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cron - pass crontab a variable and read it from PHP?

Hey everyone,

I hope you're all doing well. I have a question regarding using crontab and passing a variable to it, which I then need to read from PHP.

So, here's the situation. I have a cron job set up using crontab, which runs a PHP script at a specific time. This PHP script needs to be able to read a variable that I pass to it through the crontab command.

I've already tried looking for a solution online, but I couldn't find any clear answers. It seems like a straightforward problem, but I just can't figure out the best way to do it.

Does anyone have any experience with this? How can I pass a variable to crontab and then access it from within my PHP script?

Any help would be greatly appreciated. Thanks in advance!

All Replies


Hey there,

I've faced a similar situation before and managed to solve it by using environment variables. Here's how you can do it:

First, within your crontab command, you can pass the variable as an environment variable. For example:

* * * * * MY_VARIABLE=example php /path/to/your/script.php

In your PHP script, you can access this variable using the $_ENV superglobal. For instance:
$myVariable = $_ENV['MY_VARIABLE'];
echo $myVariable;

By doing this, you'll be able to pass a variable from crontab and access it within your PHP script. It provides a straightforward and reliable way to handle such situations.

Hope that helps! Let me know if you have any further questions.



I've encountered a similar situation where I needed to pass a variable to crontab and access it in my PHP script. The approach I found effective involves using a temporary file to transmit the variable.

To begin, in your crontab command, you can pass the variable as a parameter and save it to a temporary file. For example:

* * * * * echo 'example' > /tmp/my_variable.txt && php /path/to/your/script.php

Inside your PHP script, you can read the contents of the temporary file to access the variable. Here's an example:
$myVariable = trim(file_get_contents('/tmp/my_variable.txt'));
echo $myVariable;

By leveraging this method, the variable is written to the file before executing the PHP script, allowing you to read its contents within your script. Just ensure that the temporary file is properly managed, such as deleting it after use or using unique file names to avoid conflicts.

Give it a try and let me know if you encounter any issues. I'm here to assist you further.



I had a similar requirement of passing variables to a PHP script via crontab, and I found a different approach that worked for me. Instead of using environment variables, I utilized command line arguments.

In your crontab command, you can pass the variable as a command line argument to the PHP script. For instance:

* * * * * php /path/to/your/script.php arg1=value arg2=example

Inside your script.php file, you can access these command line arguments using the $argv array. Each argument will be available as a separate element in the array. Here's an example:
$arguments = getopt("", ["arg1:", "arg2:"]);
$arg1 = isset($arguments['arg1']) ? $arguments['arg1'] : "";
$arg2 = isset($arguments['arg2']) ? $arguments['arg2'] : "";

echo $arg1 . " " . $arg2;

By following this approach, you can easily pass and retrieve variables within your PHP script. It worked well for me, and I hope it helps you too!

Feel free to ask if you have any doubts or need further assistance.

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