This is the program I came up with from your description (I hope it's what you meant). Problems are often better described with code, rather than English.

use strict;
use warnings;

my $variable = 1;
print $variable;

subroutine();

sub subroutine {
    my $variable = 2;
    print $variable;
}
#Output:
#12
[download]

Each print prints the value of the $variable it's closest to (in this example only, it's not a rule).

I fairly sure you will benefit from reading Coping with Scoping. It'll help you understand Perl's notion of global and local variables.