Question

How can I run a cron task in Linux?

Following this Q&A,I have this cron task to run - just writing some info to a txt file,

// /var/www/cron.php
$myfile = fopen("cron.txt", "w") or die("Unable to open file!");
$txt = "John Doe\n";
fwrite($myfile, $txt);
$txt = "Jane Doe\n";
fwrite($myfile, $txt);
fclose($myfile);

But after adding the cron task via my terminal,

crontab -e

and then,

* * * * * /usr/bin/php /var/www/cron.php &> /dev/null

But when I open cron.txt, there is nothing in it.

Why? What have I missed?

Answer 1

按完整路径[{1}}

更改cron.txt

/var/www/my_system/cron.txt

或移至目录：

// /var/www/cron.php
$myfile = fopen("/var/www/my_system/cron.txt", "w") or die("Unable to open file!");
$txt = "John Doe\n";
fwrite($myfile, $txt);
$txt = "Jane Doe\n";
fwrite($myfile, $txt);
fclose($myfile);

再试一次。

Answer 2

I would eliminate the redirect to /dev/null until you're sure you're not getting an error message.

My guess is "permissions".

SUGGESTIONS:

Execute /usr/bin/php /var/www/cron.php manually, from the command prompt, to make sure the PHP script is OK.
Identify the directory "myfile.txt" is being written to.
Make sure both the directory and myfile.txt are writable.

Here are a couple of links with other troubleshooting hints:

Linux cron task - how to add and run a cron task?

2 个答案: