Cron job ,every other monday

Question

hello
i would like to schedule a cron job every other monday
-- OS info
[oracle@dev3 ~]$ uname -a
Linux dev3.pcst3.net 2.6.18-194.17.1.0.1.el5 #1 SMP Wed Sep 29 15:57:39 EDT 2010 x86_64 x86_64 x86_64 GNU/Linuxhere is what i have in for cron job , yes this shows every monday but i am looking for every other monday,it ran today(03/26),next runs should be 04/09 and 04/23 ....
# Bi-weekly report
30 11 * * 1 /u01/scripts/monday_query.sh > /u01/scripts/monday_query.log 2>&1here is what we have in monday_query.sh
#!/bin/ksh
# set -xv
. dbbash_profile
export ut=/u01/scripts/ut
export pass=`grep -i ls011 $ut/pwdfile | awk -F":" '{ print $2 }'`
sqlplus  ls011/${pass} < /u01/scripts/monday_query.shany help is much appreciated to make this run every other monday
Please help

Answer 1

From the cron man page: http://unixhelp.ed.ac.uk/CGI/man-cgi?crontab+5
"Step values can be used in conjunction with ranges. Following a range
with ``/<number>'' specifies skips of the number's value through the
range. For example, ``0-23/2'' can be used in the hours field to spec-
ify command execution every other hour (the alternative in the V7 stan-
dard is ``0,2,4,6,8,10,12,14,16,18,20,22''). Steps are also permitted
after an asterisk, so if you want to say ``every two hours'', just use
``*/2''."
Or, create a flag file with 'touch ran_cron_job_last_monday' after a Monday that you ran the script.
Then throw a condition into your script to check for the file. If the file exists, remove it. If the file doesn't exist, then run your script and when finished, create the file again.
For example:
#! /bin/ksh
if [ -e ran_cron_job_last_monday ] ; then
rm -f ran_cron_job_last_monday
else
touch ran_cron_job_last_monday
exit 0
fi
... do here what your script is supposed to do ....
exit 0