If you are talking to another Unix system, you can send and receive files with ~p (put) and ~t (take). These commands run cat(1) and echo(1) on the remote system to accept and send files. The syntax is:
~p <local-file> [<remote-file>] ~t <remote-file> [<local-file>]
There is no error checking, so you probably should use another protocol, like zmodem.