Keeping Users Informed

One of your primary responsibilities as a system administrator is communicating with system users. You need to make announcements, such as when the system will be down for maintenance, when a class on some new software will be held, and how users can access the new system printer. You can even start to fill the role of a small local newspaper, letting users know about new employees, RIFs, births, the company picnic, and so on.

Different communications have different priorities. For example, information about the company picnic in two months is not as time sensitive as the fact that you are bringing the system down in 5 minutes. To meet these differing needs, Linux provides different ways of communicating. The most common methods are described and contrasted in the following list. All of these methods are generally available to everyone, except for the message of the day, which is typically reserved for Superuser.

write

Use the write utility (page 150) to communicate with a user who is logged in on the local system. You might use it, for example, to ask a user to stop running a program that is bogging down the system; the user might reply that he will be done in 3 minutes. Users can also use write to ask the system administrator to mount a tape or restore a file. KDE and GNOME open a new window when they receive a message.

wall

The wall (write all) utility effectively communicates immediately with all users who are logged in. It works similarly to write, except that users cannot use wall to write back to only you. Use wall when you are about to bring the system down or are in another crisis situation. Users who are not logged in will not get the message.

Use wall while you are Superuser only in a crisis situation; it interrupts anything anyone is doing.

Email

Email is useful for communicating less urgent information to one or more systems and/or remote users. When you send mail, you have to be willing to wait for each user to read it. The email utilities are useful for reminding users that they are forgetting to log out, their bills are past due, or they are using too much disk space.

Users can easily make permanent records of messages they receive via email, as opposed to messages received via write, so they can keep track of important details. It would be appropriate to use email to inform users about a new, complex procedure, so each user could keep a copy of the information for reference.

Message of the day

Users see the message of the day each time they log in in a textual environment. You can edit the /etc/motd file to change this message as necessary. The message of the day can alert users to upcoming periodic maintenance, new system features, or a change in procedures.