The write session is terminated by sending EOF, which can be done by pressing Ctrl+D. The tty argument is only necessary when a user is logged into more than one terminal.[4]
A conversation initiated between two users on the same machine:
^Unix Programmer's Manual(PDF) (1st ed.). Bell Labs. 3 November 1971. p. write(1). Archived from the original(PDF) on 9 July 2016. Retrieved 9 July 2016.