subs - Perl pragma to predeclare sub names
use subs qw(frob); frob 3..10;
This will predeclare all the subroutine whose names are in the list, allowing you to use them without parentheses even before they're declared.
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
See "Pragmatic Modules" in perlmodlib and "strict subs" in strict.
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.