Introducing Unix

Every computer must have an operating system. Operating systems perform many functions; for example, they:

- Interpret keystrokes and deliver them to the computer
- Turn computer output into something you can read on your screen
- Control many computer processes, such as deleting, moving, copying, and renaming files

Macintosh computers use the MacOS operating system. Most IBM PCs and compatibles use Windows for their operating system. Unlike Windows or MacOS, Unix is an operating system that can run on many computers, although in slightly different forms.

On server computers, Unix is a powerful multi-user environment, allowing many people to share the computer. However, on a personal computer, Unix is generally used as a single-user environment.

Unix offers many advantages for different types of users. Many users learn Unix because of its following features:

- - Unix makes file sharing and information publishing easy
  - Unix allows the user to communicate with other people across a variety of applications
  - If you are using a slow modem (2400 bps or less), Unix is the main way to access network resources locally and from around the world

Unlike graphical or menu driven operating systems, Unix is a command-driven operating system. This means you must type in a special Unix code (or command) before the computer will know what action to perform.

Connecting to a Unix Computer

To practice the commands and concepts learned in this workshop, we will work on a remote Unix computer. We will do that through Secure Shell (SSH), a secure communications protocol that connects a local workstation to a remote computer (sometimes called a host). An SSH client is a program that establishes the connection between the two computers. Once connected, the client becomes a virtual terminal, allowing us to interface with the host from our workstation.

There are many applications which may use the SSH protocol to create such terminal connections. The Terminal application in MacOS uses it, and for Windows users the PuTTy applcation is currently recommended. The PuTTy application is available via:

https://iuware.iu.edu/

In order to make a connection to a Unix server, you will need to have an account on the server and you will need to know the host name. Since we also will be working with a partner during some of the exercises we will also need their username.

Please be sure you have all of the following information before continuing:

Host Name:	mercury.uits.indiana.edu
Your Username:
Your Password:
Partner's username:

NOTE: If you are using these materials in self-study mode, you'll want to make sure you have an account on Mercury. (KB DOC LINK HERE) For the partner exercises, use jump059 as your partner's username.

Now that you have your account information gathered, you are ready to start your SSH session.

Logging In Using Windows

Windows users will connect to the mercury server using the PuTTy application.

Step 1.Launch PuTTy.

The PuTTy Configuration window opens.

Step 2.To enter the host name in the Host Name (or IP address) field, type:

mercury.uits.indiana.edu

Step 3.To initiate the connection to the server,

Click

The first time you attempt to login to the mercury server, you may see a message indicating that the authenticity of the host can't be established because its security key is not in a list of accepted hosts.

Step 4.If necessary, to add the mercury security key to the list of hosts local database,

Click

A terminal window opens.

Step 5.To begin logging into your account, in the terminal window, type:

your usernameEnter

You are prompted for the password for that username.

Step 6.To complete the login process, type:

your passwordEnter

You are now logged into your account. You will see a command prompt in the terminal window.

Logging In Using MacOS

MacOS users will connect to the mercury server using the Terminal application. It is one of the default MacOS applications, and may be located in the Utilities subdirectory of the Applications folder. You can find it using Finder.

Step 1.Open the Terminal application.

Step 2.To begin logging into your account, in the terminal window, type:

ssh username@mercury.uits.indiana.edu Enter

Step 3.If necessary, to verify you wish to connect, type:

yes Enter

You will be prompted for your account password.

Step 4.To complete the login process, type:

your passwordEnter

You are now logged into your account. You will see a command prompt in the terminal window.

Using Customized Unix Environments

Some utilities and applications featured on your Unix account may have been custom created to make your account more user-friendly and easy to maintain. For example, system administrators may have created a setup program for you to run when you first log into your Unix account, which allows you to change certain system settings using a user-friendly interface. Other systems may include a menu which lists popular applications that you can run.

Today's workshop will not be using any special menus that may appear on the system. You can assume that anything you learn in this workshop will apply to your future experiences with Unix machines wherever you go, unless otherwise stated. This way you will not only be able to use self-explaining menu systems when you see them, but you will have some understanding of what is going on behind the menu.

Viewing the Unix Banner Page

System administrators often use a banner to convey important information to users about that system as soon as they log in. For instance, if the system was going to be down for a day, this is the place where you would find such a notice.

The banner page is usually only one screen long. However, if it is longer you may have to press Spacebar to move through the screens. After the banner page has been displayed, the system should automatically display a menu or exit you to a prompt.

NOTE: If you have a menu, you will need to select the proper menu item to "Exit to the Unix Shell". Once you've done this, you should see only a prompt.

You are now ready to begin working in your Unix account.