Is there a way to schedule a cron job that does not run on the 3rd weekend of the month?

Question

Any ideas, anyone?

Answer 1

Run it on the 1st, 2nd, 4th (and maybe 5th, it can happen) weekends.

# m h dom      mon dow   command
  * * 1-20,28-31 *   0     echo #test

I have no idea if that will run everyday, or just on Sundays (day 0), but it won't run on the 21st to 27th - the third week. It may be simple enough to put a check in the script that will exit if it is the third week (or it's not a Sunday).

Answer 2

If you want it to run on any possible Saturday except the third one (try #3):

GREP=/usr/local/bin/grep
TODAY=/bin/date "+%d"
THIRD_SAT=/bin/date -v1d -v+1m -v-7d -v-sat "+%d"
#min hr day month weekday script
0    0  *   *     6       ($THIRD_SAT | $GREP $TODAY) || /bin/echo doit

Answer 3

1. make a cron job that runs a given script when needed ignoring the 3rd weekend part
2. make a cron job that runs on the 21 and another on the 28 to switch the script out and back for another no-op script.

Hacky but it would work

Answer 4

Save the following as /usr/local/bin/is_third_week_in_month.sh or some place

#!/bin/bash

if [ $# != 3 ]
then
    echo "Usage: $0 <yyyy> <mm> <dd>" 1>&2
    exit 127
fi

YEAR=$1
MONTH=$2
DAY=$3

FIRST_WEEK_IN_MONTH=`date +%V -d $YEAR-$MONTH-01`
WEEK_FOR_DAY=`date +%V -d $YEAR-$MONTH-$DAY`

DIFF=$(($WEEK_FOR_DAY - $FIRST_WEEK_IN_MONTH))

if [ $DIFF = 2 ]
then
    # this is the third week
    exit 0
else
    exit 1
fi

and then add to crontab

12 00 * * 1,2,3,4,5  your_command
12 00 * * 6,7  test ! /usr/local/bin/is_third_week_in_month.sh `date "+%Y %m %d"` && your_command

Or you could modify the script to check for date as well if you want to only have one line in crontab.