use strict;

my $counter=1;
$/="</Rec $counter>";
my $first_file;
my $second_file;

while (my $record=<DATA>) {
	$first_file .= $record unless $record=~m/var2 = 3/;
	$second_file .= $record if $record=~m/var2 = 3/;
	$counter++;
	$/="</Rec $counter>";
}
print "FIRST FILE: $first_file\nSECOND FILE: $second_file\n";

##</code><code>##

__DATA__
<Rec 1>
var2 = 5
some text
some text
some text
some text
</Rec 1>
<rec 2>
var2 = 3
some text
some text
some text
some text
some text
some text
some text
some text
</Rec 2>
<Rec 3>
var2 = 7
some text
some text
some text
some text
some text
some text
</Rec 3>
<rec 4>
var2 = 3
some text
some text
some text
some text
some text
some text
some text
some text
</Rec 4>