Most of this. It uses ptrace() to connect to the target and then make the target make specific system calls and ioctl()s on various fd's. I bet it could be port

Most of this. It uses ptrace() to connect to the target and then make the target make specific system calls and ioctl()s on various fd's. I bet it could be ported to other unixes (assuming they have equivalent tty syscalls and ioctl's), but you'd have to change a lot of the details. If someone wants to try a port to, say, a BSD that abstracts the syscalls and ioctls into a platform-specific way, I'd be happy to take a look.