In the interest of tmtowtdi, here's an alternate Getopt::Declare scenario that sets up the $all and @words variables in action blocks. Here I decided to make the search words required (but without option description), and just allow for -a as an abbrev. of -all (instead of using the --all version):

  #!/usr/bin/perl -w
  use strict;
  use LWP::UserAgent;
  use Getopt::Declare;
  use vars qw/$all @words/;

  my $opts = Getopt::Declare->new(<<'EOS');

      -a[ll]           List all matches
                        {$all = 1}
      <terms:s>...     [required]
                        {@words = @terms}
  EOS

  for my $word (@words) {
      # insert fetch code ...
      # ...
      last unless $all;
  }
  __END__
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