The Login Process

The first step is about to begin, so get yourself ready. You are either at the Unix console or you have remotely connected to your system using a terminal emulation application.

Terminal Emulation One of the most common ways to connect to a Unix system is remotely. The reason why Unix systems are commonly remote to you is because they are usually kept protected and secure in a designated location. You can connect to them with a service called Telnet, which provides terminal emulation. This is covered in greater depth in Lesson 18, "Networking and Security."

As mentioned before, once you attach to the system, you will be asked for your credentials, which consist of your username and password. After you supply this information, Unix will continue by loading your user environment. Your Unix system administrator will have already configured this for you, and he or she will have given you appropriate rights and permissions to do what you need to do on the system. After you successfully log in, you will see a command prompt awaiting your command. Now, before we continue, let's clarify something of extreme importance. There are two ways to log in to Unix: either via text-based login, which we will cover in the next section, or with a GUI, which will be covered after we discuss text-based login. Even if you log in via a GUI, you can still get to a shell prompt within the GUI. This will be explained later. What is important to remember at this time is that our goal is to get to the command line, even if you have to navigate a GUI-based login to get there.

Text-Based Login

Text-based login takes us right to where we want to go: to the command line or shell prompt.

Something that can be confusing to Unix learners is that text-based login screens vary between Unix distributions (also commonly nicknamed distros), and although login screens are becoming more similar, they are still different enough to cause annoyance to most new users. Most text-based Unix login prompts look like this:

 login: password: 

When you see the login: prompt, type your username and press return. The password: prompt appears immediately thereafter. When you have successfully typed in both your username and password, you reach what is called a shell prompt. This is the most common way you will see login and password prompts, and any deviations will be simple to figure out.

When logging in to your system, it's important to remember a few things that will most likely cause you frustration or stop you from logging in. These include the following:

• Ensure that case sensitivity is not an issue when supplying your credentials.

• Make sure you are supplying the correct credentials.

• Make sure that if you have supplied the correct credentials, your account settings are not an issue. Your account could be configured so that if you try too many wrong passwords, you are barred from attempting to enter any new ones.

• Make sure that you do not backspace, because in some distros of Unix, you will find that backspacing does not work. Type carefully to save time.

After you have completed the login process, you will be ready to take the next step and proceed to the next lesson. Before we move on, though, let's learn about KDE and the GUI-based graphical login process.

Secure Your Credentials When you are asked to enter your password, Unix is kind enough to block it out on your monitor from prying eyes. It does so to maintain security over the system so that your credentials do not fall into the hands of others who could impersonate you and cause damage to the system. Prying eyes can't see you type your password on the screen as you type it; they can watch what you are typing on your keyboard. This is a common practice, so be aware of it and keep your credentials safe. If you think that your credentials may have been compromised, ask your system administrator or help desk to change them immediately if you do not have authorization to change them yourself. Just like anything else in life, if you spend some time thinking of and considering security, the less likely you are to have a security issue.

Graphical Login

Throughout this first chapter you have heard about how to log in to Unix via text-based login. With KDE (which stands for K Desktop Environment), you have the option of graphically logging in to your system. Here, when your Unix system starts up, it goes through the same boot-up process until it gets to the login prompt. Instead of the text-based login screen, however, the X Window System environment launches. From this environment, the graphical environment or shell in which you will work is loaded. The most common graphical environment is KDE, although GNOME is also common; both are covered later in this chapter. To log in to Unix graphically, you will be presented with the same credential request, but instead of seeing it in the command line, you will see it in a dialog box. After you supply the correct credentials, you will be logged in to the system, and you can continue your work or lessons.

Consider a graphical login. Instead of sitting down at your Unix terminal, you may be sitting in front of your home PC with Linux installed. You boot up your system and are presented with a dialog box with the same basic information such as needing your credentials (username and password), but you may have other options available to you as well, such as the ability to change the session type. In any case, other than for the presence of a few commands that you can see graphically and manipulate with your mouse, text-based and graphical logins are still requesting the most basic of information, which is your username and password.

Keyboard Shortcuts When using Unix, you should get used to some new keyboard shortcuts because you will be working within the command line more and more. Knowing a few shortcuts can save you a lot of time when navigating the shell. Use the Tab key within the GUI to shift fields. For instance, after you type in your username, use the Tab key to get to the next field. This will allow your hands to remain on the keyboard and not have to reach for the mouse. This is one example of how you can save time while navigating not only Unix, but also the keyboard.