カテゴリ:

If you are root user, you could send message to all users who logged in with wall command.

root user

# wall "We will have a meeting tomorrow noon."

Broadcast message from root (pts/0) (Wed Feb 6 19:06:05 2008):

We will have a meeting tomorrow noon.

user

$
Broadcast message from root (pts/0) (Wed Feb 6 19:06:05 2008):

We will have a meeting tomorrow noon.