[SOLVED] Cron job not scheduling

smilemukul · 01-09-2011, 10:59 AM

I have a cron job to schedule the task on the third sunday of the month.I saw the previous threads but didn't find any solution.

How the cron syntax can be written.

Any response will be appreciated.

Thanks

Tinkster · 01-09-2011, 11:09 AM

man crontab

Cheers,
Tink

smilemukul · 01-09-2011, 11:23 AM

No information is found in man

Thanks

repo · 01-09-2011, 11:26 AM

What info do you need?
http://en.wikipedia.org/wiki/Cron
http://adminschoice.com/crontab-quick-reference

Kind regards

Tinkster · 01-09-2011, 11:29 AM

Quote:

Originally Posted by smilemukul

No information is found in man

Thanks

Which distro are you using that it shouldn't provide a man
page for one of the most basic tools out there?!

Just so I can point other new linux users at this thread and
tell them to avoid that distro.

Cheers,
Tink

colucix · 01-09-2011, 11:42 AM

The section 5 of the manual provides information about the crontab's syntax:

Code:

man 5 crontab

Anyway it will suggest how to run a cron job every sunday. Then you have to add an extra check for the day of the month, that has to be ≥ 15 and ≤ 21. You can add a conditional expression in the crontab entry itself or at the beginning of the script.

networking.dept · 01-09-2011, 11:58 AM

Hello,

Cron format is like below :-

Min Hour DOM MON DOW <script-or-command>

But By googling for some time i have found some interesting

Below scenario taken from :- http://hintsforums.macworld.com/arch...p/t-25110.html

0 4 15-21 * 0 /path/to/my/command

[Just so everybody's clear, the reason for 15-21 is that the third Sunday is always one of those dates, and no other Sunday (2nd, 4th) can ever be those dates. ]

Hope this helps you.

colucix · 01-09-2011, 12:21 PM

Quote:

Originally Posted by networking.dept

0 4 15-21 * 0 /path/to/my/command

Nope. This will not work as intended. The two day fields (day of the month and day of the week) in a crontab entry add up: this means the suggested line will run every day between 15th and 21st plus every sunday. The man page (section 5) of crontab clearly states that. This is why I suggested an explicit check for the day of the month in my previous post.

networking.dept · 01-11-2011, 12:27 AM

@colucix, I am explaining cron which i have written and i have taken that cron from some other forum i have already posted Link :-

0 4 15-21 * 0 /path/to/my/command

On Every Minute of 4th Hour on sunday which comes into between 15-21 date every month it will run script.

And as already mentioned there will be only 1 sunday between 15-21 date.

As per my assumption it will work.

ashish_neekhra · 01-11-2011, 01:00 AM

You can check out here ...

colucix · 01-11-2011, 01:04 AM

Quote:

Originally Posted by networking.dept

As per my assumption it will work.

Try it and tell me the results on Sunday, 23rd!

Taking a solution from another forum does not necessarily mean it's correct even if they claim it works. Anyway, as clearly stated by the crontab man page:

Quote:

Note: The day of a command's execution can be specified by two fields — day of month, and day of week. If both fields are restricted (ie, aren't *), the command will be run when either field matches the current time. For example, ``30 4 1,15 * 5'' would cause a command to be run at 4:30 am on the 1st and 15th of each month, plus every Friday.

You can easily try that. Suppose now is 08:00 AM on January, 11st (Tuesday). You can set a cron job like this:

Code:

5 8 15-21 * 2 date >> $HOME/cron.log

and see if it runs. Practice is more helpful than theory!

smilemukul · 01-12-2011, 03:45 PM

Can anyone provide me the syntax for the cronjob which should execute on 3rd sunday.

Thanks

colucix · 01-12-2011, 03:56 PM

You could at least show some effort and post what you've tried so far. Have you read the suggested documentation? Have you understood advices in post #6? Have you followed the further discussion? What are your shell scripting skills?

smilemukul · 01-18-2011, 03:59 PM

Can any one tell me what the below expression means while creating a script as,

[`date +%a` = Sun ]

Also need to confirm whether below command is correct for running a cron job for 3rd Sunday as,

0 0 15-21 * * [`date +%a` = Sun ] && /path/to/command

Thanks

smilemukul · 01-19-2011, 03:41 AM

Any response will be appreciated.

Thanks