
### 🔧 **Service Management (Ubuntu-based systems)**

| Command                             | Description                             |
| ----------------------------------- | --------------------------------------- |
| `sudo systemctl start supervisor`   | Start the Supervisor service            |
| `sudo systemctl stop supervisor`    | Stop the Supervisor service             |
| `sudo systemctl restart supervisor` | Restart Supervisor                      |
| `sudo systemctl status supervisor`  | Check the status of Supervisor          |
| `sudo systemctl enable supervisor`  | Enable Supervisor to run at boot        |
| `sudo systemctl disable supervisor` | Disable Supervisor from running at boot |

---

### ⚙️ **Supervisor CLI Commands**

These use the `supervisorctl` command:

| Command                                | Description                                          |
| -------------------------------------- | ---------------------------------------------------- |
| `sudo supervisorctl`                   | Enter Supervisor interactive mode                    |
| `sudo supervisorctl status`            | View the status of all managed processes             |
| `sudo supervisorctl start <program>`   | Start a specific program                             |
| `sudo supervisorctl stop <program>`    | Stop a specific program                              |
| `sudo supervisorctl restart <program>` | Restart a specific program                           |
| `sudo supervisorctl reread`            | Reread config files (does **not** apply changes yet) |
| `sudo supervisorctl update`            | Apply changes after `reread` (add/remove programs)   |
| `sudo supervisorctl reload`            | Restart Supervisor and all managed processes         |
| `sudo supervisorctl shutdown`          | Gracefully shut down Supervisor daemon               |

---

### 📁 **Supervisor Config Locations (Ubuntu)**

| Path                               | Description                                        |
| ---------------------------------- | -------------------------------------------------- |
| `/etc/supervisor/supervisord.conf` | Main Supervisor config file                        |
| `/etc/supervisor/conf.d/`          | Directory to store individual program config files |

---

### 🛠️ **Example Workflow After Adding a New Program**

```bash
sudo supervisorctl reread
sudo supervisorctl update
sudo supervisorctl start your_program_name
```




### 🚀 **Basic Process Management**

| **Command**                                            | **Description**                                    |
| ------------------------------------------------------ | -------------------------------------------------- |
| `pm2 start app.js`                                     | Start a Node.js application                        |
| `pm2 start app.js --name my-app`                       | Start the app with a custom process name           |
| `pm2 list`                                             | List all running processes managed by PM2          |
| `pm2 show <id or name>` or `pm2 describe <id or name>` | Show detailed information about a specific process |
| `pm2 restart <id or name>`                             | Restart a specific process                         |
| `pm2 reload <id or name>`                              | Gracefully reload a process (zero downtime)        |
| `pm2 stop <id or name>`                                | Stop a specific process                            |
| `pm2 delete <id or name>`                              | Delete a process from the PM2 process list         |
| `pm2 delete all`                                       | Remove all processes from PM2 management           |


---

### 🔁 **Startup & Auto-Restart**

| Command         | Description                                              |
| --------------- | -------------------------------------------------------- |
| `pm2 startup`   | Generate and configure PM2 to launch on system boot      |
| `pm2 save`      | Save current process list for automatic reload on reboot |
| `pm2 resurrect` | Restore processes saved via `pm2 save`                   |

---

### 📈 **Monitoring & Logs**

| **Command**             | **Description**                                     |
| ----------------------- | --------------------------------------------------- |
| `pm2 monit`             | Launch PM2's real-time process monitoring dashboard |
| `pm2 logs`              | Show logs for all processes                         |
| `pm2 logs <id or name>` | Show logs for a specific process                    |
| `pm2 flush`             | Clear all logs                                      |
| `pm2 reloadLogs`        | Reload logs in real-time                            |

---

### 🛠️ **Miscellaneous**

| **Command**                      | **Description**                                   |
| -------------------------------- | ------------------------------------------------- |
| `pm2 env <id or name>`           | Show environment variables for a specific process |
| `pm2 reload ecosystem.config.js` | Reload all apps defined in an ecosystem file      |
| `pm2 start ecosystem.config.js`  | Start all apps from an ecosystem file             |





A complete and beginner-friendly guide to install **Certbot Let’s Encrypt SSL** on **Ubuntu servers with NGINX**, enabling free **HTTPS encryption** with **automatic certificate renewal**.

---

## 📦 Installing Certbot on Ubuntu 16.04

For users running Ubuntu 16.04, execute the following commands:

```bash
apt-get update
sudo apt-get install certbot
sudo apt-get install python-certbot-nginx
```

---

## 📦 Installing Certbot on Ubuntu 18.04 and Later

For Ubuntu 18.04 or any newer version, run the following:

```bash
apt-get update
sudo apt-get install certbot
sudo apt-get install python3-certbot-nginx
```

---

## 🌐 Obtain a Let’s Encrypt SSL Certificate for NGINX

Once Certbot is installed, use this command to **automatically configure HTTPS for your domain**:

```bash
sudo certbot --nginx -d example.com
```

Replace `example.com` with your actual domain name.

---

## 🔁 Automatically Renew Let’s Encrypt SSL Certificates

To ensure your SSL certificates are **renewed automatically**, add a cron job as follows:

### Edit Crontab

```bash
crontab -e
```

### Add the Following Line

```bash
0 12 * * * /usr/bin/certbot renew --quiet
```

This command runs the renewal process **daily at 12:00 PM**.

---

## ✅ Conclusion

Your website is now secured with **free HTTPS using Let’s Encrypt**, and the SSL certificate will automatically renew without manual intervention.



### 🔧 **Service Management**

Use `sudo` if you're not logged in as root.

| Command                        | Description                                       |
| ------------------------------ | ------------------------------------------------- |
| `sudo systemctl start nginx`   | Start the Nginx service                           |
| `sudo systemctl stop nginx`    | Stop the Nginx service                            |
| `sudo systemctl restart nginx` | Restart Nginx and reload all configs              |
| `sudo systemctl reload nginx`  | Reload config without dropping active connections |
| `sudo systemctl status nginx`  | Check the current status of Nginx                 |
| `sudo systemctl enable nginx`  | Enable Nginx to start at boot                     |
| `sudo systemctl disable nginx` | Disable Nginx from auto-starting at boot          |

---

### ⚙️ **Configuration & Testing**

| Command                | Description                                 |
| ---------------------- | ------------------------------------------- |
| `sudo nginx -t`        | Test Nginx configuration for syntax errors  |
| `sudo nginx -s reload` | Reload Nginx via CLI                        |
| `sudo nginx -s stop`   | Stop Nginx via CLI                          |
| `sudo nginx -s quit`   | Gracefully shut down Nginx                  |
| `nginx -v`             | Show Nginx version                          |
| `nginx -V`             | Show version with build options and modules |

---

### 📁 **Default Configuration Paths (Ubuntu)**

| Path                          | Description                                                    |
| ----------------------------- | -------------------------------------------------------------- |
| `/etc/nginx/nginx.conf`       | Main Nginx config file                                         |
| `/etc/nginx/sites-available/` | Directory for available virtual host configs                   |
| `/etc/nginx/sites-enabled/`   | Directory for enabled sites (symlinked from `sites-available`) |
| `/var/www/html/`              | Default web root directory                                     |

---

### 🛠️ **Extra Tips**

* After editing the config:

  ```bash
  sudo nginx -t && sudo systemctl reload nginx
  ```

* To view logs:

  ```bash
  tail -f /var/log/nginx/access.log
  tail -f /var/log/nginx/error.log
  ```


Shorts