wall
Send a message to all logged-in users
TLDR
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]
SYNOPSIS
wall [options] [message]
PARAMETERS
-n
Don't include banner
-t TIMEOUT
Timeout for writing to terminals
-g GROUP
Send to group only
DESCRIPTION
wall displays a message on the terminals of all currently logged in users. The message can be given as arguments or read from standard input. It's commonly used by system administrators for announcements.
CAVEATS
Users can disable with mesg n. Message limited in size. Requires write access to terminals.
