I thought I knew Cron.....

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December 9th, 2010, 03:30 AM

Northie

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I thought I knew Cron.....

....But then I saw this syntax:

Code:

*/10	*	*	*	* cmd/to/run

can anyone tell me what the */10 means in the minutes column?

More importantly, I'm trying to stop it attempting to send emails. at the moment I have

Code:

path/to/php path/to/script/to/run > path/to/log/file

BUt after my server updated it's version of plesk I'm now getting emails, can i do

Code:

path/to/php path/to/script/to/run > path/to/log/file >  /dev/null 2>&1

to prevent emails?

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December 9th, 2010, 07:55 AM

SimonJM

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I believe the */10 means every 10 minutes - at HH:10, HH:20, HH:30, etc.
If your script produces emails then redirecting output is not going to prevent the mails from being pushed out by the mailer program being used - even if you could do what you are trying (the double redirection).
If you don't want mails beign sent then just comment out (or remove) that entry from your crontab. Problem with that, of course, is if you want other things the script does. In that case you'll need to find the 'payload' within the script and comment that part out.

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December 9th, 2010, 05:09 PM

Doug G

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from man 5 crontab

Quote:

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 specify
command execution every other hour (the alternative in the V7 standard
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".

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I thought I knew Cron.....

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