OpenBSD manual page server

Manual Page Search Parameters
WALL(1) General Commands Manual WALL(1)

wall —
write a message to users

wall [-g group] [file]

wall displays the contents of file, or, by default, its standard input, on the terminals of all currently logged in users.

Only the superuser can write on the terminals of users who have chosen to deny messages or are using a program which automatically denies messages.

The options are as follows:

group
Send messages to users in this group. This option may be specified multiple times, and any user in any of the specified groups will receive the message.

Since the sender's locale(1) need not match the receivers' locales, wall deliberately ignores the LC_CTYPE environment variable and allows ASCII printable and space characters only. Non-printable characters and UTF-8 characters are replaced with question marks.

mesg(1), talk(1), write(1), shutdown(8)

A wall command appeared in Version 7 AT&T UNIX.
May 8, 2016 OpenBSD-current