As user DrChalta pointed out in a forum post, there is an alternative to wget, as long as your PHP installation has the cURL extension installed and enabled. For sterters, you need to save the following PHP script as backup.php somewhere your host's cron feature can find it. Please note that this is a command-line script and needn't be located in your site's root; it should be preferrably located above your site's root, in a non-web-accessible directory.

The script below is a modification over DrChalta's original script, taking into account changes made in later versions of our software. In order to configure it for your server, you only have to change the first three lines.

<?php
define('SITEURL', 'http://www.example.com'); // Base URL of your site
define('SECRETKEY', 'MySecretKey'); // Your secret key
define('PROFILE',1); // The profile's ID

// ====================== DO NOT MODIFY BELOW THIS LINE ======================
$curl_handle=curl_init();
curl_setopt($curl_handle,CURLOPT_URL,
SITEURL.'/index2.php?option=com_akeeba&view=backup&key='.
SECRETKEY.'&format=raw&profile='.PROFILE.'&format=raw');
curl_setopt($curl_handle,CURLOPT_FOLLOWLOCATION,TRUE);
curl_setopt($curl_handle,CURLOPT_MAXREDIRS,10000); # Fix by Nicholas
curl_setopt($curl_handle,CURLOPT_RETURNTRANSFER,1);
$buffer = curl_exec($curl_handle);
curl_close($curl_handle);
if (empty($buffer))
    echo "Sorry, the backup didn't work.";
else
    echo $buffer;
?>

Where www.yoursite.com and YourSecretKey should be set up as discussed in the previous section.

In order to call this script with a schedule, you need to put something like this to your crontab (or use your host's CRON feature to set it up):

0 3 * * 6 /usr/local/bin/php /home/USER/backups/backup.php

Where /usr/local/bin/php is the absolute path to your PHP command-line executable and /home/USER/backups/backup.php is the absolute path to the script above.

If you set up your cron schedule with a visual tool (for example, a web interface), the command to execute part is "/usr/local/bin/php /home/USER/backups/backup.php".

Thank you DrChalta for this wonderful tip!

As one of our users pointed out in the support forum, finding the correct command to issue for the CRON job is tricky. What he writes applies not only to his host, SiteGround, but many other commercial hosts as well. We'll simply quote our user, bzcoder.

In the CPanel for SiteGround there is a cronjob option, you create a cronjob using that and use:

curl -b /tmp/cookies.txt -c /tmp/cookies.txt -L --max-redirs 1000 -v "<url>"

as your command.

Replace <url> with your backup URL. Make sure to use the initial url displayed on the backend NOT the final URL when you run the backup manually (been there, done that) - when you do that you end up with a url that doesn't work because of the extra parameter used in continuing the backup process.