How to talk with other users connected to the Server

To communicate with another user who is connected to the same server via SSH, you can use several command-line utilities available on most Unix-like systems. The most commonly used commands for sending messages to other users on the same server are write, wall, and talk. Here’s how to use each of them:

1. Using the write Command

The write command sends a message to another user who is logged in by specifying their username and the terminal name (if they are logged in multiple terminals). You can see the terminals with the who command.

who

• This command shows a list of all logged-in users, their terminals, and other login info.

• Send a message:

write username tty

• Replace username with the user’s username and tty with their terminal name from the who output. After executing the command, you can start typing your message. Finish by pressing CTRL+D to end the message.

2. Using the wall Command

The wall (write all) command sends a message to all logged-in users. This is particularly useful for sending system-wide notifications.

• Send a broadcast message:

wall "Your message here"

• Simply type wall followed by your message enclosed in quotes. You might need superuser privileges depending on your system’s configuration.

3. Using the talk Command

The talk command allows a two-way interactive communication between two users.

Initiate a talk session:

talk username [tty]

• Replace username with the user’s username. The tty is optional if the user is logged in at more than one terminal. The user on the other end will see a message asking if they accept the talk request.

4. Using mesg Command

Before using write or talk, it’s good practice to check if the user has allowed messaging through the mesg command. Users can control whether they receive messages from other users with this command.

• Enable or disable receiving messages

mesg y  # Enable
mesg n  # Disable

5. Examples:

Here is a practical example of how to use these commands:

1. Check who is online:

who

2. Send a message using write:

write johndoe pts/1

3. Broadcast a message using wall:

sudo wall "Server will restart in 10 minutes."

4. Start a talk session:

talk johndoe pts/1

Remember that for write and talk, the user must have their message setting enabled (mesg y). These methods are straightforward for quick and direct text-based communication on servers where multiple users are logged in via SSH.