Course Info / Syllabus

Labs

Lecture Topics

Exam Reviews

Source Code & Other Resources

Operating Systems Concepts & Design

Lab 02 - Permissions

Lab Procedure

Beginning with this lab, you will be accessing an AWS instance - a virtual system hosted on the cloud - to access a Ubuntu server environment.

Go to your cloned repository folder (likely named ceg2350s25-yourgithubusername).

Create a new directory, Lab02

Create a file named README.md in the Lab02 folder. Copy into the file the contents of the Lab 02 Template.

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.

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 0 - editor in training

For this course, you will be creating and editing files in Linux. Therefore, you will need to get acquainted with at least one command line text editor. vim will be the editor used in course demonstrations.

vim

nano

Part 1 - AWS Academy Setup

An email was sent to your wright.edu account inviting you to join an AWS Academy Course for this class.

Follow the instructions in AWS Academy to set up your AWS environment and make your first ssh connection to your AWS instance.

The written instructions are thorough, but if you would like more visuals visit the Pilot -> Content -> Labs -> Getting Started for a video companion guide to creating an instance. The video guide sets up connections with WSL2 specifically, but PowerShell or other Terminals will have similar themes - know where you put your file, the name of it, and the system path to it.

Wherever your lab instructions state that the exercise must be completed in your instance, it must be completed in your instance.

If you break your ability to connect to your instance, you can rebuild by repeating the instructions in AWS Academy Setup.

You will note your command to SSH to your instance in the Lab Template.

The remainder of this lab is to be completed by using your AWS instance.

Part 2 - Bits of permissions

For each command below, write a verbose description of what it does.

Sample:

  1. chmod u+r bubbles.txt
  2. chmod u=rw,g-w,o-x banana.cabana
  3. chmod a=w snow.md
  4. chmod 751 program
  5. chmod -R ug+w share

Resources

Part 3 - Regular bob

For these exercises, replace bob with a username based on your first initial followed by last name. For example, “John Smith” would be jsmith

Perform the following exercise on your AWS instance.

  1. Create a new user named bob (replace with your username, see above)
  2. What is the path to bob’s home directory?
  3. Can ubuntu add files to bob’s home directory? Why or why not?
    • For credit, answer must include what was to to justify answer.
  4. Switch to the user bob
  5. Get to bob’s home directory
  6. Can bob add files to bob’s home directory? Why or why not?
    • For credit, answer must include what was to to justify answer.
  7. Switch back to the ubuntu user
    • Note that the ubuntu user does not have an account password. You’ll have to find a more administrative way to switch accounts…
  8. Return to the ubuntu user’s home directory

Part 4 - Get a crew

Perform the following exercise on your AWS instance.

Create a folder named share in the ubuntu user’s home directory and create some files in the folder to play with.

Reminder to replace references to bob with your username of first initial, last name (ex. jsmith)

  1. Create a new group named crew
  2. Add ubuntu and bob to the crew group (replace with your username, see note)
  3. Change share in the ubuntu user’s home directory so that crew is the group for the whole folder and members of crew can make changes in the folder.
    • Yes, including contents in share
  4. Switch user to bob
  5. As bob create a file in share.
  6. Why was this successful?

User & Group Resources

Part 5 - sudo make me a sandwich

Perform the following exercise on your AWS instance.

  1. In the ubuntu user’s home directory, make a file with sudo named sudowho.txt
  2. What are the permissions and ownership of this file?
    • Rephrased, who (which categories) can do what?
  3. Without modifying the permissions or ownership of the file, edit the file and add some text, and save the changes.
  4. Modify the permissions and ownership to make ubuntu the owner and crew the group associated with the file.

Resources

Submission

Rubric