Wall messages to server admins and users
From time to time it is important to let others know what you intend to do the server by way of maintenance to that server. It has some good points and some bad so not ideal to communicate with one another when working on the site together.
wall -- send a message to everybody's terminal.
wall [ message ]
Wall sends a message to everybody logged in with their mesg(1) permission set to yes. The message can be given as an argument to wall, or it can be sent to wall's standard input. When using the standard input from a terminal, the message should be terminated with the EOF key (usually Control-D).
The length of the message is limited to 20 lines.
Here is what is not said about wall, wall will interrupt any text or code you are working on to display the message required to be sent. Whilst it does not change the code itself it is none the less very distracting and forces you to close what your working on and restart. So general chit chat is a no no with this application. It is purely there as a means to communicate an urgent message to the users and administrators of a given server.
How to use
If you want to echo a message to the screen you would type
This in itself is utterly useless "wall" on the other hand expects the message to be pre written in message.txt and the contents passed to wall using a redirect thus:
Now we can take advantage of this syntax to send a message direct from the command line instead of inside a file.
Notice how we have combined the two commands into one using the pipe symbol "|" this is not a alpha character as such but can be called from the keyboard and looks like an elongated colon symbol.
Because this application has a tendency to interrupt anything the user is doing at the time, we don't recommend it use for anything other than an urgent request. Leave chit chat to things like irc or skype instead, irc you chat on via a server terminal window or skype a desktop application.