How to modify cron job with php?

Question

PHP

There is a job in cron. You need to somehow change the frequency of this task using php. How to do it?

Answer 1

Run the php file every minute, and inside this script, already determine whether it is time for it to run. Get the most correct and safe option.

Answer 2

Edit /etc/crontab.
From a security point of view, it's a huge hole to give PHP access to this file.

Answer 3

//получаем список работ для пользователя user
$currentJobs = shell_exec("crontab -u user -l");
//вносим нужные изменения в расписание работ
...
//сохраняем все во временном файле
$filename = tempnam(sys_get_temp_dir(), 'crontab');
file_put_contents($filename, $currentJobs);
//обновляем cron
exec("crontab -u user " . $filename);

Just keep in mind that the user from which this PHP script is run must have rights to edit the cron user user.