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Cron Troubleshooting

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Like with any troubleshooting problem you need to collect evidence to discover the root cause.

Then you need to go through the quick checklist:

  1. Do you have proper line in crontab? There should be five fields before invocation of the script or program.

  2. Are there any errors in standard logs? Check the cron log, usually /var/log/cron.log or /var/log/messages for errors
  3. Are you using relative paths? If your cron job is executing a script of some kind, you must be sure to use only absolute paths inside that script.
  4. Does you script has executable permissions?  Please be sure the script in question is executable. In the case script is writing to a file or folder, they should better be writable.
  5. Was your command ever invoked? Test your entry in crontab by changing the command to something like: echo "this is a test" > somefile  or touch /tmp/test
    For example you can change your invocation line to:
     * * * * * /bin/echo "this is a test" >> /tmp/test`date +"%y%m%d_%H%M"`

    See if it creates files each minute. Then replace /bin/echo "this is a test" back with your command and see what happens.

  6. Is your command working at all? Sometimes the script was changes and now has errors that prevent its execution. Often your script makes some implicit assumptions about environment which do not hold in case of running from cron. You can check this situation in two steps:
  7. If your cron job is running as a regular user, is this user allowed to run cron jobs? If a user was not allowed to execute jobs when their crontab was last edited, just adding them to the allow list won't do anything. The user needs to re-edit their crontab after being added to cron.allow before their jobs will run.
  8. The "%" character is used as newline delimiter in cron commands. If you need to pass that character into a script, you need to escape it as "\%".
  9. Are there any dead.letters? cron usually sends mail when there's a problem; check your mail and also look for ~/dead.letter.

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Support Forum Topic problems with cron (1-1)


Hello, I am having problems with cron.
I am using this string to be launched jcron

php /home2/svaghine/public_html/pileperorologi/administrator/components/com_csvimproved/helpers/cron.php username="mauro" passwd="aa&1111111" template_name="4 prodotti" filename="/home2/svaghine/public_html/pileperorologi/cron/articoli.csv"

I'm using absolute paths
username = username Administrator
psw = psw Administrator (password is in this format for ab & 111111 where there is a - & -)
csv files in there are about 3000 lines

Once I started the cron returns the mail with the following message:
JCron Daemon

A cron task was failed, prodotto csv crashed when we tried to run it.

Thank you in advance for the help


Hey Mauro,

Your cron string looks all OK to me. Now I don't support JCron, so you will have to ask them what the message means. What if you run the cron string from the control panel of your hosting provider?

Using JCron is not really useful for CSVI because you are still limited to the server limits where as using the control panel cron, you usually don't have the server limits.

Drupal Cron Troubleshooting

July 4, 2009 ∑ 6 comments

If you're having problems with Drupal cron - like cron runs are timing out or running out of memory - here's a quick hack to figure out which module is causing the problems.

Edit the includes/ file, and find the function module_invoke_all. Insert the line indicated below to have a notice added to the logs (admin/logs/watchdog) for each module cron is running. You can then figure out the last module running when the problems occur.

foreach (module_implements($hook) as $module) {
  $function = $module .'_'. $hook;
  if ($hook == 'cron') watchdog('cron', "hit $module cron");   // add this line

Thanks to Peter Lindstrom for the tip.



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