Disclaimer: I never tried this feature that is declared "experimental", so I really don't know if it works at all.

From Getopt::Long POD:

Warning: What follows is an experimental feature.

Options can take multiple values at once, for example

--coordinates 52.2 16.4 --rgbcolor 255 255 149

This can be accomplished by adding a repeat specifier to the option specification. Repeat specifiers are very similar to the {...} repeat specifiers that can be used with regular expression patterns. For example, the above command line would be handled as follows:

GetOptions('coordinates=f{2}' => \@coor, 'rgbcolor=i{3}' => \@color);

The destination for the option must be an array or array reference.

It is also possible to specify the minimal and maximal number of arguments an option takes. foo=s{2,4} indicates an option that takes at least two and at most 4 arguments. foo=s{,} indicates one or more values; foo:s{,} indicates zero or more option values.

So, if I understand correctly, an option like:

'files|f:s{,}' => \@input_array->{files}

could work as you expected.