This is a port of openbsd cu(1) to Linux.

cu is used to connect to another system over a serial link.
In the era before modern networks, it was typically used to
connect to a modem in order to dial in to a remote host.
It is now frequently used for tasks such as attaching to the
serial console of another machine for administrative or
debugging purposes.

When working with an embedded Linux box, it is useful to setup the tty
device in embedded os with the rows and columns of the terminal in the
host os. The termsize[1] script by Akkana Peck is quite useful[2] for
this task.

[1] https://github.com/akkana/scripts/blob/master/termsize
[2] http://shallowsky.com/blog/hardware/serial-24-line-terminals.html