#!perl
use Data::Dumper qw/Dumper/;

open my $fh,"<",'/tmp/tst';
my $outer=$fh;

print 0+($outer == $fh),": ", Dumper $fh;
{
    open my $fh,"<",'/tmp/tst';
    print 0+($outer == $fh),": ", Dumper $fh;
}