You would be better to always use strictures (use strict; use warnings;) and fix each error or warning by understanding why it is being generated and fixing the root cause rather than applying band aids to patch over the issue. Maybe you could tell us what the real issue is?

so...

my $foo = 3;
my $bar = "keyword mania";
my @blivitz = "(some set of value);
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within code blocks, subs, or suchlike, when you need them ...and only when you need them.

For example:

my $bar = "keyword mania";
... (do something);
... (and something more);
bax($bar);                    # send $bar to sub bax for further proce
+ssing
...(more code)

{                             # bare block
my @blivitz = ("7", '144', '1.16', "bat",);  # @blivitz values availab
+le only in this block
... do something with the elements of @blivitz;
}                             # end block

sub bax {                     # and here's the sub, bax
    my $foo = "3";
    ...do something to the value in $bar (a global) with $foo (availab
+le only in the sub);
    return (something);
}
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Make sure you understand scoping and the issues created by making your variables global.

For lexical variables, you may be able to do something with Lexical::Persistence.

#!perl

use warnings;
use strict;

use Lexical::Persistence;

# Create a new dynamic closure.
my $dc = Lexical::Persistence->new();

# Prime a variable with a value.
$dc->set_context( _ => { '$cat' => "persistent" } );

# Call a function within it.
$dc->call(\&function);
exit;

sub function {
  # $cat is already initialized.
  print "persistent cat is '", my($cat), "'\n";
}
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