Linux and Unix write command
write sends a message to another user.
When you run the write command, the user you are writing to gets a message of the format:
Message from yourname@yourhost on yourtty at hh:mm ...
Any further lines you enter will be copied to the specified user's terminal. If the other user wants to reply, they must run write as well.
If the user you want to write to is logged in on more than one terminal, you can specify which terminal to write to by specifying the terminal name as the second operand to the write command. Alternatively, you can let write select one of the terminals; it will pick the one with the shortest idle time. This is so that if the user is logged in at work and also dialed up from home, the message will go to the right place.
The traditional protocol for writing to someone is that the string ‘-o’, either at the end of a line or on a line by itself, means that it is the other person's turn to talk. The string ‘oo’ means that the person believes the conversation to be over.
write user [tty]
|user||The user to write to.|
|tty||The specific terminal to write to, if the user is logged in to more than one session.|
Write a message to the user hope. After entering this command, you will be placed on a blank line, where everything you type will be sent to the other user (line by line). Typing the interrupt character (CTRL-C, by default) will return you to the command prompt, and end the write session.
write hope tty7
Write a message to the user hope on terminal tty7.
mesg — Control if (non-root) users can send messages to your terminal.
talk — Talk with other logged in users.
wall — Send a message to all logged-in users.
who — Report which users are logged in to the system.