README.md

VPS Setup Script for Bun Applications

An automated setup script for deploying Bun applications on a VPS with Nginx reverse proxy, SSL, and PM2 process management.

Features

• 🚀 One-command setup for Bun applications
• 🔒 Automatic SSL certificate configuration via Let's Encrypt
• 🔄 Nginx reverse proxy with optimized settings
• 📊 PM2 process management
• 🛡️ Basic firewall configuration
• 🔄 Automatic rollback on error
• 📝 Detailed logging

Prerequisites

• Ubuntu/Debian-based VPS
• Root access
• Domain name pointing to your server's IP
• SSH access to your VPS

Quick Start

1. SSH into your VPS
2. Run the installation command:

bash <(curl -fsSL https://gist.githubusercontent.com/trvswgnr/77e7c59f8893dbc690fc4d5f05683d9c/raw/setup-vps-bun.sh)

What Gets Installed

• Nginx web server
• Certbot for SSL certificates
• Node.js and npm
• Bun runtime
• PM2 process manager
• Basic firewall rules

Directory Structure

/var/www/{your-domain}/
├── package.json
├── server.js
└── node_modules/

Configuration

The script will prompt you for:

• Domain name
• Email address (for SSL certificates)

Post-Installation

After successful installation:

1. Your application will be available at https://your-domain.com
2. Application files are located in /var/www/your-domain/
3. PM2 process management:

   pm2 status    # Check application status
   pm2 logs      # View application logs

Reverting Changes

To remove all changes made by the setup script:

1. SSH into your VPS
2. Run the same script with the --revert flag (coming soon)

Logging

• All operations are logged to /var/log/vps-setup.log
• View real-time logs during installation

Security Features

• 🔒 Automatic SSL/TLS configuration
• 🛡️ Basic firewall rules
• 🚫 Rate limiting
• 🔐 Security headers
• 🤖 Bot protection

Troubleshooting

1. SSL Certificate Issues

   • Ensure DNS is properly configured
   • Wait for DNS propagation (up to 48 hours)
   • Check certbot logs

2. Application Not Starting

   • Check PM2 logs: pm2 logs
   • Verify Bun installation: bun --version
   • Check nginx logs: /var/log/nginx/error.log

3. To manually roll back changes made by the setup script, you can run this script:

bash <(curl -fsSL https://gist.githubusercontent.com/trvswgnr/77e7c59f8893dbc690fc4d5f05683d9c/raw/undo-setup-vps-bun.sh)

License

MIT License

Author

Travis Aaron Wagner
Email: [email protected]

Version

Current Version: 0.3.0

---

⭐ Star this if you find it helpful!

setup-vps-bun.sh

#!/bin/bash

#===============================================================================
# Title: VPS Setup Script for Bun Applications
# Description: Automated setup script for deploying Bun applications on a VPS
#              with Nginx reverse proxy, SSL, and PM2 process management.
#
# Author: Travis Aaron Wagner <[email protected]>
# Version: 0.3.0
#
# Dependencies:
#   - Ubuntu/Debian-based system
#   - Root access
#   - Internet connection
#
# Usage:
#   1. ssh into your VPS
#   2. Run the following command:
#      `bash <(curl -fsSL https://techsavvytravvy.com/public/setup-vps-bun.sh)`
#
# Features:
#   - Automated system updates
#   - Nginx installation and configuration
#   - SSL certificate setup via Let's Encrypt
#   - Bun runtime installation
#   - PM2 process manager setup
#   - Basic firewall configuration
#   - Automatic application directory structure
#   - Reverse proxy configuration
#   - Full revert capability
#
# Notes:
#   - Requires valid domain name pointing to server IP
#   - Assumes clean Ubuntu/Debian installation
#   - Creates application in /var/www/{domain}
#   - Logs to /var/log/vps-setup.log
#
# License: MIT
#===============================================================================

## SETUP SCRIPT

VERSION="0.3.0"

# Exit on error, but allow for proper error handling
set -eo pipefail

# Configuration variables
LOG_FILE="/var/log/vps-setup.log"
DOMAIN="" # set by user input
NGINX_AVAILABLE="/etc/nginx/sites-available"
NGINX_ENABLED="/etc/nginx/sites-enabled"
APP_ROOT="/var/www"
SERVER_IP=$(curl -s4 ifconfig.me)
ADMIN_EMAIL="" # set by user input
NODE_ENV="production"
BUN_PORT=3000

# Color codes for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Logging function
log() {
    local level=$1
    shift
    local message="$*"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    echo -e "${timestamp} [${level}] ${message}" | tee -a "$LOG_FILE"
}

# Success message with checkmark
success() {
    echo -e "${GREEN}✓ $1${NC}" | tee -a "$LOG_FILE"
}

# Error message with ✗
error() {
    echo -e "${RED}✗ $1${NC}" | tee -a "$LOG_FILE"
    exit 1
}

# Warning message with !
warn() {
    echo -e "${YELLOW}! $1${NC}" | tee -a "$LOG_FILE"
}

# Check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Check if running as root
check_root() {
    if [[ $EUID -ne 0 ]]; then
        error "This script must be run as root"
    fi
}

# Validate domain name
validate_domain() {
    if [[ ! $1 =~ ^[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?(\.[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?)*\.[a-zA-Z]{2,}$ ]]; then
        error "Invalid domain name format"
        return 1
    fi
    return 0
}

# Get domain name from user
get_domain() {
    while true; do
        read -p "Enter your domain name (without www): " DOMAIN
        if validate_domain "$DOMAIN"; then
            success "Domain name validated: $DOMAIN"
            break
        else
            warn "Please enter a valid domain name"
        fi
    done
}

# Update system packages
update_system() {
    log "INFO" "Checking for system updates..."
    if ! apt update; then
        error "Failed to check for updates"
    fi
    
    # Check if any upgrades are available
    if apt list --upgradable 2>/dev/null | grep -q "upgradable"; then
        log "INFO" "Updates available, upgrading system packages..."
        if apt upgrade -y; then
            success "System packages updated"
        else
            error "Failed to update system packages"
        fi
    else
        success "System is already up to date"
    fi
}

# Install required packages
install_packages() {
    local packages=("nginx" "certbot" "python3-certbot-nginx" "curl" "unzip" "ca-certificates" "gnupg")
    
    for package in "${packages[@]}"; do
        if ! dpkg -s "$package" >/dev/null 2>&1; then
            log "INFO" "Installing $package..."
            if apt install -y "$package"; then
                success "$package installed"
            else
                error "Failed to install $package"
            fi
        else
            warn "$package is already installed"
        fi
    done
}

# Install Node.js
install_nodejs() {
    if ! command_exists node; then
        log "INFO" "Installing Node.js..."
        
        # Install Node.js from Ubuntu's default repository
        apt update
        apt install -y nodejs npm
        success "Node.js installed"
    else
        warn "Node.js is already installed"
    fi
}

# Install Bun
install_bun() {
    if ! command_exists bun; then
        log "INFO" "Installing Bun..."
        curl -fsSL https://bun.sh/install | bash
        
        # Add Bun to PATH for the current session
        export BUN_INSTALL="$HOME/.bun"
        export PATH=$BUN_INSTALL/bin:$PATH
        
        # Add Bun to PATH permanently
        if ! grep -q "BUN_INSTALL" /root/.bashrc; then
            echo 'export BUN_INSTALL="$HOME/.bun"' >> /root/.bashrc
            echo 'export PATH=$BUN_INSTALL/bin:$PATH' >> /root/.bashrc
        fi
        
        success "Bun installed"
    else
        warn "Bun is already installed"
    fi
}

# Install PM2
install_pm2() {
    if ! command_exists pm2; then
        log "INFO" "Installing PM2..."
        if npm install -g pm2; then
            success "PM2 installed"
            
            # Set up PM2 startup script
            pm2 startup systemd -u root --hp /root
            success "PM2 startup configured"
        else
            error "Failed to install PM2"
        fi
    else
        warn "PM2 is already installed"
    fi
}

# Set up application directory and files
setup_application() {
    local app_dir="$APP_ROOT/$DOMAIN"
    
    # Create directory structure
    if [[ ! -d "$app_dir" ]]; then
        log "INFO" "Creating application directory structure..."
        mkdir -p "$app_dir"
        success "Directory structure created"
    else
        warn "Application directory already exists"
    fi

    # Create package.json
    if [[ ! -f "$app_dir/package.json" ]]; then
        log "INFO" "Creating package.json..."
        cat > "$app_dir/package.json" <<EOF
{
  "name": "${DOMAIN}-server",
  "version": "1.0.0",
  "type": "module",
  "scripts": {
    "start": "bun run server.js",
    "dev": "bun --hot run server.js"
  }
}
EOF
        success "package.json created"
    fi

    # Create server.js
    if [[ ! -f "$app_dir/server.js" ]]; then
        log "INFO" "Creating server.js..."
        cat > "$app_dir/server.js" <<EOF
const server = Bun.serve({
  port: ${BUN_PORT},
  async fetch(request) {
    return new Response("Hello from Bun on ${DOMAIN}!");
  },
});

console.log(\`Listening on http://localhost:\${server.port}\`);
EOF
        success "server.js created"
    fi

    # Set permissions
    log "INFO" "Setting directory permissions..."
    chown -R www-data:www-data "$app_dir"
    chmod -R 755 "$app_dir"
    success "Permissions set"

    # Install dependencies
    log "INFO" "Installing dependencies..."
    cd "$app_dir"
    bun install
    success "Dependencies installed"
}

# Configure nginx as reverse proxy
setup_nginx() {
    local nginx_conf="$NGINX_AVAILABLE/$DOMAIN"
    if [[ ! -f "$nginx_conf" ]]; then
        log "INFO" "Creating nginx configuration..."
        cat > "$nginx_conf" <<EOF
limit_req_zone \$binary_remote_addr zone=general:10m rate=30r/s;

server {
    listen 80;
    listen [::]:80;
    server_name $DOMAIN www.$DOMAIN;

    # Enhanced security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "no-referrer-when-downgrade" always;
    add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline' 'unsafe-eval'; frame-ancestors 'self';" always;
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=(), payment=()" always;

    # Additional security measures
    server_tokens off;

    # Enhanced gzip configuration
    gzip_comp_level 6;
    gzip_types application/json
               application/javascript
               application/x-javascript
               application/xml
               application/xml+rss
               text/css
               text/javascript
               text/plain
               text/xml
               image/svg+xml;
    gzip_proxied any;
    
    # Apply rate limiting
    limit_req zone=general burst=10 nodelay;

    # SSL configuration will be added by certbot
    
    # Optimize file serving
    client_max_body_size 10m;
    client_body_buffer_size 200K;
    client_header_buffer_size 2k;
    large_client_header_buffers 3 1k;
    
    # Timeouts
    client_header_timeout 60;
    client_body_timeout 60;
    keepalive_timeout 65;
    send_timeout 60;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied expired no-cache no-store private auth;

    # Reverse proxy to Bun server
    location / {
        proxy_pass http://localhost:${BUN_PORT};
        proxy_http_version 1.1;
        proxy_set_header Upgrade \$http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host \$host;
        proxy_cache_bypass \$http_upgrade;
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto \$scheme;
        proxy_set_header X-Request-ID \$request_id;

        proxy_next_upstream error timeout http_500 http_502 http_503 http_504;
        proxy_next_upstream_tries 2;

        # Enhanced timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 300s;  # Increased for long-running requests

        # WebSocket support
        proxy_buffering off;
    }

    # Block common vulnerability scanners and bad bots
    if (\$http_user_agent ~* (masscan|nmap|nikto|sqlmap|python|curl|wget|scanbot|bot|spider)) {
        return 403;
    }

    # Deny access to hidden files
    location ~ /\. {
        deny all;
        access_log off;
        log_not_found off;
    }

    # Caching for static files
    location ~* \.(jpg|jpeg|png|gif|ico|css|js|pdf|txt|woff2|woff|ttf)$ {
        expires 30d;
        add_header Cache-Control "public, no-transform, must-revalidate";
        access_log off;
        tcp_nodelay off;
        open_file_cache max=3000 inactive=120s;
        open_file_cache_valid 45s;
        open_file_cache_min_uses 2;
        open_file_cache_errors off;
    }

    # Additional security for PHP/sensitive files (if applicable)
    location ~ \.(php|env|git|sql|conf|log|ini)$ {
        deny all;
        return 404;
    }
}
EOF
        success "Nginx configuration created"
    else
        warn "Nginx configuration already exists"
    fi

    # Enable site
    local nginx_enabled="$NGINX_ENABLED/$DOMAIN"
    if [[ ! -L "$nginx_enabled" ]]; then
        log "INFO" "Enabling website..."
        ln -s "$nginx_conf" "$nginx_enabled"
        success "Website enabled"
    else
        warn "Website already enabled"
    fi

    # Remove default site if it exists
    local default_site="$NGINX_ENABLED/default"
    if [[ -L "$default_site" ]]; then
        log "INFO" "Removing default nginx site..."
        rm "$default_site"
        success "Default site removed"
    fi
}

# Configure firewall
setup_firewall() {
    if command_exists ufw; then
        log "INFO" "Configuring firewall..."
        ufw allow 'Nginx Full' >/dev/null 2>&1
        ufw --force enable >/dev/null 2>&1
        success "Firewall configured"
    else
        warn "UFW not installed, skipping firewall configuration"
    fi
}

# Set up PM2 process
setup_pm2_process() {
    local app_dir="$APP_ROOT/$DOMAIN"
    
    log "INFO" "Setting up PM2 process..."
    cd "$app_dir"
    
    # Start the application with PM2
    NODE_ENV=production pm2 start server.js --name "$DOMAIN-server" --interpreter "$(which bun)"
    
    # Save PM2 process list
    pm2 save
    
    success "PM2 process configured"
}

configure_ssl() {
    read -p "Enter an email address for SSL certificate notifications [admin@$DOMAIN]: " ADMIN_EMAIL
    ADMIN_EMAIL=${ADMIN_EMAIL:-"admin@$DOMAIN"}
    log "INFO" "Setting up SSL certificate..."
    if certbot --nginx -d "$DOMAIN" -d "www.$DOMAIN" --non-interactive --agree-tos --email "$ADMIN_EMAIL" --redirect; then
        success "SSL certificate installed"
    else
        warn "SSL certificate installation failed. Please make sure your DNS is properly configured and try again manually"
    fi
}

# Configure SSL
setup_ssl() {
    if command_exists certbot; then
        # check if domain is already properly configured
        if dig +short "$DOMAIN" | grep -q "$SERVER_IP"; then
            configure_ssl
            return 0
        fi

        echo
        echo "Before proceeding with SSL setup, please make sure your domain is properly configured:"
        echo "1. Your domain ($DOMAIN) should point to this server's IP: $SERVER_IP"
        echo "2. DNS changes may take up to 48 hours to propagate globally"
        echo
        
        while true; do
            read -p "Have you configured your DNS settings and verified they are working? (y/n): " DNS_READY
            case $DNS_READY in
                [Yy]* )
                    configure_ssl
                    break;;
                [Nn]* )
                    warn "Please configure your DNS settings first and run certbot manually later using:"
                    echo "certbot --nginx -d $DOMAIN -d www.$DOMAIN"
                    break;;
                * ) echo "Please answer yes or no.";;
            esac
        done
    else
        error "certbot is not installed on this system"
    fi
}

# Test nginx configuration
test_nginx() {
    log "INFO" "Testing nginx configuration..."
    if nginx -t; then
        success "Nginx configuration test passed"
        systemctl reload nginx
        success "Nginx reloaded"
    else
        error "Nginx configuration test failed"
    fi
}

# Main function
main() {
    echo "--------------------------"
    echo "VPS setup script v$VERSION"
    echo "--------------------------"
    echo

    # Create log file if it doesn't exist
    touch "$LOG_FILE"
    chmod 644 "$LOG_FILE"
    
    log "INFO" "Starting VPS setup script v$VERSION"
    
    # Check if running as root
    check_root
    
    # Get domain name
    get_domain
    
    # Run setup steps
    update_system
    install_packages
    install_nodejs
    install_bun
    install_pm2
    setup_application
    setup_nginx
    setup_firewall
    test_nginx
    setup_pm2_process
    setup_ssl
    
    log "INFO" "VPS setup completed successfully"
    
    echo
    echo "Setup completed! Next steps:"
    echo "1. Verify DNS settings point to this server's IP address"
    echo "2. Visit https://$DOMAIN to confirm the site is working"
    echo "3. Your Bun application is located at /var/www/$DOMAIN/"
    echo "4. Use 'pm2 status' to check the application status"
    echo "5. Use 'pm2 logs' to view application logs"
    echo
    echo "For help, check the log file at $LOG_FILE"
}

## REVERT SETUP SCRIPT

# Stop and remove PM2 processes
revert_pm2() {
    if command_exists pm2; then
        log "INFO" "Removing PM2 processes..."
        
        # Stop and delete the specific app
        pm2 delete "$DOMAIN-server" >/dev/null 2>&1 || warn "No PM2 process found for $DOMAIN-server"
        
        # Save PM2 process list
        pm2 save >/dev/null 2>&1
        
        # Remove PM2 startup script
        pm2 unstartup systemd >/dev/null 2>&1 || warn "PM2 startup script not found"
        
        # Uninstall PM2 globally
        if npm uninstall -g pm2; then
            success "PM2 uninstalled"
        else
            warn "Failed to uninstall PM2"
        fi
    else
        warn "PM2 not found, skipping PM2 reversion"
    fi
}

# Remove Bun installation
revert_bun() {
    if command_exists bun; then
        log "INFO" "Removing Bun..."
        
        # Remove Bun installation directory
        rm -rf "$HOME/.bun"
        
        # Remove Bun from PATH in bashrc
        sed -i '/export BUN_INSTALL/d' /root/.bashrc
        sed -i '/export PATH=\$BUN_INSTALL/d' /root/.bashrc
        
        success "Bun removed"
    else
        warn "Bun not found, skipping Bun reversion"
    fi
}

# Revert nginx configuration
revert_nginx() {
    local nginx_conf="$NGINX_AVAILABLE/$DOMAIN"
    local nginx_enabled="$NGINX_ENABLED/$DOMAIN"
    
    if [[ -f "$nginx_conf" ]]; then
        log "INFO" "Removing nginx configuration..."
        rm -f "$nginx_conf"
        success "Nginx configuration removed"
    else
        warn "No nginx configuration found for $DOMAIN"
    fi

    if [[ -L "$nginx_enabled" ]]; then
        log "INFO" "Disabling site in nginx..."
        rm -f "$nginx_enabled"
        success "Site disabled in nginx"
    else
        warn "No enabled site found for $DOMAIN in nginx"
    fi

    # Restore default site if removed
    local default_site="$NGINX_ENABLED/default"
    if [[ ! -L "$default_site" && -f "$NGINX_AVAILABLE/default" ]]; then
        log "INFO" "Restoring default nginx site..."
        ln -s "$NGINX_AVAILABLE/default" "$default_site"
        success "Default site restored"
    fi

    # Reload nginx to apply changes
    if nginx -t; then
        success "Nginx configuration test passed"
        systemctl reload nginx
        success "Nginx reloaded"
    else
        error "Nginx configuration test failed; please review manually"
    fi
}

# Revert application directory
revert_application_directory() {
    local app_dir="$APP_ROOT/$DOMAIN"
    
    if [[ -d "$app_dir" ]]; then
        log "INFO" "Removing application directory structure..."
        rm -rf "$app_dir"
        success "Application directory structure removed"
    else
        warn "No application directory found for $DOMAIN"
    fi
}

# Revert firewall configuration
revert_firewall() {
    if command_exists ufw; then
        log "INFO" "Reverting firewall configuration..."
        ufw delete allow 'Nginx Full' >/dev/null 2>&1
        success "Firewall rule reverted"
        warn "UFW was enabled by setup script; review firewall status as needed."
    else
        warn "UFW not installed, skipping firewall reversion"
    fi
}

# Remove SSL certificates if they were installed
revert_ssl() {
    if command_exists certbot; then
        log "INFO" "Revoking SSL certificate..."
        certbot delete --cert-name "$DOMAIN" >/dev/null 2>&1 || warn "SSL certificate for $DOMAIN not found"
        success "SSL certificate revoked (if existed)"
    else
        warn "Certbot not installed, skipping SSL reversion"
    fi
}

# Reload or restart Nginx
restart_nginx() {
    log "INFO" "Restarting Nginx..."
    if systemctl restart nginx; then
        success "Nginx restarted successfully"
    else
        error "Failed to restart Nginx; please review manually"
    fi
}

# Remove log files
remove_logs() {
    log "INFO" "Removing log files..."
    rm -f "$LOG_FILE"
    success "Log files removed"
}

# Main function
revert_main() {
    # Create log file if it doesn't exist
    touch "$LOG_FILE"
    chmod 644 "$LOG_FILE"
    
    # Confirm with the user before proceeding
    echo
    echo -e "${YELLOW}WARNING${NC} - This script will remove:"
    echo "  - The Bun server application"
    echo "  - PM2 process manager and its processes"
    echo "  - Bun runtime"
    echo "  - Node.js installation"
    echo "  - Nginx configurations"
    echo "  - SSL certificates"
    echo "  - Application files and directories"
    echo
    read -p "Are you sure you want to revert all changes made by the setup script? (Y/n): " CONFIRM
    CONFIRM=${CONFIRM:-"Y"}
    if [[ ! "$CONFIRM" =~ ^[Yy]$ ]]; then
        echo "Reversion cancelled."
        exit 0
    fi
    
    log "INFO" "Reverting..."

    # Run revert steps
    revert_pm2
    revert_bun
    revert_nginx
    revert_application_directory
    revert_firewall
    revert_ssl
    restart_nginx  # Apply nginx reload
    # remove_logs    # Clean up log file
    
    log "INFO" "VPS revert script completed successfully"
    
    echo
    echo "Revert completed! The changes made by the setup script for $DOMAIN have been reverted."
    echo "Note: Some system packages (nginx, certbot, etc.) were not removed."
    echo "If you want to remove them, use: apt remove nginx certbot python3-certbot-nginx"
    echo
    echo "For more details, check the log file at $LOG_FILE"
}

# Clean up function to revert if main fails
clean_up() {
    if [[ $? -ne 0 ]]; then
        revert_main
    fi
}

trap clean_up EXIT
main "$@"

undo-setup-vps-bun.sh

#!/bin/bash

VERSION="0.3.0"

# Exit on error
set -eo pipefail

# Configuration variables (should match the setup script)
OG_LOG_FILE="/var/log/vps-setup.log"
LOG_FILE="/var/log/vps-setup-revert.log"
DOMAIN="" # set by user input
NGINX_AVAILABLE="/etc/nginx/sites-available"
NGINX_ENABLED="/etc/nginx/sites-enabled"
APP_ROOT="/var/www"
ADMIN_EMAIL="" # set by user input

# Color codes for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Logging function
log() {
    local level=$1
    shift
    local message="$*"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    echo -e "${timestamp} [${level}] ${message}" | tee -a "$LOG_FILE"
}

# Success message with checkmark
success() {
    echo -e "${GREEN}✓ $1${NC}" | tee -a "$LOG_FILE"
}

# Error message with X
error() {
    echo -e "${RED}✗ $1${NC}" | tee -a "$LOG_FILE"
    return 1
}

# Warning message with !
warn() {
    echo -e "${YELLOW}! $1${NC}" | tee -a "$LOG_FILE"
}

# Check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Stop and remove PM2 processes
revert_pm2() {
    if command_exists pm2; then
        log "INFO" "Removing PM2 processes..."
        
        # Stop and delete the specific app
        pm2 delete "$DOMAIN-server" >/dev/null 2>&1 || warn "No PM2 process found for $DOMAIN-server"
        
        # Save PM2 process list
        pm2 save >/dev/null 2>&1
        
        # Remove PM2 startup script
        pm2 unstartup systemd >/dev/null 2>&1 || warn "PM2 startup script not found"
        
        # Uninstall PM2 globally
        if npm uninstall -g pm2; then
            success "PM2 uninstalled"
        else
            warn "Failed to uninstall PM2"
        fi
    else
        warn "PM2 not found, skipping PM2 reversion"
    fi
}

# Remove Bun installation
revert_bun() {
    if command_exists bun; then
        log "INFO" "Removing Bun..."
        
        # Remove Bun installation directory
        rm -rf "$HOME/.bun"
        
        # Remove Bun from PATH in bashrc
        sed -i '/export BUN_INSTALL/d' /root/.bashrc
        sed -i '/export PATH=\$BUN_INSTALL/d' /root/.bashrc
        
        success "Bun removed"
    else
        warn "Bun not found, skipping Bun reversion"
    fi
}

# Revert nginx configuration
revert_nginx() {
    local nginx_conf="$NGINX_AVAILABLE/$DOMAIN"
    local nginx_enabled="$NGINX_ENABLED/$DOMAIN"
    
    if [[ -f "$nginx_conf" ]]; then
        log "INFO" "Removing nginx configuration..."
        rm -f "$nginx_conf"
        success "Nginx configuration removed"
    else
        warn "No nginx configuration found for $DOMAIN"
    fi

    if [[ -L "$nginx_enabled" ]]; then
        log "INFO" "Disabling site in nginx..."
        rm -f "$nginx_enabled"
        success "Site disabled in nginx"
    else
        warn "No enabled site found for $DOMAIN in nginx"
    fi

    # Restore default site if removed
    local default_site="$NGINX_ENABLED/default"
    if [[ ! -L "$default_site" && -f "$NGINX_AVAILABLE/default" ]]; then
        log "INFO" "Restoring default nginx site..."
        ln -s "$NGINX_AVAILABLE/default" "$default_site"
        success "Default site restored"
    fi

    # Reload nginx to apply changes
    if nginx -t; then
        success "Nginx configuration test passed"
        systemctl reload nginx
        success "Nginx reloaded"
    else
        error "Nginx configuration test failed; please review manually"
    fi
}

# Revert application directory
revert_application_directory() {
    local app_dir="$APP_ROOT/$DOMAIN"
    
    if [[ -d "$app_dir" ]]; then
        log "INFO" "Removing application directory structure..."
        rm -rf "$app_dir"
        success "Application directory structure removed"
    else
        warn "No application directory found for $DOMAIN"
    fi
}

# Revert firewall configuration
revert_firewall() {
    if command_exists ufw; then
        log "INFO" "Reverting firewall configuration..."
        ufw delete allow 'Nginx Full' >/dev/null 2>&1
        success "Firewall rule reverted"
        warn "UFW was enabled by setup script; review firewall status as needed."
    else
        warn "UFW not installed, skipping firewall reversion"
    fi
}

# Remove SSL certificates if they were installed
revert_ssl() {
    if command_exists certbot; then
        log "INFO" "Revoking SSL certificate..."
        certbot delete --cert-name "$DOMAIN" >/dev/null 2>&1 || warn "SSL certificate for $DOMAIN not found"
        success "SSL certificate revoked (if existed)"
    else
        warn "Certbot not installed, skipping SSL reversion"
    fi
}

# Reload or restart Nginx
restart_nginx() {
    log "INFO" "Restarting Nginx..."
    if systemctl restart nginx; then
        success "Nginx restarted successfully"
    else
        error "Failed to restart Nginx; please review manually"
    fi
}

# Remove log files
remove_logs() {
    log "INFO" "Removing setup log files..."
    rm -f "$OG_LOG_FILE"
    success "Log files removed"
}

# Main function
main() {
    # Create log file if it doesn't exist
    touch "$LOG_FILE"
    chmod 644 "$LOG_FILE"
    
    # Confirm with the user before proceeding
    echo "WARNING: This script will remove:"
    echo "  - The Bun server application"
    echo "  - PM2 process manager and its processes"
    echo "  - Bun runtime"
    echo "  - Node.js installation"
    echo "  - Nginx configurations"
    echo "  - SSL certificates"
    echo "  - Application files and directories"
    echo
    read -p "Are you sure you want to revert all changes made by the setup script? (y/n): " CONFIRM
    if [[ ! "$CONFIRM" =~ ^[Yy]$ ]]; then
        echo "Reversion cancelled."
        exit 0
    fi
    
    log "INFO" "Starting VPS revert script"

    # Prompt for domain name
    while true; do
        read -p "Enter your domain name (without www): " DOMAIN
        if [[ ! $1 =~ ^[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?(\.[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?)*\.[a-zA-Z]{2,}$ ]]; then
            success "Domain name validated: $DOMAIN"
            break
        else
            warn "Invalid domain name format. Please try again."
        fi
    done

    # Run revert steps
    revert_pm2
    revert_bun
    revert_nginx
    revert_application_directory
    revert_firewall
    revert_ssl
    restart_nginx  # Apply nginx reload
    remove_logs    # Clean up log file
    
    log "INFO" "VPS revert script completed successfully"
    
    echo
    echo "Revert completed! The changes made by the setup script for $DOMAIN have been reverted."
    echo "Note: Some system packages (nginx, certbot, etc.) were not removed."
    echo "If you want to remove them, use: apt remove nginx certbot python3-certbot-nginx"
    echo
    echo "For any issues, check the log file at $LOG_FILE"
}

# Run main function
main "$@"

Cheers for this! Been wanting to learn nginx and set up a small hobby site on a VPS, so I'm basically treating this as a tutorial. The code is very readable.

One minor enhancement for getting the machine's IPv4 address:

hostname -I | awk '{print $1}'

Not sure how reliable this method is across different distros, but I figured it's a little safer than curl-ing a third-party site.