wall

Write a message on the terminals of users currently logged in. More information: https://manned.org/wall.

• Send a message:

wall {{message}}

• Send a message to users that belong to a specific group:

wall {{[-g|--group]}} {{group_name}} {{message}}

• Send a message from a file:

wall {{file}}

• Send a message with timeout (default 300):

wall {{[-t|--timeout]}} {{seconds}} {{file}}