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