Give me 3 medium-difficulty technical experiment topics for the Linux system.Please translate the following text into English. Tell me the answer and list each step.

Sure! Here are three medium-difficulty technical experiment topics for the Linux system:

### 1. Set Up a LAMP Stack
**Description:** Install and configure a Linux, Apache, MySQL, and PHP (LAMP) stack on a Linux machine.

**Steps:**
1. **Update the package index:**
   ```bash
   sudo apt update
   ```
2. **Install Apache:**
   ```bash
   sudo apt install apache2
   ```
3. **Install MySQL:**
   ```bash
   sudo apt install mysql-server
   ```
4. **Secure MySQL installation:**
   ```bash
   sudo mysql_secure_installation
   ```
5. **Install PHP and related modules:**
   ```bash
   sudo apt install php libapache2-mod-php php-mysql
   ```
6. **Restart Apache server:**
   ```bash
   sudo systemctl restart apache2
   ```
7. **Create a test PHP file:**
   ```bash
   echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php
   ```
8. **Access the test page:** Open your web browser and navigate to `http://your_server_ip/info.php`.

### 2. Create a Simple Firewall with UFW
**Description:** Configure a basic firewall using Uncomplicated Firewall (UFW) to restrict access to your server.

**Steps:**
1. **Install UFW (if not pre-installed):**
   ```bash
   sudo apt install ufw
   ```
2. **Check UFW status:**
   ```bash
   sudo ufw status
   ```
3. **Allow SSH connections:**
   ```bash
   sudo ufw allow ssh
   ```
4. **Allow HTTP and HTTPS traffic:**
   ```bash
   sudo ufw allow http
   sudo ufw allow https
   ```
5. **Enable UFW:**
   ```bash
   sudo ufw enable
   ```
6. **Verify UFW status and rules:**
   ```bash
   sudo ufw status verbose
   ```

### 3. Create a Bash Script for Automated Backups
**Description:** Write a Bash script to automate the backup of specific directories to a designated backup location.

**Steps:**
1. **Create a new Bash script file:**
   ```bash
   nano backup_script.sh
   ```
2. **Add the following script:**
   ```bash
   #!/bin/bash
   BACKUP_DIR="/path/to/backup"
   SOURCE_DIR="/path/to/source"
   DATE=$(date +%Y%m%d_%H%M%S)
   tar -czf ${BACKUP_DIR}/backup_${DATE}.tar.gz -C ${SOURCE_DIR} .
   ```
3. **Make the script executable:**
   ```bash
   chmod +x backup_script.sh
   ```
4. **Run the script:**
   ```bash
   ./backup_script.sh
   ```
5. **Verify the backup:**
   List the contents of the backup directory:
   ```bash
   ls -lh /path/to/backup
   ```

Feel free to elaborate on any of these topics or experiment with additional features to enhance your learning!