Introduction to Linux, Netscape, and Emacs

The Login Process:

Linux can be accessed in both the first floor general-use lab in Trexler and in the 2nd floor MCSP lab. The machines in these labs run Windows XP. Log into Windows as usual, then look for an icon on the desktop that says XWin to Riddler. Double click on this icon; you should get a "Welcome to riddler.roanoke.edu" login screen. To log in:

Type your user name and press Enter
Type your password (the same password you use to access mail) and press Enter

If you have problems logging in, make sure that you are entering the correct user name and password. If you ever have password problems, go to Information Services on 3rd floor Trexler for assistance.

The first time you log in, you may see a screen that asks you whether you want the default setup or not. If you get this screen, click on the option for the default setup.

You are now logged into Riddler, the Linux server. You should see a desktop environment similar to Windows. This is GNOME, one of the most popular desktop environments for Linux. By default, GNOME uses the window manager Sawfish, but we will loosely refer to everything in the windowing environment as GNOME. Here are some basics for getting around in GNOME:

The bar across the bottom of the screen is the GNOME Panel. Just as you access programs in Windows from the Start menu, you can access programs in GNOME by clicking on the FOOT icon at the left end of the Panel, then choosing options such as Programs from the menus.
A GNOME Start Here window is probably displayed on your screen. Another way to access programs and settings on the system is through this window (rather than the panel).
A taskbar is in the middle of the panel. It contains an icon for each window that you have open on the desktop. (It should show the Start Here window if you left it open). These are similar to the icons that you see on the taskbar in Windows. On the far right of this bar is a small box that represents your desktop. GNOME lets you manage multiple desktops.
There are a few icons on the panel. You can hold your mouse over an icon to get information about it. One of the icons is a red animal (or monster!) head -- this is Mozilla, a Web browser. Another is a terminal icon. Click on this to launch an X-terminal window, or xterm. An xterm is essentially a new login environment. In fact, when you open an xterm you are logging into the system again. Linux has a command named finger that lets you see who is logged onto the system. Type finger at the xterm prompt ($); you will see lots of people logged on (at least while you're in lab), including you. You can execute any shell command from an xterm -- more on shell commands later. Leave the xterm open -- we'll come back to it soon.
Two other programs you will use often are Emacs (a text editor) and Netscape Communicator. It's useful to have icons for these on the Panel, so we'll put them there now. Click on the FOOT icon then choose Programs, then go to the Applications item. Another menu should appear, with Emacs near the middle of the lower part. Right click on Emacs and choose "Add this launcher to Panel." (If you accidentally open an Emacs window, click on the X in the upper right hand corner to close it.) The Emacs icon should appear on the Panel. Now go back to the Internet item on the Programs menu; right click on Netscape Communicator (not Netscape Navigator) and add it to the Panel as well.
To remove an icon from the panel right click on the icon then choose the "Remove from panel" option. Try this by removing the lock icon.
GNOME has another X-terminal called Rxvt that you may prefer to the default that you opened earlier (I do!). Put an icon for it on your panel (click on FOOT then Programs, then Utilities. Now right click on Rxvt). Click on the icon to open the Rxvt terminal window.

Managing GNOME Windows

The windows you will use under GNOME will feel much like those under Windows 98, 2000, NT, or XP although a few things are different. Click on the xterm icon on the Panel to get another xterm window, then use your two windows to get comfortable with these basics:

The Taskbar: First, notice that there are now two icons on the taskbar for xterm windows plus one for rxvt and one for Start Here. Open two more xterm windows and you will see that only one icon for the xterms appears on the taskbar, this time with a 4 in parenthesis. If you have 4 or more of a given type of window open, only one icon appears on the taskbar for the type of window, and it shows how many such windows are open. If you click on this icon, you will see a list of the individual windows and you can select one.

Moving Windows: To move a window, move the mouse pointer over the title bar of the window, then hold down the left mouse button down while you drag the window to the location that you desire. Then release the mouse button and the window will be moved. Alternatively, you can hold down ALT and then click anywhere in the window to drag it to a new location. This is particularly handy if the title bar is not visible.

Activating a Window: The window that has a blue title bar and border is the active window. Only one window can be active at a time. To make another window active, click inside that window or on its titlebar. This will both activate the window and bring it to the front. The usual way to cycle through windows in Gnome is by pressing Alt-Tab (hold Alt down, then press Tab), just as in Windows XP. However, since you are logging in through Windows XP, this will just take you out of Linux and back to Windows. (Try it by pressing Alt-Tab. Once you're in Windows, you can get back to Linux by clicking on the Cygwin icon on the task bar.) You can modify your settings to make C-Tab (Ctrl-Tab) cycle through windows instead as follows:

Click on the FOOT and choose Programs|Settings|Desktop|Window Manager.
Click on Run Configuration Tool for Sawfish.
Choose Bindings from the list.
The second item in the list on the right side should say M-Tab for Cycle Windows. (M stands for "Meta", which is the Alt key for us.) Select this item, then click Edit.
In the box at the top, change M to C. It should now say C-Tab.
Click OK on each window (three times) until you're out of the Window Manager.

Now try C-Tab; it should cycle through the windows.

Resizing Windows: To resize a window, point to a corner, hold down the mouse button and drag the corner. The middle button (with a picture of a half-filled-in square) in the upper right hand corner can also be used to maximize the window (make it fill the whole screen) and then to change it back to the original size.

Minimizing Windows: To minimize a window, click the leftmost button (with a picture of a line at the bottom) in the upper right hand corner of the window. Note that for minimized windows the icons on the taskbar at the bottom of the screen are greyed out.

Closing Windows: To close a window, click the rightmost button (with a picture of an X) in the upper right hand corner of the window. Generally you won't want so many of the same type of window open so close some of the terminal windows.

Using Multiple Workspaces: GNOME allows you to have several different workspaces open simultaneously. For example, later in the course you may want to have one workspace with a terminal window where you are working on your personal web pages and another workspace with a terminal window to work on lab exercises. Or, you may want to have your browser open in one workspace, the emacs editor in another, or whatever. The right side of the GNOME panel shows your workspaces (a 2 by 2 grid -- and in each rectangle smaller rectangles indicating windows open in that workspace). At this point you should have one workspace open with a couple of windows open in it. To change workspaces, just click on the rectangle.

Moving Around the Linux File System

Now that you can get around the window environment, let's take a look at an xterm. Click on one of the terminal windows (either rxvt or the default xterm -- from here on we will use "xterm" to mean either) to activate it. The program running in the xterm is called the shell. The shell lets you issue commands to the Linux operating system and work with files. Refer to the handouts on the shell commands and Unix files given in class as you follow the directions below to move around the file system. Pay attention to what happens on the screen after each command.

Type pwd to determine your present working directory.
Type cd / to change directory to the system root, /.
Type ls to see a listing of the files in the root directory. You should recognize some of the directory names such as etc, bin, and home. Note that in a color xterm, directories appear in blue.
Type ls -l (that is an el, not a one) to see a "long" listing of the files. You will see information about each file, including the permissions. Note that one of the files in the root directory is the directory bin.
Type cd bin to change to the bin directory.
Type ls to see a list of files in bin. Recall from the take home portion of the lab that system commands are usually in bin directories. You should recognize the names of some of the Unix shell commands (such as cp and ls). The files you see in this directory are the executable versions of the commands; that is, they contain the instructions, in machine code, for executing these commands. (Executable files are in green; links are in light blue.)
Type ls -l cp to determine the permissions on the command cp (-l is el not one). Look in the file system handout to see how to interpret what you see. Note that everyone has permission to read and execute this file; the owner (root) has write permission.
Type cd ~username (for example, if your user name is bozo type cd ~bozo) to go back to your home directory. (OR just type cd with no argument -- that always takes a user home!)
Type cd .. to move up one level in the directory tree to /home/students. (Check that you are there by typing pwd.)
Type ls to see a list of all the student home directories on the system.
Get back to your home directory. (There are several ways to do this -- choose the fastest!)

Setting Up Your Directory

Now we'll set up your directory with some subdirectories and copy some files into them. Do the following:

Type ls to get a list of the files and directories in your home directory. (There may not be any!)
Type ls -a for a list of all files and directories in your directory. (You should see some system files with names beginning with a period -- these were created and are used by the system. They start with a . so they won't be confused with user files.)
Make a directory for this class named cpsc120 by typing mkdir cpsc120 From now on, you should use this directory to store the files you create in this course.
Type ls again to see the list of sub-directories in your home directory. The new sub-directory cpsc120 should now be in this list.
Move into this new cpsc120 sub-directory by typing cd cpsc120
Confirm you are in this new sub-directory by typing pwd
Now create a directory named labs and move into this labs directory.
Now create another directory (as a subdirectory of labs) named lab0 and again move into this directory.
By typing pwd here you should see that you are now in:
/home/students/username/cpsc120/labs/lab0
Now copy the file UnixQuestions from the cpsc (Computer Science) home directory to your present directory by typing:

cp ~cpsc/UnixQuestions .

(Don't forget the period at the end of this line -- and you need a space between UnixQuestions and the period -- to indicate you want the file copied to your current working directory!!)
Use the more command to see the contents of the file UnixQuestions by simply typing more UnixQuestions
Go back to your cpsc120 subdirectory. You should have one subdirectory at this point -- one named labs. Now create another one named projects.

STOP!!! Before going further have the instructor or a lab assistant come over and check to see that you have your directory set up correctly. You will be asked to go to your home directory, show a listing of the files there, then go down into the subdirectories you have created and show what is there.

Emacs

Launch Emacs You can do this either by clicking on the Emacs icon (a head with horns) on the Panel or by typing the command emacs & in a shell window.

The X-windows version of Emacs has a menu bar that you can see at the top of the editor. These are pull down menus that you can use to perform many commands. However, every command in a pull down menu can also be executed in Emacs using an Emacs function and special keystrokes. Once you become proficient at using Emacs you will probably prefer the keystroke method of giving commands.

Editing an existing file

We'll first use Emacs to edit the UnixQuestions file. To open this file in your lab0 subdirectory do the following:

In your Emacs window, use the pull down menu item Open File... under the Files menu, or use the key stroke C-x C-f (the C stands for the Control ctrl key -- hold it down then press the x key, release the x then press the f).
Look at the bottom of the window in the minibuffer and you will see the words Find File: followed by the path of the directory you were in when you started Emacs. You need to specify the path for the file you want to open to edit. If you have correctly created your subdirectories the full path should be /home/students/yourUsername/cpsc120/labs/lab0/UnixQuestions or ~/cpsc120/labs/lab0/UnixQuestions which works because ~ stands for your home directory. You probably already see "~/" in the minibuffer so you just need to add the rest of the path to it. Press ENTER after you type in the file name and you will be in a buffer containing the file. (The file name corresponding to the buffer will appear near the bottom of the window on the status line.)

Now, you are ready to edit. As in a word processor you may move around in the buffer with the arrow keys and with the mouse. Unlike a word processor however you should press the ENTER key when you are at the end of a line. Text editors typically do not provide the same automatic line wrap features that word processors do (though Emacs provides some).

Now type in the answer to each question immediately following the question.

Save the file by typing C-x C-s (remember the C stands for the control ctrl key -- hold it down then hit the x key, then release it and hit the s key) OR choose File, then Save (current buffer) from the menu.

Now go to the shell window and use the nenscript command to print out your answers. The command is as follows:

nenscript -2rG -p- UnixQuestions | lpr -P lab-mcsp -h
NOTE: The | (between UnixQuestions and lpr) is a pipe, which is the key just below the backspace key -- backslash is the other character on the key.
The document will be printed on the lab printer.

Netscape Communicator

Now we'll go through a brief introduction to Netscape Communicator which we will use for Web browsing and mail.

Start up Netscape by clicking on the Netscape icon on the Panel or by typing netscape & at the command line in one of your xterm windows. (The & at the end of the command tells the shell to run the Netscape program in the background so that the shell can be used to perform other tasks at the same time that the Netscape window is open.) Click through any dialogs that appear the first time you run Netscape. You may get an error window about disk caching; click ok.

You should see before you in the browser's main viewer a page about Red Hat Linux. Clicking on Home will take you to your home page (the page that is displayed when you start up Netscape), which by default is probably the Roanoke College home page or the Netscape page. We'll change this later in the lab if necessary.

At the top of the Netscape window you see a menu bar with several options including a File option that lets you do things such as open files and print files, and an Edit option that, among other things, lets you configure your personal preferences such as what you want your home page to be. Help can also be found on the right end of this menu bar. Below the menu is a series of buttons that can guide you through the documents you visit on the Web. The Home button always takes you back to the home page you have specified in your settings. Other buttons let you go backwards and forwards in your document history for this session, reload your document, print the current document, search the current document and stop the document from loading. At the end of this line, you see a picture of an N. Whenever this N is animated with shooting stars, a document is currently being loaded.

The line below the row of buttons contains the location of the document you are currently viewing. Each document ("page") on the Web has a location (in a file on a computer on the Web) which is specified by a URL (Uniform Resource Locator). A URL is basically an address of a page. The URL for the Roanoke College home page is http://www.roanoke.edu. If you know the URL of a page you want to see, you can type it in the location box (then press ENTER).

On the next line, you see several buttons that will automatically take you to locations that can help you navigate and find documents on the Internet.

Moving Around in Netscape -- "Surfing the Web":

There are several ways for you to access different pages on the Web:

You may specify the URL (either type it in the Location box, or choose File, Open Page from the menu, then type it in);
Most pages have links to other pages. Clicking on a link sends you to the other page. (Links on a page are represented, in general, by text that is underlined, or icons that are surrounded in blue.)
Use addresses you have saved in bookmarks.
Use the buttons that send you to the search tools (such as Yahoo and Google).

If you have never used Netscape you should try out some of the options above at some point.

For now go to the home page for this class by typing the address

 
http://cs.roanoke.edu/~cpsc/CPSC120A (Dr. Bloss's class)

 
http://cs.roanoke.edu/~cpsc/CPSC120B (Dr. Ingram's class)

into the location box then pressing ENTER. Bookmark this page by clicking on the Bookmark icon, then choose Add bookmark. Click on bookmark again and you should see that this address is there. In the future when you want to visit this page just use your bookmark. This is the page that you will use throughout the term to get information related to the course.

Changing your Password:
The following are instructions for changing your email/Linux password. Note that changing this will change the password you use to read your e-mail, even under Windows. If you are still using the default password given to you by Information Services, change your password now (otherwise you don't need to):

Go to http://sysmgr.roanoke.edu in your web browser.
Log in with your username and your current email/Linux password.
Select Change Password from the menu on the left.
Enter your current password and your desired new password twice, then click the Change Password button.
You should receive a message that your password has been successfully changed.
Log out of the system by clicking Log Out at the top of the menu on the left.

Netscape Mail:

In this course you will often need to use the Linux version of Netscape to send mail to your instructor. You may also want to use this to read your mail. The primary mail server at Roanoke is a Dell computer named imap. All student mail addressed to username@roanoke.edu goes to imap. Netscape on Linux can be set up to use imap so that mail addressed to username@roanoke.edu can be read from Linux. Options for setting up your mail and other browsing features are under the Edit option on the main window. We'll now look at your current preferences and change any that need to be changed.

Do the following:

Click on Edit from the menu then on Preferences.
You should see a window with a list of categories on the left side. Click on the Navigator category.
In the box for the home page location type in www.roanoke.edu if it isn't already there. This makes the Roanoke College home page your home page (it is ok to make your home page something else!).
You need to change a few items in your mail preferences as follows:
- Choose the category Identity under Mail and NewsGroups (If you don't see Identity click on the little triangle beside Mail and NewsGroups. This will show you a list of options including Identity and Mail Servers.)
- Type your full name in the "Your Name:" box.
- Type the address username@roanoke.edu (use your own username!) in the Email Address box.
- Now click on the Mail Servers category. In the Outgoing (SMTP) server box type in smtp.roanoke.edu
- In the Outgoing mail server username box, type your username.
- In the Incoming server box click on the server listed (if any). Click on delete to remove this server. Then click on the add button. Under the General tab, type in imap.roanoke.edu for the server, choose IMAP as the server type, and put your username in the username box. On the IMAP tab, choose "Move Deleted Messages to the Trash folder".
- Click on OK.
(NOTE: SMTP (Simple Mail Transport Protocol), is a protocol for sending mail and IMAP (Internet Message Access Protocol) is a protocol for receiving mail. Protocols are just sets of rules computers use when they exchange information, such as mail. The HTTP, (HyperText Transport Protocol), for another example, is the protocol that computers use to exchange Web pages. Protocols are what make the Internet work so we will be learning more about them during the term.)
Click on OK when you are done.
Now click on the HOME button to display the Roanoke College home page (if it isn't already there).

Getting into Mail: You can get into mail either by choosing Communicator, then Messenger or by clicking on the mailbox icon at the bottom right-hand corner of the window. You will need to enter your IMAP mail password (this is the same email password you have been using, which is also your Linux password) before you can access your mail.

Common Netscape Mail Functions:

The Get Msg button is used to check your mail on the server, and get the mail if you have any new mail.
The New Msg button is used to send mail. When you press this button a mail composition window will open. You need to enter such things as the e-mail address of the person that you are sending to, as well as, the subject of the mail. The bottom window is used to type your mail message.
The Reply button is used to reply to the mail currently showing in the mail viewer window. You will be given the choice of sending a reply to the sender of the message or to ALL of the people who received the message (if you use this button to reply to a message that was sent to everyone on campus, your reply will go out to everyone so be careful about using this option!).
The Forward button will forward the current mail to an e-mail address.
The Delete button is used to put the current message in the Trash folder. You should periodically empty the trash folder (an option under the File option on the menu).

Mail me a copy of your UnixQuestions file as follows: Go to your Netscape mail window (it should still be open -- if not, open it) and press the New Msg button. Put bloss@cs.roanoke.edu or ingram@cs.roanoke.edu (depending on which class you're in) in the To box. Now press the Attachment button. Choose File, then either choose the correct directory and file from the list (the file you should mail is the one named UnixQuestions) or in the selection box, type in the full pathname of your executable file. Press the Attach button then the Send button.

Close Emacs and Netscape.

Exiting an X-terminal: To exit an xterm, type exit at the command prompt. (NOTE: You can also exit by clicking the X in the upper right hand corner of the window, as in Windows. It is a good idea to get in the habit of exiting the window or a program within a window with the exit command instead of destroying it with the X. Though most programs should respond appropriately to your clicking the X, destroying windows can sometimes make you lose information that you wanted to save. For example, if you are editing a file, and use the destroy button, you may lose unsaved data.)

Exiting GNOME

To exit GNOME, click on the FOOT icon on the panel and choose "Log Out", then select Yes at the "Really Log Out?" window. This will take you back to Windows XP; be sure to log out of here too.