Running PHP with CRON on Ubuntu

Question

Please tell me what am I doing wrong, why doesn't this run:

 3 * * * * /usr/bin/php -q /var/www/CRON/hourly.php > /var/www/logPHP.log

logPHP.log is made, but is empty when this is run. If I replace the 3 with an *, the script starts running but never ends.

When I copy this in Terminal:

/usr/bin/php -q /var/www/CRON/hourly.php > /var/www/logPHP.log

Everything runs smoothly as it is supposed to.

Ubuntu 10.04 LTS, PHP 5.3.2-1ubuntu4.9 with Suhosin-Patch (cli)

Answer 1

If you use crontab -e to create cron entries ignore the missing user part.

Check the syntax for cron entries, you are missing the "user", e.g. :

3 * * * * some_user_here /usr/bin/php -q /var/www/CRON/hourly.php > /var/www/logPHP.log

Check that some_user_here as writing permissions to the log file by verifying that there are no errors when you do this:

su -m some_user_here
cd /var/www/
touch logPHP.log

Check that php executable is present where you specified by confirming that /usr/bin/php is return when you do this:

whereis php

Did you use a guide when setting up your cron entry, e.g. https://help.ubuntu.com/community/CronHowto ?

Answer 2

You are logging standard output (STDOUT) to a logfile, but you are ignoring standard error (STDERR). It is almost always a good idea to send STDERR to a logfile. If you ignore the errors, you may be missing out on critical problems.

Modify your cronjob to redirect STDERR to the same logfile, using 2>&1:

3 * * * * some_user_here /usr/bin/php -q /var/www/CRON/hourly.php > /var/www/logPHP.log 2>&1

Or alternatively, send the errors to a second logfile:

3 * * * * some_user_here /usr/bin/php -q /var/www/CRON/hourly.php > /var/www/logPHP.log 2> /var/www/logPHP.err

Then, allow the script to run again, and check /var/www/logPHP.log for errors. At that point, you will probably be able to solve the problem on your own. If you still need help, you can update your answer here with the output of the error log.