WALL(1) NetBSD 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 super-user can write on the terminals of users who have chosen to deny messages or are using a program which automatically denies mes- sages. -g Send messages to users in this group. This option may be speci- fied multiple times, and any user in any of the specified groups will receive the message.
mesg(1), talk(1), write(1), shutdown(8)
A wall command appeared in Version 7 AT&T UNIX. Support for -g was added in NetBSD 2.0 (from OpenBSD 2.0). NetBSD 9.0 March 27, 2003 NetBSD 9.0
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