Perl - count variables in source code

varcount.pl

use Data::Dumper;
# usage: perl varcount.pl source.pl
open(X,$ARGV[0]);
my @lines = <X>;
close(X);

my $lineCount = 1;
my $variables = {};

foreach my $line (@lines){
	while($line =~ /\$(\w+)/g){
		my $scalar = $1;
		if($scalar ne '_'){
			$variables->{$scalar}->{count}++; 
			push(@{$variables->{$scalar}->{lines}},$lineCount); 
		}
	}
	$lineCount++;
}

print Dumper $variables;