In about 15 minutes you will build a small project folder on the desktop using only typed commands: make folders, create a data file, write a Python program, run it, and save the result. No terminal experience is needed.

What you will build

By the end, this folder is on your desktop, and you made all of it by typing.

my_first_project
├── code      average.py
├── data      houses.csv
└── results   report.txt

Three rules before you start

Nothing happens until you press Enter.
Spelling and capital letters matter. Desktop works; desktop does not.
No message usually means it worked.

Windows: use Git Bash (free: install “Git for Windows” from git-scm.com, then open Git Bash), not PowerShell. If python3 is not found, type python instead.

Parts 1 to 4: build it and run it

Open the Terminal. Type each line exactly, and press Enter after each one.

Part 1: Build the folders

cd ~/Desktop
mkdir my_first_project
cd my_first_project
mkdir code data results
ls

You should see code data results. Look at the real desktop: the folder is there.

Part 2: Create a data file

echo "size,price" > data/houses.csv
echo "50,92" >> data/houses.csv
echo "80,142" >> data/houses.csv
echo "120,202" >> data/houses.csv
cat data/houses.csv

> creates the file, >> adds a line to it, and cat shows what is inside.

Part 3: Write a program

nano code/average.py

An editor opens. Type this, then press Ctrl+O and Enter to save, and Ctrl+X to exit.

total = 0
count = 0
for line in open("data/houses.csv").readlines()[1:]:
    size, price = line.strip().split(",")
    total += float(price)
    count += 1
print("Houses:", count)
print("Average price:", round(total / count, 1))

Part 4: Run it

python3 code/average.py

You should see:

Houses: 3
Average price: 145.3

Parts 5 to 7: save, tidy, check

Part 5: Save the result to a file

python3 code/average.py > results/report.txt
cat results/report.txt

The > sends the program's output into a file instead of the screen.

Part 6: Copy, rename, delete

cp results/report.txt results/report_backup.txt
mv results/report_backup.txt results/old_report.txt
ls results
rm results/old_report.txt

cp copies, mv renames or moves, and rm deletes. There is no recycle bin, so check the name before you press Enter.

Part 7: Check the finished project

ls -R
pwd

ls -R lists every folder and file inside. pwd should end in Desktop/my_first_project.

Extra challenges

For when you finish early.

Add a fourth house (160,292) to the data file and run the program again. Does the average change?
Change the program so it also prints the most expensive house.
Make a folder called notes and write a file in it listing the commands you learned today.

If something goes wrong

What you see	What it means	What to do
`command not found`	A typing mistake in the command	Press the up arrow, fix it, press Enter
`No such file or directory`	Wrong name, or you are in the wrong folder	Type `cd ~/Desktop/my_first_project`, then `ls` to see what is there
The Terminal seems frozen	A program is still running	Press `Ctrl`+`C`
Nothing shows when you type a password	Normal: the Terminal hides passwords	Type it and press Enter
A long name is hard to type		Type the first letters and press `Tab`

Welcome to CMPS 530