[Smaug] A quick scripting puzzle

[Peter Belew]

Among the commands various people (including myself) have
used, 'cal' and 'colrm' are BSD in origin. 'cal' seems to be
universal (UNIX-versal?) anyway, but apparently some solari don't
have 'colrm'. On Linux (Fedora Core 1 on this system):

HISTORY
     The colrm command appeared in 3.0BSD.

Hmm ... cal in Linux has a BSD heritage, but apparently there's
an earlier cal from AT&T:

HISTORY
     A cal command appeared in Version 6 AT&T UNIX.

'colrm' does not exist on  SCO UNIX 5.0.6 (deepthought.armory.com);
the same system's 'cal' claims to be standards-compliant.

My algorithm does work on deepthought, though. My favorite
test is like

 for x in 1 2 3 4 5 6 7 8 9 10 11 12; do
> LAST=`cal $x 1752 | rest-of-my-algorithm`
> echo $x - $LAST;
> done

After which I do 'cal 1752' to compare the dates calculated with
the whole calendar for that year (worst-case test).

- Peter

On 11/19/05, Anthony Ettinger <apwebdesign at yahoo.com> wrote:
> gcal isn't standard
>
> --- Thomas Leavitt <thomas at thomasleavitt.org> wrote:
>
> > On Fri, 2005-11-18 at 08:43 -0800,
> > smaug-request at lists.svlug.org wrote:
> > > Message: 2
> > > Date: Thu, 17 Nov 2005 20:26:33 -0800
> > > From: Peter Belew <peterbe at sonic.net>
> > > Subject: [Smaug] A quick scripting puzzle
> > > To: SMAUG Users <smaug at lists.svlug.org>
> > > Message-ID: <20051118042633.GA6844 at sonic.net>
> > > Content-Type: text/plain; charset=us-ascii
> > >
> > > For amusement, create a 1-line sh or bash command
> > which will set
> > > a shell variable $LASTSUNDAY to the date (2-digit
> > day) of the last
> > > Sunday in the current month.
> > >
> > > Like
> > >
> > >    LASTSUNDAY=`some_shell_stuff`
> > >
> > > Use only standard Unix utilities such as 'cat' or
> > 'head' or 'date'.
> > >
> > > The command shouldn't take longer than an
> > 80-character line.
> > >
> > > (I did this myself for creating a cron job which
> > sends out email
> > > announcing a meeting on the last sunday of a
> > month).
> > >
> > > :)
> > >
> > >  Peter
> > >
> >
> > Here's my entry... I'm pretty sure, somewhere within
> > the byzantine array
> > of options available in gcal, there's a way to
> > directly produce this...
> > but I couldn't find it. However, this works, no
> > matter whether there are
> > four or five Sundays in a month.
> >
> > LASTSUNDAY=`gcal -i -s1|tail -n1|sed "s/[
> > ]*$//"|rev|cut -b-2|rev`
> >
> > I'm not sure how this works, but you could probably
> > cheat more, by
> > feeding gcal instructions to use some of these
> > commands from a file...
> >
> > and of course, I'm cheating, by using gcal, but hey.
> > :)
> >
> > Thomas
> >
> >
> >
> > _______________________________________________
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> > http://lists.svlug.org/lists/listinfo/smaug
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> >
>
>
> Anthony Ettinger
> ph: (408) 656-2473
> web: http://www.apwebdesign.com
>
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