use strict;
use CGI::Simple qw(-debug2);

my $q = CGI::Simple->new();

for my $key ( $q->param() ) {

   # this:
   for my $value ( $q->param($key) ) {
      printf "'%s' has value '%s'\n", $key, $value;
   }

   # or this:
   print "'$key' has value(s):\n",
      map { "- $_\n" } $q->param($key);
}
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