#!/bin/perl -w
use strict;
undef $/;                     # so <DATA> will slurp the entire file
my $string=<DATA>;
$string=~ s{/\*.*?\*/}{}gsx;  # do not forget the s modifier so . matches \n too
print $string;

__DATA__
A text /* with comments */, some
even /* cross several
lines */, some
even
/* cross many,
many,
many
*/
lines