open(FILE, filename);
@LINES = <FILE>;
close(FILE);

##</code><code>##

$LINES[n] = 'some new text';

##</code><code>##

open(FILE, filename1);
@LINES = <FILE>;
close(FILE);
open(FILE2, filename2);
@LINES2 = <FILE2>;
close(FILE2);

for $i (n .. p) {
    $LINES[$i] = $LINES2[$i];
}

##</code><code>##

open(FILE, filename);
for $i (0 .. $#LINES) {
	print FILE "$LINES[$i]";
}
close(FILE);