Difference between revisions of "Cron with Unix or Linux"

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Note: You are currently viewing documentation for Moodle 3.1. Up-to-date documentation for the latest stable version of Moodle is probably available here: Cron with Unix or Linux.

(The command line (cli) cron)
(Method 1: The command line (cli) cron)
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(substitute the correct path to moodle and for php as required)
 
(substitute the correct path to moodle and for php as required)
  
You can simply type this on the command line this to see if it works. If you are not sure about the path to PHP you can type <code>which php</code>.
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You can simply type this on the command line this to see if it works. If you are not sure about the path to PHP you can type "<code>which php</code>".
  
 
'''NOTE:''' This path is different to that used in Moodle 1.9 and earlier. If you are upgrading from 1.9 you will need to change your cron script path.
 
'''NOTE:''' This path is different to that used in Moodle 1.9 and earlier. If you are upgrading from 1.9 you will need to change your cron script path.

Revision as of 16:58, 16 May 2012

Template:Cron On Unix and Linux use the built in cron program which is standard on nearly all systems. You are required to add a command to the 'crontab' (the table that holds cron commands) for the web server user.

There are two different methods that can be used to invoke the Moodle cron process:

NOTE: The commands shown need to be added to the crontab to function (described in a moment). However, you can - and should - run them on the command line to check they work first.

Method 1: The command line (cli) cron

If you have the PHP CLI version installed then this is the recommended method of invoking cron. The correct command is as follows...

/usr/bin/php /path/to/moodle/admin/cli/cron.php

(substitute the correct path to moodle and for php as required)

You can simply type this on the command line this to see if it works. If you are not sure about the path to PHP you can type "
which php
".

NOTE: This path is different to that used in Moodle 1.9 and earlier. If you are upgrading from 1.9 you will need to change your cron script path.

Tip:: If you have problems, see the PHP page. In particular, suspect an alternate php.ini for the CLI PHP command which may not have suitable settings.

Web based cron

NOTE: In order to use the web based cron script you must first check Cron settings to make sure this method is permitted.

The idea is to call the following web page (you can try this from your browser):

http://url.of.your/moodle/admin/cron.php

A command line (text based) browser is needed to run this from the server. Possibilities are as follows (OSX, for example, only ships with curl)...

/usr/bin/wget -q -O /dev/null/ http://url.of.your/moodle/admin/cron.php

(no output is displayed - remove the -O /dev/null/ to test)

...OR...

/usr/bin/curl http://url.of.your/moodle/admin/cron.php -o /dev/null/ -silent

(no output is displayed - remove the -o /dev/null/ -silent to test)

Using the crontab program on Unix/Linux

Once you have selected (and tested!) an appropriate command to invoke the Moodle cron it must be added to the web users 'crontab' to schedule it to run regularly. Use the following command (as root) substituting the correct user in place of 'www-data' (e.g. 'apache' for Centos, 'www-data' for Debian/Ubuntu - Google will know!)

# crontab -u www-data -e

This will bring up an editor window (the first time it may ask you which editor to use). Add the command onto the end of the file in this way (it may be empty or it may have some instructional comments):

 */15 * * * *        /usr/bin/php /path/to/moodle/admin/cli/cron.php

The first five entries specify the times, followed by the command, to run. This says to run the command every 15 minutes which is normally ok. In some cases you may wish to run it more often. On a hosted system you may get complaints if you do not run it a lot less often (e.g. to run every two hours use '0 */2 * * *' for the first five entries). If you want to use the wget/curl version, the first five entries remain the same - just change the command part.

See also