Open file in PHP

[rhaddad]

Hi guys, i'm new in PHP, i'm trying to create a "txt" file using PHP where i'll store the username and password for a user. I wrote the following:

$tmpfile = "testFile.txt";
$tmpfile = fopen($tmpfile, 'w') or die("can't open file");

$muser = $myusername;
fwrite($tmpfile,$muser);

$mpassword = $mypassword;
fwrite($tmpfile,$mpassword);
   
fclose($tmpfile);

what I don;t know to do is how to set the username and password each one on a separated line?  Heeeeeeeeeeeeeeeeeeelp 

[nimesha]

$tmpfile = "testFile.txt";
$tmpfile = fopen($tmpfile, 'w') or die("can't open file");

$muser = $myusername;
fwrite($tmpfile,$muser);
fputs($tmpfile, "\n");
$mpassword = $mypassword;
fwrite($tmpfile,$mpassword);
  
fclose($tmpfile);

Note: set testFile.txt read write permission