Description

What is this qw() or qw// ? (#5)

Convenience

The qw() function is one of the many ways in which Perl helps to
 make it easier to write code. Wherever you need to construct a list
 like this:

    my @names = ('Kernighan', 'Ritchie', 'Pike');

you can use qw to do the same thing more simply:

    my @names = qw(Kernighan Ritchie Pike);

Delimeters

You can use any non-alphanumeric, non-whitespace delimeter to
 surround the qw() string argument. You'll often see qw//, for
 example.

from: http://www.perlmeme.org/howtos/perlfunc/qw_function.html

Changes