PHP unlink OR rewrite own/current file by itself

Question

Task: Cut or erase a file after first walk-through.

i have an install file called "index.php" which creates another php file.

<? 
/* here some code*/
$fh = fopen($myFile, 'w') or die("can't open file");
$stringData = "<?php \n
echo 'hallo, *very very long text*'; \n 
?>";
fwrite($fh, $stringData);
/*herecut"/
/*here some code */

after the creation of the new file this file is called and i intent to erase the filecreation call since it is very long and only needed on first install.

i therefor add to the above code

echo 'hallo, *very very long text*'; \n 
***$new= file_get_contents('index.php'); \n
$findme   = 'habanot';
$pos = strpos($new, $findme);
if ($pos === false) {
$marker='herecut';\n
$new=strstr($new,$marker);\n
$new='<?php \n /*habanot*/\n'.$new;\n
$fh = fopen('index.php', 'w') or die 'cant open file');
$stringData = $new;
fwrite($fh, $stringData);
fclose($fh);***    

?>";
fwrite($fh, $stringData);]}

Isnt there an easier way or a function to modify the current file or even "self destroy" a file after first call?

Regards

EDIT: found the way to edit, sorry to zaf

unlink(__FILE__);

can be used to delete the "helper file" after execution.

Answer 1

unlink(__FILE__);

for the "helper" file seems necessary since i cant find a way to modify the php-file inuse/process.