my $test = '`dir $path /-c`';

my $free = &bleah( 'u:' );
print $free, "\n";

my $free = &bleah( 'c:' );
print $free, "\n";

sub bleah
{
   my $path = shift;
   # 
   #  1. evaluate the perl code in $test
   #     when eval'ed, $path gets set internally
   #  2. get the last line of the result list
   #  3. match it against the given pattern
   #  4. the captured item gets returned in its own list
   #  5. return the captured item only (a scalar)
   #  6. voila - bytes free from DOS.
   #
   return ((eval $test)[-1] =~ m/(\d+) bytes free/)[0]; # yow!
}