require '/path/to/some/script.pl';

##</code><code>##

use lib '/path/to/some';
require 'script.pl';

##</code><code>##

package module;

use warnings;
use strict;

require 'required1.pl';
subroutine();

warn 'module INC: ', $INC{'required1.pl'};

__PACKAGE__

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;

warn "Loading 1";

sub subroutine {
    my $file = (caller)[1];
    $file =~ s=.*/==;
    warn 'subroutine defined in ', $file;
}

subroutine();

1;

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;

use FindBin;
use lib $FindBin::Bin;

require 'required1.pl';
use module;
warn 'script INC ', $INC{'required1.pl'};

subroutine();

##</code><code>##

my %_INC = %INC;

# ...

%INC = %_INC;