CP367: Lab 01 - Winter 2026

This lab introduces the mechanics and practices of the CP367 labs. We assume that you have a basic grounding in using email and a web browser . If you need extra help for anything related to a lab, please talk to the Lab Instructor.

Administration

In order to work effectively in this course, you must have the following:

a Laurier email address
access to the CP367 web site (which you are looking at now)
subscription to the course mailing list
access to MyLearningSpace
an account on the department's unix server hopper

Most of these things are automatically made available to you - just make sure they are all working. If you have problems with any of them, please let your lab supervisor know as soon as possible.

Talking to `hopper`

Most of your work in this course will be done using a unix command line environment, or console. Although this may seem primitive, command line environments are still in wide use, particularly 'under the hood' of unix and linux boxes where GUI interfaces are either not sufficient or non-existent for certain types of work.

You will be working on the department's unix server hopper , named after Rear Admiral Grace Hopper, a pioneer in the computer science field. hopper is running Oracle Linux 7.

The PCs in labs N2085 and N2095 provide the SSH client software putty. putty is small, full-features, robust, and best of all, free. You are welcome to use any SSH client you like, but we will demonstrate the use of putty in this lab and throughout the course.

Note that for security reasons ICT allows access to putty only from on-campus.

Starting putty from the Windows desktop brings up the following dialog window:

For the Host Name enter hopper.wlu.ca , and make sure the SSH connection type is selected. hopper rejects non-SSH connections. Then press the Open button.

putty 's default settings should work fine for your SSH connections, but you are welcome to change the window size, font, virtual terminal type, etc. You cannot save putty session settings to a lab PC, but you certainly may on your own computer.

Your `hopper` unix Account

putty opens a simple console window that gives you command line access to your account on hopper . The course lab supervisor created all course accounts before the first lab - you may have a hopper account from a previous course. The account uses your Laurier login based upon your surname and student ID number.

When logging inthe putty console window looks something like this:

You are first asked for your login, then for your password. Your password is not displayed as you type it. Press the enter key when you have finished typing your password. hopper then gives you the system command-line prompt. (Note: when logging into hopper you may not be asked for your password as it is picked up from the machine you are running putty on. This is not a problem.)

You may be asked to accept an SSH key - answer 'Yes'.

The system command-line prompt (hereafter 'prompt') tells you where in the hopper file system you are currently located. In the example above, the user dbrown has an account in the /home/dbrown folder. As you move through the file system the prompt changes to match your current location. For most intents and purposes you have legal access to your folder in /home and any subfolders you may create only. You have read access to numerous other folders on the system, mostly for access to software. This will be discussed in greater detail in later labs.

To log out of your account and automatically close the SSH client window, type exit , followed by the Enter key.

The default hopper shell is bash . If you wish to change to another shell you are welcome to do so, but all examples are done in bash . (If you have no idea what this means, then leave it alone.)

By default you have a public_html folder in your account that you may use to post web pages. Your URL is http://hopper.wlu.ca/~your_account/ . (The sample URL is http://hopper.wlu.ca/~dbrown/)The public_html folder contains a default index.htm file that you are free to edit. Just remember the 50MB quota on your account!

putty allows you to copy and paste from its terminal window. To copy, use your mouse to highlight the text you wish to copy - it is automatically copied to the PC's clipboard. To paste into the terminal window right-click anywhere in the window with the mouse cursor and the clipboard text will be pasted at the current location of the text cursor (not the mouse cursor).

Editing

You will be editing, compiling, and executing C programs and shell scripts on hopper . There are a number of editors available on hopper , but by far the most powerful is emacs .

To start emacs simply type emacs at the prompt:

Welcome to Emacs

File Edit Options Buffers Tools Help                                            
Welcome to GNU Emacs

Get help           C-h  (Hold down CTRL and press h)
Undo changes       C-x u       Exit Emacs               C-x C-c
Get a tutorial     C-h t       Use Info to read docs    C-h i
Ordering manuals   C-h RET
Activate menubar   F10  or  ESC `  or   M-`
(`C-' means use the CTRL key.  `M-' means use the Meta (or Alt) key.
If you have no Meta key, you may instead type ESC followed by the character.)

If an Emacs session crashed recently, type M-x recover-session RET
to recover the files you were editing.

GNU Emacs 21.3.1 (i386-pc-solaris2.10, X toolkit, Xaw3d scroll bars)
 of 2008-08-10 on einstein
Copyright (C) 2001 Free Software Foundation, Inc.

GNU Emacs comes with ABSOLUTELY NO WARRANTY; type C-h C-w for full details.
Emacs is Free Software--Free as in Freedom--so you can redistribute copies
of Emacs and modify it; type C-h C-c to see the conditions.
Type C-h C-d for information on getting the latest version.
----:---F1  *scratch*         (Lisp Interaction)--L1--All-----------------------
For information about the GNU Project and its goals, type C-h C-p.

Before we can create a C program we need to create a directory to put it in. To create a CP367 directory in your account, type the following commands at the prompt:


mkdir CP367
cd CP367

The first command creates a new directory ( mkdir - Make Directory) in your account named CP367 . The second command moves your 'focus' to that directory ( cd - Change Directory). You should see that your prompt now shows CP367 as part of it to indicate that you are in the CP367 directory.

Now you can create program files in the CP367 directory. To start emacs with a file (your normal approach), type emacs filename at the prompt, as in this example:

emacs ctest.c

which allows you to enter:

Editing in Emacs

File Edit Options Buffers Tools C Help                                          
/*
 * ctest.c
 *
 *  Created on: 2024-01-03
 *      Author: David Brown
 */
#include <stdio.h>

int main() {
    char letter;
    for (letter = 'A'; letter <= 'z'; letter++) {
        printf("%c\n", letter);
    }
    return 0;
}






----:---F1  ctest.c           (C Abbrev)--L1--All-------------------------------
Loading cc-mode...done

emacs is designed to work with dozens of terminal types, and they all have their own quirks and specific types of interface. We will concern ourselves only with the keys and commends that work with hopper and putty in our labs. Should you connect to hopper from another type of terminal be aware that some of the key associations mentioned here may not work with those types - you are responsible for finding alternatives.

The three most important keys in emacs are:

The CTRL key, denoted as C- . Hold down the actual keyboard Ctrl key in combination with whatever other key is noted. Example: to exit emacs , press C-x C-c
The META key, denoted as M- . Press and release the actual keyboard Esc key followed by the next required key. Example: to move to the next word, press M-f

The MENU key, to activate the emacs menu bar. Press the F10 function key to bring up the menu, as in this example:

Emacs Menu

File Edit Options Buffers Tools Minibuf Help                                    
/*
 * ctest.c
 *
 *  Created on: 2024-01-03
 *      Author: David Brown
 */
#include <stdio.h>

int main() {
----:---F1  ctest.c           (C Abbrev)--L1--Top-------------------------------
Press PageUp Key to reach this buffer from the minibuffer.
Alternatively, you can use Up/Down keys (or your History keys) to change
the item in the minibuffer, and press RET when you are done, or press the
marked letters to pick up your choice.  Type C-g or ESC ESC ESC to cancel.
In this buffer, type RET to select the completion near point.

Possible completions are:
f==>File                           e==>Edit
o==>Options                        b==>Buffers
t==>Tools                          c==>C
h==>Help
----:%*-F1  *Completions*      (Completion List)--L1--All-----------------------
Menu bar (up/down to change, PgUp to menu): f==>File

Keys may be combined. Thus, M-C-p means press Esc followed by Ctrl-p .

The cursor control (arrow) keys work as you would expect, and the Backspace key deletes characters to its left. The Delete key does nothing (which can be a problem).

Tasks

We will briefly use emacs to create the following file. Enter this C code into the file ctest.c :

ctest.c

					
/*
 * ctest.c
 *
 *  Created on: 2024-01-03
 */
#include <stdio.h>

int main() {
    char letter;
    for (letter = 'A'; letter <= 'z'; letter++) {
        printf("%c\n", letter);
    }
    return 0;
}

Exit emacs , and at the prompt compile this file using the gcc compiler by entering the following command at the prompt:

gcc -g -o ctest ctest.c

If it compiles without error, run the file by typing the following command at the prompt:

./ctest

CP367: Lab 01 - Winter 2026 - Introduction

Due 11:59 PM, Friday, January 16, 2026

Administration

Talking to `hopper`

Your `hopper` unix Account

Editing

Tasks

CP367: Lab 01 - Winter 2026 - Introduction

Due 11:59 PM, Friday, January 16, 2026

Administration

Talking to hopper

Your hopper unix Account

Editing

Tasks

Talking to `hopper`

Your `hopper` unix Account