About man shutdown
at:
it indicates:
...
The first argument may be a time string (which is usually "now").
Optionally, this may be followed by a wall message to be sent to
all logged-in users before going down.
...
Note that to specify a wall message you must specify a time
argument, too.
...
Note this post is about the wall message to be broadcast to all the logged users.
Therefore using the following pattern as follows:
shutdown <time> ["something to share"]
Where <time>
can be +1, ... +5, ... +15, therefore from the +1
to +15
range - it as follows:
shutdown +1 ["something to share"]
...
shutdown +5 ["something to share"]
...
shutdown +15 ["something to share"]
I can confirm the other users that are logged receive - appears in their tty
- the broadcast message (including or not the custom message according the case). Therefore as the documentation indicates, the message is broadcast. Until here no reason to create this post.
Situation: the reason, I did realise - if <time>
is equals or greater than 16 minutes - used through either +16
or hh:mm
the message is not broadcast to the other logged users in their tty
. For example if date
command returns 00:10
then with shutdown 00:26 ...
this situation happens. Of course, if is used shutdown 00:15
all work as expected.
Question
- Why the wall message is not broadcast to all logged users if the time is equals or greater than 16 minutes? - Is it normal or is a bug?
Through either the man shutdown
or shutdown --help
theoretically the wall message must be always broadcast to all the logged users, it does not matter the range of time about "from now" +15, +20 etc ...
Note I have this situation in many Virtual Machines - for different hosts - for Ubuntu Server 20.04
shutdown +20
and wait five minutes? I haven't tried that in a while so not sure, but I seem to recall it walls more often when time is running out and more rarely (or not at all) when there's more time left.