vars - Perl pragma to predeclare global variable names
use vars qw($frob @mung %seen);
NOTE: For use with variables in the current package for a single scope, the functionality provided by this pragma has been superseded by our declarations, available in Perl v5.6.0 or later, and use of this pragma is discouraged. See "our" in perlfunc.
This pragma will predeclare all the variables whose names are in the list, allowing you to use them under use strict, and disabling any typo warnings for them.
Unlike pragmas that affect the $^H hints variable, the use vars and use subs declarations are not lexically scoped to the block they appear in: they affect the entire package in which they appear. It is not possible to rescind these declarations with no vars or 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.
See "Pragmatic Modules" in perlmodlib.
To install less, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell
For more information on module installation, please visit the detailed CPAN module installation guide.