Lab 03 - git, IO, and scripts

• Lab Procedure
• Part 1 - git going
• Part 2 - clone
• Part 3 - IO Redirection
• Part 4 - Rolling the Dice
• Part 5 - Retrospective
• Extra Credit - Room for Improvement
• Submission
• Rubric

Lab Procedure

Make sure to return to the AWS Learner Lab page (link in Pilot if you forgot to bookmark it) and hit “Start Lab” to turn on your sandbox / AWS instance

Use ssh to connect to your AWS Ubuntu instance.

PAUSE AND READ THIS Starting with this lab, you will clone your GitHub repository for your coursework to your AWS instance in addition to having it cloned to your personal system. I would pick from one of two methods since you will now be able to access your repository from two different systems.

Method 1: Only work in the cloned folder on your AWS instance and use git commands to add your changes to commits, make commits, and push changes. If you open the folder on your system (not the instance), you’ll need to pull to synchronize.

Method 2: Create the file for your answers on your system (not the AWS instance), and work on the script on the instance (in your repository folder). As you make changes in the repository folder on one system you will need to remember to make commits, push the changes - and then pull those committed changes on the other system to get the folder up to date.

If a push / synchronize seems to fail / is blocked, you likely need to pull

OKAY, GO!

Create a new directory, Lab03

Create a file named README.md in the Lab03 folder. The Lab 03 Template can be copied from this link:

• https://raw.githubusercontent.com/pattonsgirl/CEG2350/refs/heads/main/docs/Labs/Lab03/LabTemplate.md

You may refer to additional resources outside of the recommended resources provided.

Any resource that you use that contributes to your understanding of exercises in this lab should be cited in the Citations section of your lab answers. To add citations, provide the site and a summary of what it assisted you with. If generative AI was used, include which generative AI system was used and what prompt(s) you fed it.

Generative AI may not write your script for you, only assist with component and how-to type questions.

If you make mistakes with commands in the lab, note them! Writing down what went wrong and what the correction was will significantly help your learning journey. If you cannot find a correction, it will help the TAs or myself understand what point you reached and determine some potential solutions.

Part 1 - git Guide

In your lab template, fill out the Description column with what the corresponding git command does. You’ll be using these commands all semester long to interact with your GitHub repository from your AWS instance.

git command	Description
git clone repo_URI
git status
git add filename
git commit
git push
git pull

Resources

• freeCodeCamp - Learn the Basics of Git in Under 10 Minutes
  • this is a useful read to understand the context of what the above commands do.

Part 2 - clone

ssh to your AWS instance for this part. It is highly recommended you look at the Resources listed below.

• Useful commands for this part: ssh-keygen, cat, git clone

1. Create an SSH key pair on your AWS Ubuntu instance.
2. Add the public key to GitHub
3. To clone your student repository for this course, go to your repository page in a browser: https://github.com/WSU-kduncan/ceg2350s25-YOURGITHUBUSERNAME
   • Select the Code dropdown. Make sure SSH is selected.

• Resources:
• GitHub - How to Use - Duncan’s Guide
• Warp - Set up SSH for Git
  • Remember I don’t recommend setting up a passkey because you have to do additional setup
• GitHub - Generating a New SSH Key
• GitHub - Adding SSH key to your GitHub Account

Part 3 - IO Redirection

Find out what each command (including its flags) does and write a description beside it. Don’t forget to lookup commands & flags using man and / or some Google-fu (ability to use Google search) to find out. All of the commands can be run - a note is included if there is any additional setup to make it work.

Sample:

• echo "This is easy" > button
• Full credit: echo prints “This is easy” to standard output, which is redirected to the file named button in the current directory. button now contains the text, “This is easy”.

1. printenv HOME > thishouse
2. cat doesnotexist 2>> hush.txt
3. cat nums.txt | sort -n >> all_nums.txt
   • To run: create a file named nums.txt containing random numbers, each on a new line
4. cat << "DONE" > here.txt
5. ls -lt ~ | head
6. history | grep ".md"

Resources:

• An Intro to Linux IO Redirection
• RedHat - How to manipulate files with shell redirection and pipelines in Linux
• freeCodeCamp - How to Set an Environment Variable in Linux
• Linuxize - How to Set and List Environment Variables in Linux

Part 4 - Rolling the Dice

Use your AWS instance for this part. Create the script file in your GitHub repository.

The overall goal is to create a script that randomly generates a set of random numbers within the range specified by the script user. In steps 1 - 5, assume you are rolling one die.

To complete the overall task, perform the steps listed below. After each step is complete and tested, create a commit with your changes. push commits as you wish, just remember the push saves all the commits to the mighty GitHub cloud. Your commit message must include which task you completed.

If you don’t make it through all of a step or don’t complete all 6 steps, leave heavy comments for partial credit considerations.

Generative AI may not write your script for you, only assist with component and how-to type questions.

1. Create a bash script named roll. Output a random number between 1 and 20.
   • Script should run when ./roll OR bash roll is typed on command line. Think about permissions.
   • Output should say: You rolled a ##, where ## is the randomly generated number.

2. Change script to prompt the user for a number. If the number is less than 1, output an error message. Output a random number between 1 and the user’s number.

3. Change script to take an argument from the command line instead of prompting the user. If no argument is passed, output an error message. Output a random number between 1 and the argument passed.
   • Script should run when ./roll ## is typed on command line, where ## is a number

4. Change script to also check if the given argument is greater than 1. If no argument was given, prompt user for a number, and check that it was greater than 1. Output a random number between 1 and the number.

5. Change the script to prompt the user for a valid number if the argument was not provided or was not greater than 1. Prompting continues until a number greater than 1 is given. Output a random number between 1 and the valid number.

6. Change script to take two arguments from the command line. The first argument will indicate number of dice to roll. The second will indicate how many sides of the dice. If there are less than or more than two arguments, or if the arguments are not greater than one, prompt the user for valid values for number of dice and number of side. Output a random number between 1 and the number of sides for each die.
   • Script should run when ./roll ## ## is typed on command line.
   • Output should say: Die 1 rolled a ## Die 2 rolled a ##, where ## are two randomly generated numbers, one for each die.

Resources:

• IO Flood: Bash Shell Scripting: Random Number Generation
• IO Flood: Bash read man page: Using the Linux read command
• Digital Ocean - How to Read Command Line Arguments in Shell Scripts?
• Cloudzy - Bash If Statement: Syntax, Variations, Use Cases, Commands, and More!
• IO Flood - Bash While Loop: Shell Scripting Reference Guide
• ShellCheck - finds bugs in your shell scripts

Part 5 - Retrospective

A retrospective is a moment of refection after a task.

1. Where and when did it go wrong while working on your script tasks?
2. Was anything familiar working with a new language compared to one you are used to?
3. Assuming you pushed your commits to GitHub, view your commit history. Did you write good commit messages that refer to what tasks were completed at each commit? What would you improve?

Extra Credit - Room for Improvement

Make a notable improvement to the roll script. This could be another feature, an additional boundary check on allowed conditions, experimenting with colored text for standard and error output… If you have an idea, you are encouraged to run it by the TAs first to make sure it is worthy.

Make sure you commit and push your script changes for grading and add a note of what you did in the answer template.

Submission

• In the Pilot Dropbox, paste the URL to the Lab03 folder in your GitHub repo
  • URL should look like: https://github.com/WSU-kduncan/ceg2350-YOURGITHUBUSERNAME/tree/main/Lab03
• Your Lab03 folder should contain (at minimum):
  • README.md
  • roll

Rubric

• Part 1 - 6 pts
• Part 2 - 4 pts
• Part 3 - 6 pts
• Part 4 - 6 pts
  • minimum of 6 commits, each commit completes 1 task
  • 1 complete task = 1 pt
• Part 5 - 3 pts
• Extra Credit - 1 pt
• Point deductions:
  • minus 2 pts = no commits for each part in roll script && no commit messages indicating parts building on each other
  • minus 1 pt = commits / comments indicate parts building on each other, but not all commits were broken out as asked