AmiCron - Cron task for the Amiga

This is a rather crude but effective version of the Unix (tm) 
program known as "cron" modified to run on an Amiga.  For those 
who aren't Unix knowledgeable, cron is a background task which 
uses a disk-resident table to automatically run certain tasks on a 
regular basis.  The cron table's format is very simple...it 
contains entries in the form of lines where each line has 6 fields 
and each field is separated by "white space" (either tabs or 
spaces) from it's neighbor. The fields are as follows:

   1.  Minute       (0-59)
   2.  Hour         (0-23)
   3.  Day          (1-31)
   4.  Month        (1-12)
   5.  Day of week  (0-6 where 0=Sunday and 6=Saturday)
   6.  Command      This is the command to be run at the appointed 
                    time.  It will be run just as if typed into 
                    the CLI.

Each of the first 5 fields are numbers.  However, it is 
permissable to use an asterisk (*) in a field to mean ALL possible 
numbers for that field,  and you can specify a series of numbers 
separated by commas (,) and ranges separated by dashes (-).  For 
instance, in the Day field you could specify "1,5,10" to mean the 
first, fifth, and tenth days of the month; or you could specify 
"1-15" to mean the first through the fifteenth of the month.  Here 
are some examples of Amicron table entries:

  	Print the date in the crontask window every minute:
  		* * * * * date
  
  	Print the date in the crontask window on the hour, every hour:
  		0 * * * * date
  
  	Run uupc at 4:30 am every day except Sat and Sun:
  		30 4 * * 1-5 uupc -siscuva
  
  	Incrementally backup the files every other day at 7:30 pm:
  		30 19 * * 1,3,5 sdbackup -l -s LAST dh0: incbkup_1:

    Backup the files on the 1st and 15th of each month at 1:00 am:
        00 01 1,15 * * sdbackup -l dh0: SemiBkup_1:

The Amicron table file is located using the following path:
    sys:usr/spool/cron/crontab
and errors, if any are logged into the following path:
    sys:usr/spool/cron/cronerr

Crontab entries *MUST* be left justified starting in column 1 and 
each entry must contain 6 fields, each separated by spaces or 
tabs.

To run Amicron, you must first set up the directory 
"sys:usr/spool/cron" and then use your favorite editor to create 
the "crontab" file.  Amicron needs a CLI window for displaying the 
output of the commands it runs...but it can be made as small or 
large as you wish.  Assuming that you have placed Amicron in your 
command directory (c:), you can start it by typing the following 
line into a "newcli" window:
    Amicron
Then you can size and move the window anywhere you want, just be 
sure not to type anything else into the window because that would 
prevent cron tasks from running.

I have an entry in my startup-sequence file that looks like this:
   run newcli con:0/140/160/50/CronTask s:startcron
The "s:startcron" file contains one line:
   Amicron
This automatically sets up a tiny CronTask window and runs Amicron 
in it.

This program was originally written by Steve R.  Sampson (UUCP:
sys1!killer!sampson), who very kindly responded to my request for
a PD cron that I could port to Minix.  I haven't done that yet
(My new Amiga 2000 came in right after I received the cron
program <grin>) but will do so ASAP.  The modifications to make
it run on the Amiga were very minor!

Rick Schaeffer          UUCP:  seismo!uunet!iscuva!ricks
E. 13611 26th Ave.      Phone: (509)928-3533
Spokane, WA  99216