如何使用PHP创建文件？ （Ubuntu的）

This may be marked as duplicate, but everything else I tried here didn't work. I am trying to create a file in PHP using this:

<?php

$con = $sup;
$fp = fopen($_SERVER['DOCUMENT_ROOT'] . "/var/www/HDdeltin/" . $sup , "wb");
fwrite($fp,$con);
fclose($fp);

?>

I am using ubuntu(xfce) What is wrong with this?

$fp = fopen($_SERVER['DOCUMENT_ROOT'] . "/var/www/HDdeltin/" . $sup , "wb");

is incorrect: normally $_SERVER['DOCUMENT_ROOT'] is already /var/www/. Try

$fp = fopen($_SERVER['DOCUMENT_ROOT'] . "/HDdeltin/" . $sup , "wb");

or

$fp = fopen("/var/www/HDdeltin/" . $sup , "wb");

depending on whether you want your file under the document root or under a specific location.

This is what I came up with:

<?php
$text = "This will be placed in your file.";
$con = "test.txt";
$fp = fopen($_SERVER['DOCUMENT_ROOT']. "/HDdeltin/$con", "wb");
fwrite($fp,$text);
fclose($fp);
?>

This seems to works if the folder HDdeltin exists, otherwise it will return an error.

$text would be the replacement of your $sub because you didn't declare one. And I removed the /var/www/ part since this is exactly what $_SERVER['DOCUMENT_ROOT']; should return.

<?php

$con = $sup;
$fp = fopen($_SERVER['DOCUMENT_ROOT'] . "/var/www/HDdeltin/" . $sup , "wb");
fwrite($fp,$con);
fclose($fp);

?>

I don't know if you can use the last parameter 'wb' for the fopen function. Try to use only 'w' option then let us know if it works.