unexpected behavior in 'date(1)'

[Diffenderfer, Randy]

Folks:

Here's a cute one for you.  This is being done on a RedHat 7.3 w/ patches,
i386 system. 'uname -a' gives:
Linux ahmler1.mail.eds.com 2.4.20-20.7smp #1 SMP Mon Aug 18 14:46:14 EDT
2003 i686 unknown

Normal behavior:

$ date
Fri Apr 23 12:37:15 EDT 2004
$ date --date=yesterday
Thu Apr 22 12:37:19 EDT 2004

No surprise.  However, go back in time to the day after the spring daylight
savings time adjustment.
Now we see something like...

$ date
Mon Apr 5 00:05:00 EDT 2004
$ date --date=yesterday
Sat Apr 3 23:05:00 EST 2004

Surprise!

Note:  I haven't jimmied around a system to actually reproduce this.  This
is my surmise for the symptoms I have seen when a script that fired after
midnight to do maintenance on "yesterday's" files produced anomalous
results.  The machines I have in other parts of the world (Germany and
England for example did this on 29March) reacted in a similar fashion on
their changeover dates.

Bottom line?  Time to put all these boxes on GMT and be done with this
daylight savings nonsense! :-)

Randy Diffenderfer