How to create cron job using PHP?
I'm new to using cron job. I don't even know how to write it. I have tried to search from internet, but I still don't understand it well. I want to create a cron job that will execute my code every minute. I'm using PHP to create it. It is not working.
Example
run.php (Code that will be executed every minute)
<?php
echo "This code will run every minute";
?>
cron.php
<?php
$path = dirname(__FILE__);
$cron = $path . "/run.php";
echo exec("***** php -q ".$cron." &> /dev/null");
?>
Suppose that these two files are in the same folder.
Is the code that I did wrong? If wrong, please kindly tell me how to fix it.
Solution 1:
This is the best explanation with code in PHP I have found so far:
http://code.tutsplus.com/tutorials/managing-cron-jobs-with-php--net-19428
In short:
Although the syntax of scheduling a new job may seem daunting at first glance, it's actually relatively simple to understand once you break it down. A cron job will always have five columns each of which represent a chronological 'operator' followed by the full path and command to execute:
* * * * * home/path/to/command/the_command.sh
Each of the chronological columns has a specific relevance to the schedule of the task. They are as follows:
Minutes represents the minutes of a given hour, 0-59 respectively.
Hours represents the hours of a given day, 0-23 respectively.
Days represents the days of a given month, 1-31 respectively.
Months represents the months of a given year, 1-12 respectively.
Day of the Week represents the day of the week, Sunday through Saturday, numerically, as 0-6 respectively.
So, for example, if one wanted to schedule a task for 12am on the first day of every month it would look something like this:
0 0 1 * * home/path/to/command/the_command.sh
If we wanted to schedule a task to run every Saturday at 8:30am we'd write it as follows:
30 8 * * 6 home/path/to/command/the_command.sh
There are also a number of operators which can be used to customize the schedule even further:
Commas is used to create a comma separated list of values for any of the cron columns.
Dashes is used to specify a range of values.
Asterisksis used to specify 'all' or 'every' value
Visit the link for the full article, it explains:
- What is the format of the cronjob if you want to enter/edit it manually.
- How to use PHP with SSH2 library to authenticate as the user, which crontab you are going to edit.
- Full PHP class with all necessary methods for authentication, editing and deleting crontab entries.
Solution 2:
In the same way you are trying to run cron.php, you can run another PHP script. You will have to do so via the CLI interface though.
#!/usr/bin/env php
<?php
# This file would be say, '/usr/local/bin/run.php'
// code
echo "this was run from CRON";
Then, add an entry to the crontab:
* * * * * /usr/bin/php -f /usr/local/bin/run.php &> /dev/null
If the run.php script had executable permissions, it could be listed directly in the crontab, without the /usr/bin/php part as well. The 'env php' part, in the script, would find the appropriate program to actually run the PHP code. So, for the 'executable' version - add executable permission to the file:
chmod +x /usr/local/bin/run.php
and then, add the following entry into crontab:
* * * * * /usr/local/bin/run.php &> /dev/null
Solution 3:
Added to Alister, you can edit the crontab usually (not always the case) by entering crontab -e in a ssh session on the server.
The stars represent (* means every of this unit):
[Minute] [Hour] [Day] [Month] [Day of week (0 =sunday to 6 =saturday)] [Command]
You could read some more about this here.