# Rpi Basics
---
## 🐧 **Day 2: Linux & Terminal Basics on Raspberry Pi**
---
### 🎯 **Learning Objectives**
By the end of today, learners will:
* Navigate the Linux filesystem using the terminal.
* Use essential Linux commands for managing files and directories.
* Install and remove software using `apt`.
* Understand file permissions and user roles.
* Enable and use SSH & VNC to remotely access the Raspberry Pi.
---
`ssh pi1@raspberry1.local`
### 🧠 **Topics & Content**
---
### 🗂️ 1. **Linux Filesystem Structure**
Explain the hierarchy using a tree:
```javascript
/
├── bin # Essential binary programs
├── boot # Boot loader files
├── dev # Device files
├── etc # System configuration files
├── home # User home directories
│ └── pi # Home directory for user 'pi'
├── lib # System libraries
├── media # Mounted drives (USB, SD)
├── opt # Optional application software
├── tmp # Temporary files
├── usr # User programs and data
└── var # Variable data (e.g., logs)
```
> ✅ Tip: Your working directory is usually `/home/pi`
> Use `pwd` to check where you are.
---
### 💻 2. **Basic Linux Commands**
Practice the following:
| Command | Description |
| --- | --- |
| `pwd` | Print current directory |
| `ls` | List contents |
| `cd foldername` | Change directory |
| `cd ..` | Go to parent directory |
| `mkdir name` | Create new folder |
| `rm file` | Delete file |
| `rm -r folder` | Delete folder recursively |
| `nano file.txt` | Open file in editor |
| | |
| `top` | Show system processes |
| | |
**Practice Task:**
```bash
cd ~
mkdir day2
cd day2
nano hello.txt
```
---
### 📦 3. **Package Management with APT**
APT (Advanced Package Tool) is used for installing and managing software.
* Update package list:
```bash
sudo apt update
```
* Upgrade installed packages:
```bash
dsudo apt upgrade -y
```
* Install a package:
```bash
sudo apt install cowsay
cowsay "Linux is fun!"
```
* Remove a package:
```bash
sudo apt remove cowsay
```
> 🔍 Explore: Try installing `neofetch`, `htop`, or `python3-pip`
---
### 🔐 4. **File Permissions and Users**
Use `ls -l` to check permissions:
```bash
-rw-r--r-- 1 pi pi 1234 Jun 14 hello.txt
```
**Breakdown:**
* `rw-` → owner can read/write
* `r--` → group can read
* `r--` → others can read
**Change permissions:**
```bash
chmod 755 myscript.sh
```
**Change ownership:**
```bash
sudo chown pi:pi myfile
```
**User management:**
```bash
whoami
sudo adduser student
```
---
### 🔗 5. **Remote Access: SSH and VNC**
* **SSH** (for terminal access over network)
* **VNC** (for GUI desktop access)
#### ✅ Enable SSH & VNC:
```bash
sudo raspi-config
# Go to "Interface Options" > Enable SSH and VNC
```
Alternatively:
```bash
sudo systemctl enable ssh
sudo systemctl start ssh
```
#### 🖥️ Install VNC Viewer on PC/Mac:
* Download: [https://www.realvnc.com/en/connect/download/viewer](https://www.realvnc.com/en/connect/download/viewer)
* Enter Raspberry Pi’s IP (e.g., `192.168.1.42`) and login
To check IP:
```bash
hostname -I
```
---
### 🛠️ **Activities**
1. **Create and Navigate Folders**
```bash
mkdir ~/projects/day2
cd ~/projects/day2
```
2. **Edit and View Files**
```bash
nano notes.txt
cat notes.txt
```
3. **Install Software**
```bash
sudo apt install figlet
figlet "Hello Pi"
```
4. **Enable SSH & VNC and connect from another device**
---
### 📋 **Homework**
* Try installing any fun terminal program (`cmatrix`, `sl`, etc.)
* Create a bash script named `myinfo.sh` that displays:
* Current user (`whoami`)
* Date/time (`date`)
* IP address (`hostname -I`)
---
### ✅ **Summary**
* Terminal is your gateway to full control in Linux.
* You can move, create, and edit files efficiently.
* With `apt`, you can install nearly anything.
* SSH and VNC let you work remotely from any device.
# LED Blinking with Raspberry Pi
To make an LED blink on a **Raspberry Pi**, you'll need:
---
### 🧰 **Hardware Requirements**
* Raspberry Pi (any model with GPIO)
* 1x LED
* 1x 330Ω resistor
* Breadboard and jumper wires
---
### ⚙️ **Wiring**
Connect like this:
| LED Pin | Connects to |
| --- | --- |
| Anode (+) | GPIO pin (e.g., GPIO 17) via resistor |
| Cathode (–) | GND on Raspberry Pi |
📌 **Example:**
* **GPIO 17** → Resistor → **LED anode**
* **LED cathode** → **GND**
---
### 💻 **Python Code to Blink LED**
You can use the `gpiozero` or `RPi.GPIO` library.
#### ✅ Using `gpiozero` (simpler):
```python
from gpiozero import LED
from time import sleep
led = LED(17) # GPIO pin 17
while True:
led.on()
sleep(1)
led.off()
sleep(1)
```
#### ✅ Using `RPi.GPIO`:
```python
import RPi.GPIO as GPIO
import time
LED_PIN = 17
GPIO.setmode(GPIO.BCM)
GPIO.setup(LED_PIN, GPIO.OUT)
try:
while True:
GPIO.output(LED_PIN, GPIO.HIGH)
time.sleep(1)
GPIO.output(LED_PIN, GPIO.LOW)
time.sleep(1)
except KeyboardInterrupt:
GPIO.cleanup()
```
---
### ▶️ **To Run the Script**
1. Save it as [`blink.py`](http://blink.py)
2. Open terminal and run:
```bash
python3 blink.py
```
---
Let me know if you want to:
* Control the LED via a **web interface**
* Blink with **different patterns**
* Use a **button** to control it
---
## LED.html
```javascript
LED Control
LED Control
Current LED status: {{ 'ON' if status else 'OFF' }}