Manual pages › System administration commands (1M)

wall(1M)

write to all users

From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.

NAME

wall - write to all users

SYNOPSIS

/usr/sbin/wall

DESCRIPTION

wall reads its standard input until an end-of-file. It then sends this message to all currently logged-in users preceded by:

Broadcast Message from ...

It is used to warn all users, typically prior to shutting down the system.

The sender must be super-user to override any protections the users may have invoked [see mesg(1)].

wall runs setgid() [see setuid(2)] to the group ID tty, in order to have write permissions on other user's terminals.

wall will detect non-printable characters before sending them to the user's terminal. Control characters will appear as a `^' followed by the appropriate ASCII character; characters with the high-order bit set will appear in meta notation. For example, `\003' is displayed as `^C' and `\372' as `M-z'.

FILES

/dev/tty*

NOTES