How can I automatically put same header, footer and layout to every pages generated by this PHP code?

Question

Here is my code

<?php
$myFile = "hidata.txt";
$fh = fopen($myFile, 'r');
$counter = 1;
$page = 2;

while(false !== ($theData = fgets($fh))) {
    if ( $counter > 10){
         file_put_contents( '/i', $page.".php", '<li>' . $theData . '</li>' . PHP_EOL, FILE_APPEND  );
       if ($counter == 20){
               $counter=10;
               $page++;
       }
    }else{
    echo ('<li>' . $theData . '</li>');
   }
   $counter++;
}
fclose($fh);
?>

This code automatically generates new .php pages everytime the hidata.txt reaches more than 10,20,30... lines of texts. I want every generated pages to automatically have same header, footer and layout. How can I do that in this code?

Edit: I tried it but not working

<?php
    $myFile = "hidata.txt";
$fh = fopen($myFile, 'r');
$counter = 1;
$page = 2;
$newpage = true;


while(false !== ($theData = fgets($fh))) {
    if ( $counter > 10){
        if ($newpage) {
            file_put_contents(..... $header .....);
            $newpage = false;
        }
        file_put_contents( '/i', $page.".php", '<li>' . $theData . '</li>' . PHP_EOL, FILE_APPEND  );
        if ($counter == 20){
            $counter=10;
            $page++;
            $newpage = true;

        }
    }else{
        echo ('<li>' . $theData . '</li>');
    }
    $counter++;
}
fclose($fh);
?>

Edit 2: Here is my hidata.txt

data1
data2
data3
data4
data5

and so on

And here is my header.php

<h1>Test</h1>

Answer 1

[edit - sample code]

$page = 2;
$newpage = true;


while(false !== ($theData = fgets($fh))) {
    if ( $counter > 10){
         if ($newpage) {
            file_put_contents(..... $header .....);
            $newpage = false;
            }
         file_put_contents( '/i', $page.".php", '<li>' . $theData . '</li>' . PHP_EOL, FILE_APPEND  );
       if ($counter == 20){
               $counter=10;
               $page++;   
               $newpage = true;

       }

---

[original]

You could add code something like this:

if ( $counter > 10){  

 /********** YOUR CODE HERE *****/
  if (first putfor this page) {
      file_put_contents('/i',$page.".php",$header . PHP_EOL, FILE_APPEND);
    }
/*******                  *****/  

     file_put_contents( '/i', $page.".php", '<li>' . $theData . '</li>' . PHP_EOL, FILE_APPEND  );

Similary, append the "footer" when you $page++; . You'll have to check before the fclose that the final footer was written.

$header could be a string like require_once("header.php") , or the result of a file_get_contents , depending on what you need. Ditto the footer.