perlmod             Perl modules: how they work 
        perlmodlib          Perl modules: how to write and use 
        perlmodstyle        Perl modules: how to write modules with style 
        perlmodinstall      Perl modules: how to install from CPAN 
        perlnewmod          Perl modules: preparing a new module for distribution

{ 
    package MyPack::Funcs; 
    .... some code ... 
    our $myvar = 'package var'; 
    1; # optional for inclusive packages, required for external 
} 
 
{ 
   package MyPack; 
   import MyPack::Funcs;   
 
   print $MyPack::Funcs::myvar; 
 
   ... code ... 
    1; # optional for inclusive packages 
} 
 
package main; 
 
import MyPack; 
 
... code ...

  use Exporter(); 
  our @ISA = 'Exporter'; 
  # explicit exports requires  qw(sub1 sub2) in calling package 
  our @EXPORT = "sub1 sub2 sub3";  
  # global exports 
  our @EXPORT_OK = "sub4 sub5 $var";

#!/usr/bin/perl 
 
use strict; 
use warnings; 
 
# any vars declared as globals will be seen by packages 
 
my $name = "ABCD";  # defined as global $main::name  
 
{ 
    use strict;                      # keep consistent for extern modules 
    use warnings; 
    package New; 
    # do not do this - you are depending on a extern variable 
    # that will lead to issues if module is extracted to external file and 
    # used by another script that does not declare the var before using the 
    # package. 
    # $name = "XYZ";         # updating global $main::name  
 
    # use a package var and then share with others if they need it 
    our $name = "XYZ";     # update package $name 
    print "Inside ". __PACKAGE__ ." name = $name \n"; 
} 
 
package main; 
    printf "\$%s::name = %s\n", __PACKAGE__, $name; 
    print "\$New::name  = $New::name\n";

use strict; 
use vars qw ($name); 
$name = "ABCD";   
 
package New;  
use vars qw ($name); 
$name = "XYZ";  
print "$name \n";   
 
package main;  
print "$name \n";

my $name = "ABC";  # program or global scope 
{ 
   my $name = "ABC";  # file scope (static) cannot be changed once set 
   sub static_name { $name }   
} 
 
sub { 
     my $name = "XYZ"; # function scope 
     for (@x) { 
          my $name = "123";  # block scope 
     } 
}

{ 
   my $name = "ABC"; 
   sub static_name { $name } 
    
   print static_name(), "\n"; 
    
   $name = 'XYZ'; 
   print static_name(), "\n"; 
    
   $name = 'Bob'; 
} 
 
print static_name(), "\n";

sub static_name {  
    my $name = "ABC"; 
    return $name; 
}

sub static_name { "ABC" }

{ 
   my $name = "ABC"; 
   sub static_name { $name } 
   print static_name(), "\n"; 
   $name = 'XYZ'; 
   print static_name(), "\n"; 
   $name = 'Bob'; 
} 
 
$name = "Ann"; 
print static_name(), " = $name \n";

#!/usr/bin/perl 
 
use strict; 
use warnings; 
use Readonly; 
 
Readonly::Scalar  my $name => 'Bob'; 
 
print "$name\n"; 
 
$name = 'Ann';