UNIX for Dummies Questions & Answers

Hello All,

I have three requirements to schedule three shell scripts in crontab.
Could you please help me in this:
1) To schedule a shell script every 5mins interval every day between 10PM to 10:30PM
2) To schedule a shell script every 10min interval every day between 9AM to 10AM.
3) To schedule a shell script every day 10min interval every day between 7:30AM to 8:30AM.

Thanks in advcance.

Hello abhi_123,

Following may help you. (Not tested though)


00-30/5 22 * * * /test/singh/test.ksh



*/10 9-10 * * * /test/singh/test.ksh



30/10 7-8 * * * /test/singh/test.ksh



Thanks,
R. Singh

Thanks a lot R.Singh.

Could you also please explain me the below meaning:
1) 00-30/5 22 --> 30divided by 5? and 22 means..?
2) 30/10 ?
Thanks again.

Hello abhi_123,

Following may help you in same, also you can get more information from man cron too.

1st: 00-30/5 22 * * * /test/singh/test.ksh22 shows script should run from 10:00 PM 00-30to 10:30 PM within every 5 mins. Here /5 shows every 5 mins.

2nd: */10 9-10 * * * /test/singh/test.ksh 9-10 shows from 09:00 AM to 10:00 AM, */10 means every 10 mins.

3rd: 30/10 7-8 * * * /test/singh/test.ksh 7-8 shows fr 07:00 AM to 08:00 AM, 30/10 means starts from 30th min and run every 10 mins.

Hope this helps.

Thanks,
R. Singh

Note that not all OSs support using / (AIX springs to mind). In that case you'll need to specify all the possible values in a list, e.g.

Code:

00,05,10,15,20,25,30 22 * * * test.ksh

Some of RavinderSingh13's suggestions would work on some Linux and UNIX systems, but would not work on others; some would be accepted by some system, but would not trigger at the requested times. The following should work with any version of cron assuming that when you say between you mean to include the end points:If you don't want to include the end points:

As always with cron scripts: watch out for Cron Problem Number One.

In addition i strongly suggest to add redirections to your crontab entries:

Code:

0,5,10,15,20,25,30 22 * * * /path/to/your/script >/dev/null 2>/dev/null

Otherwise whatever your script produces as output would be sent to you via mail. If you want to preserve any output replace /dev/null with the name of a log file but never have any entry without such a redirection.

I hope this helps.

bakunin

/PS: i prefer using this style of redirection because it is not dependent on order. The following to lines do the same:

Code:

0,5,10,15,20,25,30 22 * * * /path/to/your/script 1>/dev/null 2>/dev/null
0,5,10,15,20,25,30 22 * * * /path/to/your/script 2>/dev/null 1>/dev/null

whereas these two lines produce different results:

Code:

0,5,10,15,20,25,30 22 * * * /path/to/your/script >/dev/null 2>&1
0,5,10,15,20,25,30 22 * * * /path/to/your/script 2>&1 >/dev/null

bakunin