Q. I get sunrise and sunset reversed when I add my own arguments.

A. "longitude is positive East"

   +42 -71 -5 is Boston, MA, EST.
   +40 +86 -5 is south of Shihazi, China, with times interpreted as EST.
 
   The sun does in fact set in China about the time it rises here.
 
   I'm guessing that you actually wanted +40 -86 -5.  That's somewhere
   in Indiana, right?  The result is more reasonable:
 
   Lat 40.520000, Long -86.519997, timezone -5.000000
   Year 1999, Month 10, Day 11
   Sunrise at 07:52 at 098 degrees
   Sunset at 19:12 at 261 degrees
 
   You're on the extreme western edge of the Eastern timezone, and
   I'm on the extreme eastern edge, so the fact that the sun sets
   over an hour later there is about right:
 
   Lat 42.377834, Long -71.106323, timezone -5.000000
   Year 1999, Month 10, Day 11
   Sunrise at 06:52 at 099 degrees
   Sunset at 18:08 at 261 degrees
 
   One bug that I do know of is that I should be asking for timezone
   instead of UTC offset.  That result for 40.52 -86.52 above is
   wrong since it's correcting for DST because my locale uses DST,
   but Indiana doesn't, right?  What an enlightened state: I hate
   DST.  You should get the right answer on your machine: 6:52 & 18:12.
 
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Q. I can't see where to add the x10 events into your program.

A. They go in a crontab file, x10events rewrites crontab files.

   What I did was to create an x10 user.  I made sure that they had
   adequate permissions to run heyu:

      # grep x10 /etc/passwd
      x10:*:100:14:Nobody:/:/bin/sh
      # grep x10 /etc/group
      uucp::14:uucp,x10
      # ls -l /dev/ttyS0
      crw-rw-r--   1 root     uucp       4,  64 Nov  2 06:16 /dev/ttyS0

   and then, as root, did a `crontab -e -u x10` to edit their crontab.
   This is where I put all the x10 events.
   
   In this way, x10 events are in a separate file from all other
   cron entries.  This makes the x10events code simpler and reduces
   the probability that a bug in x10events will stomp on some other
   crontab entry.
   
   OK.  Then you put x10events.sh in /etc/cron.daily,  It does this:
   
      /usr/bin/crontab -u x10 -l \
        | /usr/local/bin/x10events 42.3778343 -71.1063232 -5 \
        > /tmp/x10.crontab
   
      /usr/bin/crontab -u x10 /tmp/x10.crontab
      
      rm /tmp/x10.crontab 
   
   'crontab -u x10 -l' fetchs x10's crontab file.  'x10events...'
   rewrites it to standard out and '> /tmp/x10.crontab' dumps it to
   a tmp file.  'crontab -u x10 /tmp/x10.crontab' replaces x10's
   crontab file with the temp file.  The 'rm' cleans up the temp
   file.
   
   If you want to edit the comments or the x10 commands, you just
   run 'crontab -e -u x10` as root again.  x10events will pick up
   the changes on the next run of cron.daily, or you can run
   x10events.sh by hand.
   
   I suppose the functionality of x10events.sh could be incorporated
   into the executable: that would be less complex, but it would also
   less flexible.
   
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Q. Why do you express timezones East of UTC as negative, that's wrong.

A. ISO8601 doesn't agree: ftp://elsie.nci.nih.gov/pub/iso8601.ps.gz

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Q. x10events dumps core on my redhat 7.0 box.

A. Sorry, but I don't have redhat 7.0, so I haven't been able to debug
   this.  It seems to work under 7.1 and 7.2, and I remember hearing
   people complain about a biggy gcc in 7.0, so maybe you should
   upgrade.

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