read and write 5 lines

[Anon]

ok...text file with 5 lines of text.
trying to read top 4 lines...
then....
write new text (to same file) followed by the 4 lines
and end up with 5 lines again....

so far....strange things happen!!

$f = file($file3);
$a=$f[1];
$b=$f[2];
$c=$f[3];
$d=$f[4];

$fp = fopen("$file3", "w");
fwrite($fp, "NEW LINE OF TEXT\n$a\n$b\n$c\n$d\n");
fclose($fp);

help......

[lentin64]

READ:
$file = file("thising.htm");
for($i=1; $i < 5; $i++) {
echo $file[$i];
}

I don't know how to write 5 lines..