use strict;
use warnings;
use 5.012;

our $x;

use Data::Dumper;
say Dumper($main::{x});     #%main:: is the name of the symbol table
say Dumper($main::{say});
say Dumper($main::{print});


--output:--
$VAR1 = *::x;   #typeglob for 'x', in package ::(shorthand for main::)

$VAR1 = undef;

$VAR1 = undef;


##</code><code>##

use strict;
use warnings;
use 5.012;

use subs qw( print );

sub print {
    printf "%s %s\n", shift, 'world';
}

print 'hello';

--output:--
hello


##</code><code>##

use strict;
use warnings;
use 5.012;

use Data::Dumper;
say Dumper($main::{chdir});

--output:--
$VAR1 = undef;


##</code><code>##

use strict;
use warnings;
use 5.012;

use subs qw( chdir );

sub chdir {
    printf "%s %s\n", shift, 'world';
}

chdir 'hello';

--output:--
hello world