Tips from Perl SNMP and Expect project

First of all, a good place to obtain MIBs and query them is SNMP-Link: http://www.snmplink.org/OnLineMIB/.
To use Expect with Perl, a code snippet from Emulab snmpit tool:

    my $spawn_cmd = "telnet $self->{NAME}";
    my $exp = new Expect();
    if (!$exp) {
        # upper layer will check this
        return undef;
    }
    $exp->raw_pty(0);
    $exp->log_stdout(0);
    $exp->spawn($spawn_cmd)
    or die "Cannot spawn $spawn_cmd: $!\n";

    # have to send a newline to make login prompt come out
    $exp->send("\n");
    $exp->expect($CLI_TIMEOUT,
         ["login:", sub {
             my $e = shift;
             $e->send("admin\n");
             exp_continue;}],
         ["password:", sub {
             my $e = shift;
             $e->send($self->{PASSWORD}."\n");
             exp_continue;}],
         [timeout => sub {
             my $e = shift;
             $e->hard_close();
             die "timeout when connect to switch!\n";}],
         [qr/$self->{CLI_PROMPT}/, sub {;}]);

    # Disable paging in CLI output so that no "next page"
    # will bother us.
    $exp->send("disable clipaging\n");
    $exp->expect($CLI_TIMEOUT,
         [qr/$CLI_ERROR_PATTERN/,
          sub {
              my $e = shift;
              die "Incorrect command and result: ".$e->match().
              $e->after()."\n";}],
         [qr/$CLI_PROMPT/ => sub {;}],
         [timeout => sub {
             my $e = shift;
             $e->hard_close();
             die "timeout when connect to switch!\n";}]);