Key Word(s): tmate, docker, podman, vim, emacs, nano

Pair Programming Exercises¶

Week 1 (September 2nd - September 7th)

Exercise 1¶

The purpose of this exercise is to help you ease into the course flow for the semester. You will learn where to find the homework assignments and how to correctly set up your git repo for this course.

Tasks¶

Do problem #2 on Homework 1 https://harvard-iacs.github.io/2021-CS107/category/homework.html

Exercise 2¶

By the end of this exercise, you will be ready to use tmate for pair programming.

Tasks¶

Create a new directory called pair_programming/PP1 in your personal git repository
Install tmate (https://tmate.io/) on your system. If you use Ubuntu, you could accomplish this with
```
sudo apt-get install tmate
```
Alternatively, you could install docker and use
```
docker pull cs107sysdev/ubuntu
```
to pull the Ubuntu image we have prepared for you. For installing docker see these references:
- Mac: https://docs.docker.com/desktop/mac/install/
- Windows: https://docs.docker.com/desktop/windows/install/ (requires WSL 2, see System Requirements)
- Linux: Use your repository package manager. E.g. for Ubuntu https://phoenixnap.com/kb/install-docker-on-ubuntu-20-04. Alternatively, you can install podman which is a rootless alternative to docker (https://podman.io/) The additional benefit of using a docker image is that the working environment that you share with your pair-programming mates is isolated from your personal system. You can run the docker image by using
  this helper script.
  You can copy this script into your ~/bin directory and then run the following (assuming you are inside your personal GitHub repository and run_cs107_docker.sh is in your $PATH variable):
```
run_cs107_docker.sh pair_programming/PP1
```
If the run_cs107_docker.sh is not in your $PATH or the above fails, you can just copy the script in your current directory and run:
```
bash run_cs107_docker.sh pair_programming/PP1
```
This will launch the Ubuntu container and drop you inside your PP1 directory. You can then simply launch tmate and share the session with your mates. They will only have access to the container but not your personal computer.

Exercise 3¶

All work on PP exercises should be committed to your master or main branch. If you have begun to work on HW1, please switch to the HW1-dev branch and commit that work on this branch before checking out master or main and continuing with this exercise. Feel free to ask your TF if you have any issues. The 'Example Homework Workflow' section on the course flow page provides the details as well.

You will be assigned a random group and sent to a breakout room. Please wait for your TF. This exercise will be performed in the PP1 directory that you just created.

By the end of this exercise, you will have gone through your first pair programming workflow! We will check that you successfully pushed the README.md file to your repo.

Tasks¶

Start a tmate session inside your PP1 directory (either directly or via docker) and invite your PP team members by sharing the link to your session, either ssh or the web link (you can share the read-only link for this session).
Create a README.md file. Choose an editor of your choice, examples are:
- nano (easy)
- pico (easy)
- vim (advanced but recommended)
- neovim (behaves the same as vim but code has been rewritten from scratch)
- emacs (advanced)
- ne (easy, comes with a TUI, https://ne.di.unimi.it/)
- tilde (easy, also with a TUI, https://os.ghalkes.nl/tilde/) All these editors are available in the cs107sysdev docker image. You can put anything you want inside your README.md file. A good choice would be something like the example below.
```
# Pair-Programming Week 1

Hello [`tmate`](https://tmate.io/)
```
You may do this one after the others, while your team mates watch what you are doing in their read-only session.
Inside the terminal, from the command line, play around with some of the Linux commands you started to learn in lecture. At the very least, try to use ls and some of its options.
Now commit the README.md file you have just created on your master or main branch. It should be on this path pair_programming/PP1/README.md. When you are done, you can push your contribution with git push and verify that everything is fine by checking on your GitHub account.

A few comments¶

The tasks above are not necessarily connected. The main goal is to help you get familiar with the correct workflow.
For example, you can choose to share your code with your partners or not for this session. In the future, you will be required to share code.
You can open the editor by passing a filename as an argument. For example, nano README.md would open nano with an empty README.md file. You can then edit the file to your liking and save the contents by pressing Ctrl-O and hitting Enter to confirm that you want to save. You can then exit nano by pressing Ctrl-X.
vim is a modal editor which means you can not start typing text right away. If you want to play with vim, these are the steps:
1. Open a new file: vim README.md
2. Press i, this will enter INSERT mode
3. You can now enter text as you like
4. To exit INSERT mode and enter NORMAL mode, press the ESC key
5. To save your work and exit vim at the same time, press :wq followed by Enter. This will write (w) and then quit (q).