wall -- Command

Send a message to all logged-in users
/etc/wall

wall  types a  message to  every  user currently  logged into  the COHERENT
system, with the  exception of the sender.  It can  be used to inform users
of information of general interest; for example, that man has landed on the
moon, or that the system is going down in 15 minutes.

wall reads the message to be broadcast from the standard input until end of
file.   When  it  sends  the  message,  it  prefaces  it  with  the  herald
``Broadcast  message ...'',  which includes an  audible warning.   Only the
superuser should  invoke /etc/wall (to  override access protections  of the
target terminals).

Files

/etc/utmp -- Current users file
/dev/tty*

See Also

commands,
msg,
who,
write

Diagnostics

The message  ``Cannot send to user on ttyname''  indicates that wall cannot
write to the given user.

© 2012 by Stephen A. Ness