4,222 Introduction to Programming
Lecture 2: Summary
Dr. Aurélien Sallin
2026-02-27
The Terminal
- A text-based interface to interact with your computer
- Mac uses bash (Terminal), Windows uses Command Prompt or PowerShell. In this course, we focus on bash and command prompt commands.
- All commands operate relative to your current working directory. Always know where you are!
- Paths: absolute (
C:/Users/Bilbo/Documents/) vs relative (../Documents/)
The Terminal
| Action | bash (Mac) | Command Prompt (Windows) |
|---|---|---|
| Show current directory |
pwd
|
cd (without arguments)
|
| List files |
ls
|
dir
|
| Navigate |
cd <path>
|
cd <path>
|
| Create directory |
mkdir
|
mkdir
|
| Write text to file |
echo “text” > file
|
echo text > file
|
| Home shortcut |
~ (e.g. cd ~/Documents)
|
- |
| Current directory shortcut |
.
|
.
|
| Parent directory shortcut |
..
|
..
|
Using Visual Code
The IDE
- VS Code is our IDE: code editor + terminal + extensions in one tool
- Always open VS Code from your project directory (
code .) - Install extensions: Python, Pylance, Ruff, Jupyter
Python & Environments
Why Python?
- Readable, versatile, widely used in data science, economics, and AI
- Coming from R: watch out for 0-based indexing and indentation
Python & Environments
Virtual Environments with uv
- Each project gets its own isolated environment (its own “kitchen”)
- Never install packages globally, always use environments!
- Key commands:
uv init –python 3.14.1
|
Create a new project |
uv add pandas numpy
|
Add packages |
uv run main.py
|
Run a script in the environment |
uv sync
|
Install dependencies from lock file |
- Key files:
.python-version,pyproject.toml,uv.lock,.venv/