#!/usr/bin/ perl -pi.bak
use strict; use warnings;

use vars qw($search $replace);

BEGIN {
    $search="position 20 0 100\norientation 0.0 -0.8 0 -0.2\nfieldOfView 0.75";
    $replace="position 0 -14 120\norientation 0 -0.3 10 0\nfieldOfView 0.23";

    $/=undef;
	$_ = 0;
}

s/$search/$replace/msg;