Php executing a bash script with at command - php

Question

Hello I'am trying to execute a shell command in my php script but it is not working.
My php script :
//I save the Order
$holdedOrder->save();
$id = $holdedOrder->id;
$old_path = getcwd();
chdir(__DIR__.'/../');
$scriptFile = 'anacron_job_unhold_order.sh';
$bool = file_exists($scriptFile);
//$bool is true !
//this command works in shell but not in here do not know why
$s = shell_exec("echo \"/usr/bin/bash $scriptFile $id\" | /usr/bin/at now +$when");
chdir($old_path);
return [$s,$bool];
$when has a valid value 4 hours or 4 days ...
The command will be :
echo bash anacron_job_unhold_order.sh 29 | at now +1 minutes
the output is null. Trying it with exec() is returning 127 code
Edit :
I removed www-data from /etc/at.deny and still the same problem

Answer 1

The command shell_exec("echo \"/usr/bin/bash $scriptFile $id\" | /usr/bin/at now +$when"); is probably causing the issue, you should take a closer look on how at works.
The command should be something like
at [options] [job...]
To give a job to at from the command instead of STDIN, use heredoc syntax
at now + 1 minute <<< 'touch /tmp/test'
So the PHP code should be something like;
$s = shell_exec("/usr/bin/at now + {$when} <<< '/usr/bin/bash {$scriptFile} {$id}'");
exec($s, $output, $return_var);