Software for CSE 341

Compilers or interpreters for all of the languages we'll be using this quarter should be installed on the undergrad computers on both Windows and Linux. You can also download and install them on your own machine if you have one. Specific directions for each language will be in the materials for that language.

Using Linux and Emacs in CSE 341

Working in the CSE Labs

If you're going to use the lab machines, everything is set up for you. If there is an application, simply search for it locally (e.g. DrRacket, Emacs, etc). Otherwise, you will be able to compile/run the necessary languages via terminal/command line. If you need a refresher on terminal commands, see the "Basic Unix Commands" section.

The department also has a cluster of four linux servers for instructional use known as attu. You can ssh to attu.cs.washington.edu and be connected to one of the four servers.

• To access attu from a Windows machine in the lab, go to Unix Connectivity / ssh attu in the menu, and log in via the terminal. This will set up the display correctly on your local windows machine. (For example, if you run emacs on attu, it will pop up in a separate window on your windows machine.)
• There is probably less reason to access attu from a linux machine in the lab, since you're already on linux. But if you want to, open an xterm, and give the command ssh attu. This alone won't set up the display variables, so just run things that interact in the terminal window.

Working elsewhere

1. Installing a particular piece of software is listed under a particular language (e.g. "Running Racket"). Generally you should get the latest stable release, although other recent versions should be OK as well.
2. If you want to run something on a department linux machine, use a terminal and ssh to run Haskell, Prolog, Ruby, and Java. We recommend using emacs as your editor for this option. (This won't work with Racket though.)To ssh, follow the following instructions based on your machine:
   • Mac/Linux:
     1. Open a terminal window, and run the following command, substituting your username for USERNAME:

         ssh USERNAME@attu.cs.washington.edu

     2. Enter your password, and you should be logged in!
   • Windows
     • There's no default terminal that'll allow ssh'ing, so you'll have to download a package to do it for you. Here is a popular option:
       • Putty: https://www.chiark.greenend.org.uk/~sgtatham/putty/
         1. Within the "Session" tab, paste everything after 'ssh' (from the Mac/Linux instructions) in the "Host Name" field and click "Open".
         2. Enter your password, and you should be logged in!

Note that this will not allow you to launch GUIs (e.g. DrRacket) and have it displayed on your computer. However, for the software for this course, it will be sufficient to install GUI applications on your own machine, or use the lab machines and just interact via the terminal window.

Basic Unix commands

attu4% mkdir mydir
attu4% ls
mail  mydir
attu4% cd mydir
attu4% pwd
/homes/iws/sbfan/mydir
attu4% exit

• To make a directory, and name it, say "mydir", you would type "mkdir mydir".
• "ls" lists what you have in your current directory.
• "cd" will change directories. To change to a directory "mydir", for example, type "cd mydir". To move back out of a directory, type "cd ..", and to get back to your home directory, "cd ~".
• To check where you are, type "pwd".
• "exit" exits.
• To get help on some command, say you want to know how to use "ls", type "man ls" and you will get the manual pages for that command. (Alternatively, you can use "info" in the same way.)

Accessing your UNIX home directories from Windows lab machines

If you're in the basement labs, your Z: drive should already be mapped to your Unix home directory. Look under for the Z: drive under "My Computer" in the Start Menu. All the files you saved while working on Attu should be there.

Emacs

• The cursor is a rectangular block and is referred to as the point.
• The modeline displays information about the buffer displayed in the current window. A buffer is a logical "thing" that you are working on. When you open a file, it will be loaded into a buffer, typically with the same name as the file.
• Every buffer is edited in a mode. The most basic mode is Fundamental, which provides only the most basic Emacs editing features. There are modes for many different languages.
• There are many "special" buffers that do not correspond to loaded files. The one above is called *scratch*. This buffer runs in Lisp Interaction mode, which means that you can interactively type and evaluate expressions in the Lisp programming language.

Emacs uses many key combinations involving the Control and Meta keys. Such key combinations are denoted C-x (Control-x (lowercase)) or M-x (Meta-x). On keyboards that don't have Meta, Alt is usually an acceptable substitute. If Alt doesn't work, ESC-x is equivalent to M-x.

A sequence of key presses is written like C-a C-b M-x, which would mean do the three actions in sequence.

• C-x C-c: Quits Emacs.
• C-g: Cancels the current action.
• C-x C-f: Opens a file.
• C-x C-s: Saves a file.
• C-x C-w: "Save as" (save contents to file with a name you type).

• C-x 2: Split the window into 2 buffers, one above the other. (Use the mouse or C-x o to switch between them.
• C-x 0: Undo window-splitting so there is only 1 buffer.
• C-x b: Switch to another buffer by entering its name.
• C-x C-b: See a list of all current buffers.

• C-h: Help. Hitting this will display a short message in the minibuffer: C-h (Type ? for further options).
• C-h t: Built-in interactive tutorial. Some people don't like this tutorial, but some people find it helpful.
• C-h b: Key bindings. This lists all key bindings that are valid for the current mode. Note that key bindings change from mode to mode!
• C-h a: Command apropos. After hitting C-h a you can type a symbol and a window will appear that lists all symbols and functions that match that phrase.