use strict;
use warnings;
use Getopt::Long;

my %opts;

GetOptions(
  'address=s' => sub { $opts{$_[0]} = $_[1]; }
  'user=s' => sub { $opts{$_[0]} = $_[1]; }
  'pass=s' => sub { $opts{$_[0]} = $_[1]; }
  'protocol=s' => sub { $opts{$_[0]} = $_[1]; }
  'snmp_community=s' => sub { $opts{$_[0]} = $_[1]; }
  'snmp_port=s' => sub { $opts{$_[0]} = $_[1]; }
  'snmp_timeout=s' => sub { $opts{$_[0]} = $_[1]; }
  ...
}