESHELL  - If set to YES, users submitting cron and at jobs are
  #                    notified if their login shell is different from the shell
  #                    that is used by cron to run jobs.

Setting this to NO turns off the annoying warning:

  "warning: commands will be executed using /bin/sh"

  #       INPUT      - If set to NO, the cron job input mechanism is disabled:
  #                    neither % nor \ are changed, removed, or otherwise treated
  #                    specially.
  #       OLDPARSING - If set to YES, \ and % in cron jobs are acted on in the
  #                    way they were up through OpenServer 5.0.6.

These control the parsing of lines in a crontab.  It is an attempt to
get control over an old feature that few people knew about, but which
caused trouble in some crontabs: '%' means `newline'.

There are three combinations:

  INPUT=YES, OLDPARSING=YES -- acts like cron in OSR506 and earlier.  If
  there are any '%' chars in a crontab command field, they are converted
  to newlines.  The command (everything before the first newline) is
  passed the rest as standard input.  So:

     * * * * * cat%foo%bar%

  means: ``every minute, run `cat`, passing as standard input a file
  with 2 lines containing the texts "foo" and "bar"''.

  =========================================================================

  INPUT=YES, OLDPARSING=NO (default configuration in OSR507 and oss642a)
  -- same, except now you can prevent the special interpretation of '%'
  chars with a backslash.  So:

    * * * * * echo foo%bar

  means: ``every minute, run `echo foo`, passing as stdin a file with
  one line containing "bar"''.  But:

    * * * * * echo foo\%bar

  means: ``every minute, run `echo foo%bar`''.

  NOTICE that this changes the meaning of '\' in existing crontabs.  To
  express a literal '\' you need two of them:

    * * * * * printf "This outputs\\ntwo lines."

  =========================================================================

  INPUT=NO, OLDPARSING=(ignored) -- characters '%' and '\' have no
  special meaning in crontab lines.  So:

    * * * * * echo foo%bar
    * * * * * echo foo\%bar

  means: ``every minute, run `echo foo%bar`'', and ``every minute, run
  `echo foo\%bar`''

>Bela<

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