Re: Cron, > 1 month but < 2 months

[vogelke+debian@pobox.com (Karl Vogel)]

>> On Sun, 11 Mar 2012 01:42:25 -0600, Christofer C. Bell wrote:

C> According to this page[1], the following works for that:
C>    * * */45 * * your_scheduled_task
C> I've not tried it myself.

   I'd use a timestamp file in conjunction with find; what happens when
   your 45-day interval crosses Jan 1st?  For example:

     me% date
     Sun Mar 11 21:51:21 EDT 2012

     me% touch -d '45 days ago' timestamp

     me% ls -l --time-style='+%d-%b-%Y %T' timestamp
     -rw-r--r-- 1 me   me   0 26-Jan-2012 20:51:27 timestamp

     me% find timestamp -daystart -mtime +1 -print
     timestamp

     me% find timestamp -daystart -mtime +44 -print
     timestamp

     me% find timestamp -daystart -mtime +45 -print     # no output


   Run something like this every day:

     #!/bin/bash
     ts=/time/stamp/file
     interval=45

     set X $(find $ts -daystart -mtime +$interval -print)
     shift
     case "$#" in
         0) logger 'starting' ;;
         *) logger 'skipping'; exit 0 ;;
     esac

     # run your php script or whatever ...
     touch $ts


   Another advantage: you can decide whether to "touch $ts" based on the
   return code from whatever you're trying to run.  If it fails, do you
   want to alert someone and run it tomorrow or wait another 45 days?
   Reschedule by setting the $ts modtime instead of dorking around with cron.

-- 
Karl Vogel                      I don't speak for the USAF or my company

Bumper-sticker on Mel Gibson's car: "Swerve If You Love Jesus"