объединение и перенаправление сокетов (Concatenate and redirect sockets)
Статус выхода (Exit)
The exit code reflects whether a connection was made and
completed successfully. 0 means there was no error. 1 means there
was a network error of some kind, for example 'Connection
refused' or 'Connection reset'. 2 is reserved for all other
errors, like an invalid option or a nonexistent file.
