vars - Perl pragma to predeclare global variable names (obsolete)
use vars qw($frob @mung %seen);
NOTE: For variables in the current package, the functionality provided by this pragma has been superseded by our declarations, available in Perl v5.6.0 or later. See "our" in perlfunc.
our
This will predeclare all the variables whose names are in the list, allowing you to use them under "use strict", and disabling any typo warnings.
Unlike pragmas that affect the $^H hints variable, the use vars and use subs declarations are not BLOCK-scoped. They are thus effective for the entire file in which they appear. You may not rescind such declarations with no vars or no subs.
$^H
use vars
use subs
no vars
no subs
Packages such as the AutoLoader and SelfLoader that delay loading of subroutines within packages can create problems with package lexicals defined using my(). While the vars pragma cannot duplicate the effect of package lexicals (total transparency outside of the package), it can act as an acceptable substitute by pre-declaring global symbols, ensuring their availability to the later-loaded routines.
my()
See "Pragmatic Modules" in perlmodlib.
To install Env, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Env
CPAN shell
perl -MCPAN -e shell install Env
For more information on module installation, please visit the detailed CPAN module installation guide.