UGN Security

Messaging all users

Posted By: spectre

Messaging all users - 06/05/03 02:51 PM

Is there a command that I could use, as root, to message all the users connected to my system? I know that if you are going to perform a shutdown (shutdown -r now message), you can message all the users telling them "hey, I am going to shutdown now". But I simply just want to be able to send a message to everyone that says "hey, I am going to turn off the internet in 15 minutes".

Yeah. I searched google, but it was all trash. Any help? Thanks.
Posted By: sinetific

Re: Messaging all users - 06/05/03 08:25 PM

I forget how to send messages to all users

$wall or $/etc/wall (send a message to all users online)

$write user [tty] (send messge to a specific user)

$talk user [tty] (same as write)

$mesg y or n (turns messaging on or off for your user)

$who (displays who is logged on to what tty)

there are probably some more ways these are all i could think of.
Posted By: pergesu

Re: Messaging all users - 06/06/03 09:26 PM


[cammie:~] pergesu% man wall
WALL(1) System 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-

-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.

4th Berkeley Distribution June 6, 1993 4th Berkeley Distribution
I didn't get it to work though. Another option is writing a simple perl or shell script, that does "who", gets and parses the output, and iterates through the users and sends them messages. I don't know Perl, so I can't write it. But I'm sure it wouldn't be hard at all.
Posted By: Infinite

Re: Messaging all users - 06/06/03 09:36 PM

works fine for me.


I'm just to retarded to remember the -g before I specify a group to send to smirk

Posted By: pergesu

Re: Messaging all users - 06/07/03 12:53 AM

I got it too. On OS X you're supposed to specify a file on the command line. If you want it from the standard input, just hit enter, then type in all the text on one or several new lines, and hit ctrl+d.
Posted By: spectre

Re: Messaging all users - 06/07/03 04:56 PM

Tahnks for the info. I couldn't figure out for the life of me on how to do it. This works perfectly.
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