my @id_files = qw(/home/me/.ssh/id_rsa.pub);
my $ssh = Net::SSH::Perl->new( 'host', debug => 1, protocol => 2, identity_files => \@id_files );
$ssh->login()
my ( $o, $e, $ex ) = $ssh->cmd( 'uptime' );

##</code><code>##

host: Trying empty user-authentication request.
host: Authentication methods that can continue: publickey,keyboard-interactive.
host: Next method to try is publickey.
host: Trying pubkey authentication with key file '/home/me/.ssh/id_rsa.pub'
host: Will not query passphrase for '/home/me/.ssh/id_rsa.pub' in batch mode.
 Loading private key failed.