>perl -le "use strict; use Env; print $CONFIG;"
Global symbol "$CONFIG" requires explicit package name

##</code><code>##

>perl -le "use strict; use Env qw( $WINDIR ); print $WINDIR;"
E:\WINNT

##</code><code>##

>perl -le "use strict; use Env; our $WINDIR; print $WINDIR;"
E:\WINNT

##</code><code>##

>perl -le "use strict; print $ENV{WINDIR};"
E:\WINNT