not need other procedures
use simple
Kod:
$file=file('/etc/passwd');
$i=-1;
while($file[++$i]):
$u=explode(':', $file[$i]);
$users = fopen("user.txt","ab");
$wrtusers = fwrite($users,$u['0']."\n");
echo '<font color="green">'.$u['0'].'</font>'."<br>";
endwhile;