Command:   write - send a message to a logged-in user
Syntax:    write [-cv] user [tty]
Flags:     -c  Use cbreak mode
           -v  Verbose mode
Examples:  write ast                # Send a message to ast
           write ast tty00          # Send a message to ast on tty00

     Write lets a user send messages to another  logged-in  user.  Lines
typed  by the user appear on the other user's screen a line at a time (a
character at a time in the case of cbreak mode). The file  /usr/adm/wtmp
is  searched  to  determine  which tty to send to. If the user is logged
onto more than one terminal, the  tty  argument  selects  the  terminal.
Type CTRL- D to terminate the command.  Use ! as a shell escape.