perl登录ssh

use warnings;
use strict;
use Net::SSH::Perl;my $host = '192.168.255.128';
my $username = 'root';
my $password = 'root';my $ssh = Net::SSH::Perl->new($host,port=>);
$ssh->login($username, $password);
my ($stdout, $stderr, $exit) = $ssh->cmd('ifconfig');
if($stderr){
print "Error:$stderr\n";
}else{
print $stdout;
}
exit $exit;