##
$data =~ m/Line3 : ([^\n]*)/s;
##
##
use warnings;
use strict;
my $data = join( '', );
print "[$data]\n\n";
$data =~ m/Line3 : (.*?)\n/s or die;
print "match: [$1]\n";
$data =~ m/Line3 : ([^\n]*)/s or die;
print "match: [$1]\n";
__DATA__
Line1 : Dit is de eerste regel
Line2 : Dit is de tweede regel
Line3 : Dit is de derde regel
Line4 : Dit is de vierde regel