Configuring GNU/Linux does not end when the installation CD ejects, nor even after the post-install wizard runs. While installation leaves you with a basic system, it does not leave you with an optimized system in which all your preferences and requirements have been taken into account. Given an operating system's size and complexity, you should not expect it to -- and finishing the install program leaves you in much the same position on Windows as well.
If you know anything about GNU/Linux, you may know that you do not need a defragger or to worry much about anti-virus software. But what else do you need to do? On that question, most distributions are largely silent, although the number of people who have installed their own operating system is only a minority of computer users. Nowadays, you cannot even assume that all GNU/Linux users have done it.
To fill that gap, here are nine steps you should take after installing GNU/Linux. They are based on far too many late nights tweaking far too many desktop computers in my own home. Following them takes time, but, if you do, you can help ensure that your use of your new operating system is more trouble-free and less frustrating.
New versions of free software programs are continually being released. For this reasons, the chances are strong that the CD or DVD image from which you installed is already obsolete. For this reason, your first step after installation should be to upgrade your system. Apart from your natural wish to have the latest toys, you will also be getting the latest security fixes. You'll find an update icon in the notification tray on your desktop panel that should be largely self-explanatory.
Just because GNU/Linux is virus free and securely designed doesn't mean that you should take chances. As soon as you've updated your system, the next step you should take is make sure that your system's security tools are working for you.
On Debian, Fedora, Gentoo, Mandrake, Red Hat, and SuSE, the single most important step you can take is to install and run Bastille. Bastille is a system hardener that teaches you at the same time, suggesting standard ways of securing your system and why you might want various options. Jay Beale, Bastille's creator, suggests that its options may be all the security you need.
However, if SELinux or AppArmor is available for your distribution, you might also consider using them for added security. You may lose a few percent of system performance by doing so, but less than running a virus-scanner in the background.
SELinux in particular, has a well-justified reputation for being hard to configure, but in some distributions like Fedora, it is a standard part of the install, with graphical tools to handle basic manipulations of it.
While you are thinking of security, if you are exchanging files with a Windows user -- or with a Windows installation on the same computer (see below) -- you might also want to install Clam Anti-Virus. Your GNU/Linux distribution won't need it, but the Windows installation might.
These days, GNU/Linux installation programs, especially those aimed at new users, usually detect much of your hardware, including your Internet connections. But for some reason, most installation programs (including Windows', last time I checked) omit printer configuration -- never mind that the average computer is connected to one.
Fortunately, printer configuration is easy these days. The tools you need are System -> Administration -> Printing in the GNOME menu, and Administration -> Printing in the KDE 4 menu. You will probably want to install as the root user so everybody can use the printer, although you do have the option of enabling a printer only for the current account in KDE. With either tool, all you need to do is plug in your computer, then follow the instructions.
If your printer is not listed, look it up in the Linux Printer Database. You may find information about other drivers that will get your printer working. For postscript printers, all you should need is to choose the generic postscript driver as you follow the instructions.
As on Windows, on GNU/Linux, you need to configure your email reader after installation, entering such information as your address, password, and your servers for sending and receiving mail. You can get this information from an existing operating system, or, if necessary, from your Internet Service Provider.