If you are an experienced administrator, you can skip the following minilecture on root, terminals, and editors except to note that to install yum and for many, if not most, of yum's commands to work properly it is necessary to become root (the superuser). Privileged commands will generally be indicated by means of the `#' prompt in the examples.
If you are a linux user, you may have used root privileges only via a Graphical User Interface (GUI) tool. At this moment there is no suitable GUI for yum, so yum commands must be entered at a command line (terminal).
Ways of bringing up a terminal window vary a bit from system to system. On some a terminal might be available as a Gnome or KDE menu entry. On others it might be on the bottom task bar, or as a menu selection if you right-click and hold with the focus over the X background. Terminals might be named ``terminal'', or xterm, or rterm, or kterm. Nearly any of these will suffice, although I personally prefer plain old xterms.
To begin to work with many of the examples, you will need to start up a terminal and become root on the terminal. To become root, enter:
$ suand enter the root password when prompted to do so. The prompt should change from the usual default $ to the sharp sign `#'. Tradition holds that this is to remind you to be sharp as root.
Note Well: As the root superuser you can utterly destroy your system's linux installation with a single careless keystroke! Be very certain that you type things in correctly, especially if they involve wildcard characters such as * or ?.
You will also need to use some sort of editor to create and modify some of the configuration files mentioned in this article. Your GUI setup will likely have at least some editors, or you can use an old Unix standby such as emacs or vi from the command line. These tools are not terribly easy learn and instruction is well beyond the scope of this article. Seek help from man pages, online resources, or The Linux Documentation Project (linked elsewhere in this document).