# WSL / Ubuntu Command-Line Cheat Sheet

## Filesystem Navigation

| Command | What it does | Example |
|---------|-------------|---------|
| pwd | Print the current directory (where you are) | pwd → /home/alice |
| ls | List files and folders | ls, ls -la (detailed view) |
| cd <dir> | Change directory | cd Documents, cd ~ (home), cd .. (up one) |
| mkdir <name> | Create a new directory | mkdir projects |
| rmdir <dir> | Remove an **empty** directory | rmdir old_folder |

## File Operations

| Command | What it does | Example |
|---------|-------------|---------|
| touch <file> | Create an empty file | touch notes.txt |
| cp <src> <dst> | Copy a file | cp notes.txt backup.txt |
| mv <src> <dst> | Move or rename a file | mv notes.txt ~/Documents/ |
| rm <file> | Delete a file (⚠️ no trash bin) | rm temp.txt |
| rm -r <dir> | Delete a folder and **everything inside** | rm -r old_project/ |
| cat <file> | Print a file's contents to the terminal | cat notes.txt |
| less <file> | View a file page-by-page (press q to quit) | less long_file.txt |
| head <file> | Show the first 10 lines | head data.csv |
| tail <file> | Show the last 10 lines | tail -n 20 data.csv |
| nano <file> | Edit a file in the terminal | nano notes.txt |

## Viewing & Finding

| Command | What it does | Example |
|---------|-------------|---------|
| file <name> | Show what type of file something is | file notes.txt |
| find <dir> -name <pattern> | Find files by name | find ~ -name "*.md" |
| grep <pattern> <file> | Search inside files | grep "error" log.txt |

## Permissions

| Command | What it does | Example |
|---------|-------------|---------|
| chmod <mode> <file> | Change file permissions | chmod +x script.sh (make executable) |
| sudo <command> | Run a command as admin (root) | sudo apt update |

## Package Management (apt)

| Command | What it does | Example |
|---------|-------------|---------|
| sudo apt update | Refresh the list of available packages | Run before installing anything |
| sudo apt install <pkg> | Install a package | sudo apt install clang |
| sudo apt upgrade | Upgrade all installed packages | sudo apt upgrade |
| sudo apt remove <pkg> | Uninstall a package | sudo apt remove clang |
| apt search <keyword> | Search for a package | apt search image editor |

## Pipes & Redirection

| Command | What it does | Example |
|---------|-------------|---------|
| cmd1 \| cmd2 | Send output of cmd1 into cmd2 | ls \| grep ".txt" |
| > | Redirect output to a file (overwrite) | echo "hello" > hello.txt |
| >> | Redirect output to a file (append) | echo "world" >> hello.txt |

## WSL-Specific Tips

- Your **Windows files** are under `/mnt/c/` — e.g. `/mnt/c/Users/YourName/Documents`
- Your **Linux home** is at `/home/yourname` (type `~` as a shortcut)
- Drag a file from Windows Explorer into the terminal to paste its WSL path
- Use `explorer.exe .` to open the current Linux folder in Windows File Explorer

## Useful Shortcuts

| Shortcut | What it does |
|----------|-------------|
| Ctrl + C | Cancel the current command |
| Ctrl + D | Exit the terminal / close session |
| Tab | Auto-complete file and folder names |
| ↑ / ↓ | Scroll through command history |
| Ctrl + L | Clear the screen |

## Quick Reference — First Steps

```bash
# Where am I?
pwd

# What's in this folder?
ls -la

# Make a project folder and go inside
mkdir my_project
cd my_project

# Create a file and edit it
touch hello.txt
nano hello.txt

# Come back home
cd ~
```