SYNOPSIS  
  use Net::SSH qw(ssh issh sshopen2 sshopen3);
 
  ssh('user@hostname', $command);
 
  issh('user@hostname', $command);
 
  ssh_cmd('user@hostname', $command);
  ssh_cmd( {
    user => 'user',
    host => 'host.name',
    command => 'command',
    args => [ '-arg1', '-arg2' ],
    stdin_string => "string\n",
  } );
 
  sshopen2('user@hostname', $reader, $writer, $command);
 
  sshopen3('user@hostname', $writer, $reader, $error, $command);