I have a server running Linux operating system. I am trying to schedule a cron job to run a task every two weeks (Fortnight) in Tuesday at 9am. I can only manage to run the task manually by comment (if I don’t want to run the job for this week) and uncomment (if I want to run the job for this week) as following:
0 9 * * 2 root java -jar test.jar // will run
# 0 9 * * 2 root java -jar test.jar // will not run
I have attempted to use the following cron job:
0 9 * * 2 case $(($(date +\%s) / (60*60*24*7))) in *[02468]) root java -jar test.jar
But this cron script does not seem to work.
Any thought
I would try to execute at 4AM every one of two tuesdays :
0 4 * * 2 test $((10#$(date +\%W)\%2)) -eq 1 && execute_cmd
We first get week number with date and correct formatting, then the 'one time out of two' thing is done by using 'test' command.
'test' evaluates to true or false depending on a given expression, here, it evaluates whether $((10#$(date +\%W)\%2)) equals 1 (hence -eq 1), in other words it returns true if the week number is odd.
So this crontab will execute on odd weeks, on tuesday (2) at 4 AM (0 4).
More in-depth details here : https://serverfault.com/questions/633264/cronjob-run-every-two-weeks-on-saturday-starting-on-this-saturday