Network Console on Acid

nca (Network Console on Acid) connects a pseudo terminal to the consoles' virtual terminals (/dev/tty0, etc.), allowing a remote user to read and write directly to the console. It is supplied with a version of OpenSSH that is hacked so that one can connect to a Linux server and run nca very early in the boot up sequence (immediately after the root filesystem has been mounted read only). It's the next best thing to a serial console for fixing boot-time problems remotely.