#!/usr/bin/perl
use strict;
use warnings;
use Net::SSH2;

my $ssh2 = Net::SSH2->new();
$ssh2->debug(1);
$ssh2->blocking(1);
$ssh2->connect('127.0.0.1', 22) # default port 22
    or $ssh2->die_with_error;
$ssh2->auth( publickey => "/home/user/.ssh/id_rsa");
$ssh2->check_hostkey('ask') or $ssh2->die_with_error;
$ssh2->disconnect();

__END__

$ perl test.pl
libssh2_knownhost_init(ss->session) -> 0x11b1a60
Net::SSH2::KnownHosts::DESTROY
Net::SSH2::DESTROY object 0x13cf7a0