Wall (Unix)
Template:Short description Template:Lowercase Template:Infobox Software
Template:Mono (an abbreviation of write to all) is a Unix command-line utility that displays the contents of a computer file or standard input to all logged-in users. It is typically used by root to send out shutting down message to all users just before poweroff.
Invocation
Template:Mono reads the message from standard input by default when the filename is omitted. This is done by piping the output of the Template:Mono command:
alice@sleipnir:~$ # `tty` to show the current terminal name
alice@sleipnir:~$ tty
/dev/pts/7
alice@sleipnir:~$ echo Remember to brush your teeth! | wall
The message may also be typed in much the same way Template:Mono is used: invoking Template:Mono by typing Template:Kbd and pressing Template:Keypress followed by a message, pressing Template:Keypress and [[End-of-transmission character|Template:Keypress+Template:Keypress]]:
alice@sleipnir:~$ wall
Remember to brush your teeth!
^D
Using a here-string:
alice@sleipnir:~$ wall <<< 'Remember to brush your teeth!'
Reading from a file is also supported:
alice@sleipnir:~$ cat .important_announcement
Remember to brush your teeth!
alice@sleipnir:~$ wall .important_announcement # same as `wall !$`
All the commands above should display the following output on terminals that users allow write access to (see mesg(1)):
Broadcast Message from alice@sleipnir
(/dev/pts/7) at 16:15 ...
Remember to brush your teeth!
See also
References
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