Cron to run every 2nd wednesday?

Question

I need to find a way to cron a job so that it runs every second wednesday of the month. Is this possible?

Answer 1

My manpage for crontab (which I sadly can't seem to find online) gives the following example:

# Run on every second Saturday of the month
0 4 8-14 * *    test $(date +%u) -eq 6 && echo "2nd Saturday"

Adapting this to your purposes...

0 4 8-14 * *    test $(date +%u) -eq 3 && job.sh

Answer 2

It's not possible using cron on its own, but you could call a script once a week that does the test:

In crontab, run second_wed.sh at 12.00 every Wednesday:

0 12 * * 3 /home/you/bin/second_wed.sh

In second_wed.sh:

#!/usr/bin/env bash
day_of_month=`date +"%
if [ $day_of_month -gt 7 -a $day_of_month -lt 15 ]; then
  # Call your program here instead of 'ls'…
  ls
fi

Answer 3

Based on this answer, you could do:

00 12 * * Wed expr `date +\%d` \> 7 \& `date +\%d` \< 15 >/dev/null && runJob.sh