my $global;

{
    my $local_outer;

    # $global known here
    # $local_outer known here
    # $local_inner unknown here

    {
        my $local_inner;

        # $global known here
        # $local_outer known here
        # $local_inner known here
    }

    # $global known here
    # $local_outer known here
    # $local_inner unknown here

    # An entirely different $local_inner:
    my $local_inner;
}

# $global known here
# $local_outer unknown here
# $local_inner unknown here

# An entirely different $local_outer:
my $local_outer;

# An entirely different $local_inner:
my $local_inner;

##</code><code>##

{
    open my $fh, '<', $filename;

    # ... read and process file contents here ...

    # As soon as the closing brace is reached:
    # 1) $fh goes out of scope - available for garbage collection
    # 2) an automatic "close $fh" is performed
}