Wall (Unix)
# Wall (Unix)

wall (an abbreviation of write to all) is a Unix command-line utility that displays the contents of a computer file or standard input to all logged-in users. It is typically used by root to send out shutting down message to all users just before poweroff.

## Invocation

wall reads the message from standard input by default when the filename is omitted. This is done by piping the output of the echo command:

The message may also be typed in much the same way cat is used: invoking wall by typing wall and pressing ↵ Enter followed by a message, pressing ↵ Enter and Ctrl+D:

Using a here-string:

Reading from a file is also supported:

All the commands above should display the following output on terminals that users allow write access to (see mesg(1)):

