	Department of Engineering

University of Cambridge > Engineering Department > computing help

Introduction for New Users

Cambridge University Engineering Department
Teaching Workstations
Roberto Cipolla, Richard Prager, Tim Love (July, 2006)

This document describes how to log on to the teaching system and perform simple file manipulation using X File Explorer. Common tasks like printing, editing, getting help, accessing the World Wide Web and using e-mail are also addressed. An enhanced version of this document is online in the help system.

Getting Started

Here we describe how to log on and perform simple file manipulation in the windowing environment. Using this simple environment you will be able to use the Unix operating system in a straightforward way.

To start with, the computer will present you with a login window. If the screen is completely black then move the mouse slightly; this will turn off the screen saver.

Make sure that This machine is highlighted.
Type your username (your CRS ID) and press the Return key. If you don't know your user identifier it can be found on the notice boards near the door to the main computer room. If in doubt ask a demonstrator or one of the operators in the machine room at the west end of the DPO.
Type in your CUED password (not your hermes password). First year students should have chosen a password during registration at the start of term. Other students should use their old password. When you type your password it will not be echoed to the screen. If you cannot remember your password, or it does not work, ask one of the operators. Unix is case sensitive, so make sure that ``Caps Lock'' is not set.
If there are system announcements a yellow window will appear in the bottom-right corner of the screen. Read the messages then press the Return key while the mouse pointer is in the yellow window. Once you have logged in successfully a text window will appear and you will get a prompt something like:
tw400/ab123:

If you are doing a practical you should now consult your main practical handout to see if you are required to use a special command (like `start camclay' or `start 1AComputing').

Icons and files

Your Home Folder

Next, we are going to start X File Explorer. Click on the start

button at the bottom-left of the screen and choose X File Explorer. The icons you initially see in this Xfe window represent files or collections of files in the part of the file system that belongs to you.

Creating a New File

To create a new file, choose the New File option from the File menu. Call the file sports.

When you come to name files yourself try to use only letters and digits --- no spaces or punctuation characters (except for full stops). If you are used to using PCs it is also worth noting that Unix distinguishes the case of characters in file names. The file Sports is not the same file as sports.

Copying Files

To copy the sports file hold the Ctrl button down while dragging the file elsewhere in the window. You will be prompted to give the new file a name. The name starts with the folder's name. Append it with /activities (note the '/' character) and click on the Accept button.

Deleting Files

Make another copy of sports called doomed. We will use this file to practice deleting! First select the doomed file by clicking on it. Then use the Delete menu item in the File menu. A new box will appear. Click on the OK option and the file will disappear from your directory.

Multiple File Selection

To select several files at once (so you can move them all together, for example), click on them while holding down the Ctrl key.

Folders

Creating a New Folder

Imagine that the sports file contains a list of the sports you like playing and the activities file contains a list of all the other leisure activities you enjoy. They are rather out of place among all the other files in your home directory which are currently mostly special user configuration files.

It would be nice if you could create a separate place to put sports and activities. This is what a folder is for. Folders (e.g. your home folder) can contain files and other sub-folders.

Choose the New Folder option from the File menu. Call the folder clump. Note how the icon of this folder looks different to ordinary file icons.

Double click on this new icon to open it out. You will see a folder just like your home folder, only almost empty. There will be one icon present, called `..' (pronounced `dot dot'). This refers to the folder's parent, in this case your home folder.

The underlying structure is that all the folders are arranged in a tree and each one contains icons telling it:

The parent folder (they only have one parent). This is the `..' icon.
Which (if any) folders are its children.
Which (if any) files it contains.

Note that the full name of the folder you're now looking at is shown near the top of the window.

Now double-click on the `..' icon. This will open out your home folder again because that is clump's parent.

Moving and Copying Between Folders

Now we'll try moving the sports files into the clump directory. If you drag the sports icon onto the clump icon and click on the Accept button when asked to confirm, your file will have moved into the folder. If you want to copy the file, leaving the original intact, then drag while pressing down the Ctrl key.

You may need to use the Refresh option of the File menu to update the window.

Window management

When you have lots of windows you need to be able to manage them.

Moving - you can drag a window around using its title bar.
Resizing - you can drag a window's corner to resize it.
Iconify - if you click on the _ near the top right hand corner of the folder window, it will tumble down into the task-bar at the bottom of the screen. The window can be restored by clicking on its name in the task-bar
Full Screen - to fill the screen with the window, click on the box near the top right hand corner of the directory window.
Kill - clicking on the x box kills the window. Using this risks losing your unsaved work. Try to use the program's Exit option instead.
The Screens Panel - The Screens box at the bottom-right shows 9 'virtual desktops'. All your windows so far have appeared on one virtual desktop (top-left), but by clicking on another virtual desktop you can start with an uncluttered screen. This facility helps keep your workspace tidy. You can move windows from one virtual desktop to another by dragging the mini-window using the middle button.

Note that you might have to click on a window before the text that you type goes into it.

The Emacs Editor

Starting the Editor

Create a file called pomodoro in your home directory. Now let's put something in the file. Double-click with the left mouse button on the pomodoro icon. When offered emacs, accept it. In Emacs you will see the majority of the screen is used to display the file you are editing. Below this is a bar with something like

--:--   pomodoro      (Fundamental)--L1--ALL-------

Beneath this there is a single line (the mini-buffer) for messages and editor commands. Along the top of the window is a menu-bar and icons.

Type in several lines of text (pressing the Return key at the end of each line). The arrow keys, and Delete key will work though the NumPad keys won't work until you press the Num Lock key.

There is an online tutorial for advanced emacs users which is started from emacs' Help menu. It is not recommended that you do this now. Further details can be found in the Unix from the Command Line handout.

Emacs Menus and Scrollbars

Across the top of the emacs window is a series of menus. The File menu contains items that let you load and save files. Select the Open File... option. A prompt will appear at the bottom of the window. If you were to type the name of a file here you would be able to edit that file. We won't do this just now so go to the Minibuf menu and select Quit to cancel the operation.

Go back to the File menu and select the Save Buffer item. This saves the file you are editing to disk. You must save files to disk before you try to perform any operations on them outside the editor.

We'll try searching the text now. Place the text cursor at the top of the text in pomodoro and pull down the Edit menu so that you can select the Search item in the Search sub-menu. A prompt will appear. Type in a string you can see at some point in the file and press the Return key. The editor will find the string and place the text cursor at the end of it.

Make sure pomodoro is at least five lines long and pull down the Edit menu. From the Go To sub-menu pick the Goto Line item. When the prompt appears specify 5 and press the Return key. The cursor should move to the fifth line of the file. Note that the line number is shown in the status line near the bottom of the window -- L5.

To copy some text, drag the mouse cursor over it using the left mouse button. Then click with the middle mouse button where you want the text to be copied. This facility also works between most kinds of text windows.

To delete a block of text, click once with the left mouse button at one end, and twice with the right mouse button at the other (or choose the Cut item in the Edit menu). If you want to move the text elsewhere, just click on the location with the middle mouse button.

If you want to move quickly around a document that is too big to fit on one page, you can use the scrollbar on the left of the window or the Page Up and Page Down on the keyboard by the arrow keys.

If you made an editing mistake you can use the Undo option in the Edit menu repeatedly until you get back to the way you were.

The Exit Emacs item in the Files menu makes the editor offer to save any files you have changed during the current editing session, and then kills the editor program. A backup copy of each file you change is kept by the editor. These are the files with names ending in the character `~'. Don't worry if you cannot always see them in your directory window, you will only need to use them if things go badly wrong.

Many of these actions can be performed using the icons under the menu-bar. Experiment to find out what they do.

Applications and logging off

If you click on

at the bottom-left of the screen you can explore what programs we have. In particular there's

Mozilla-Firefox - a web browser. You can use it for webmail too. You will need to become familiar with the WWW.
Help - a short-cut to CUED's help-on-the-web and list of Frequently Asked Questions. We expect you to become familiar with the help system
Printout Release - after printing a file it won't come out until you "release" it using this option.
Programs/CUED/Fast Feedback - our Fast Feedback Facility. Your chance to offer instant, anonymous feedback on teaching, computing, etc.
Programs/CUED/Survey - our under-graduate user survey.
XTerminal - provides a terminal window on the screen. This can be used to execute Unix shell commands. These are covered in the Unix from the command line document.

Logging off

To Log Out, use the Log Out item in the startmenu.

| computing help |