4000.md
root@localhost:~# cat 4000.md

# Services and Software That Use Port 4000

## Static Site Generators

• Jekyll
Ruby-based static site generator that defaults to port 4000 for its development server with live reload capabilities.
• Hugo
Fast static site generator that can be configured to use port 4000 as an alternative to its default port.
• Gatsby
React-based static site generator that can be configured to develop on port 4000.
• Middleman
Ruby static site generator that often uses port 4000 for local development.

## Ruby Applications

• Ruby on Rails
Rails development servers configured to run on port 4000 when default ports are occupied.
• Sinatra
Lightweight Ruby web framework applications commonly configured on port 4000.
• Puma Server
Ruby web server that can be configured to serve applications on port 4000.

## Development Tools

• GitHub Pages Local
Local development environment for GitHub Pages sites using Jekyll on port 4000.
• Bundler Server
Ruby gem bundler's development server functionality on port 4000.
• WEBrick
Ruby's built-in web server that can be configured to run on port 4000.
• Rack Server
Ruby Rack-based applications development server running on port 4000.

## Alternative Web Servers

• Node.js Express
Express.js applications configured to use port 4000 when other ports are occupied.
• Python Flask
Flask development servers configured on port 4000 for testing and development.
• PHP Development Server
PHP built-in development server configured to use port 4000.

# Frequently Asked Questions

Q: Why does Jekyll use port 4000 by default?

A:

Jekyll chose port 4000 as it's memorable, high enough to avoid system services, doesn't require root privileges, and wasn't commonly used by other development tools when Jekyll was created. It has since become the standard for Jekyll development.

Q: How to change Jekyll's default port from 4000?

A:

Use the --port flag when starting Jekyll: 'bundle exec jekyll serve --port 4001'. You can also set the port in your _config.yml file with 'port: 4001' or use the JEKYLL_PORT environment variable.

Q: How to access Jekyll site from other devices on network?

A:

Start Jekyll with --host 0.0.0.0: 'bundle exec jekyll serve --host 0.0.0.0'. Then access your site using your computer's IP address: http://192.168.1.100:4000 (replace with your actual IP).

Q: Why choose Jekyll over other static site generators?

A:

Jekyll integrates seamlessly with GitHub Pages, has a large community, excellent documentation, and robust plugin ecosystem. It's particularly good for blogs and documentation sites, with built-in support for Markdown and Liquid templating.

Q: Can I deploy Jekyll sites from localhost:4000 to production?

A:

Port 4000 is only for development. For production, Jekyll generates static files that can be served by any web server (nginx, Apache) on standard ports 80/443. Use 'jekyll build' to generate the production site in the _site directory.

Q: How to enable HTTPS for Jekyll development on port 4000?

A:

Jekyll doesn't natively support HTTPS. For HTTPS development, use a reverse proxy like nginx or run Jekyll behind a local development proxy. Alternatively, use tools like ngrok to create secure tunnels to your localhost:4000.

Q: How to test GitHub Pages site locally on port 4000?

A:

Install the github-pages gem and use 'bundle exec jekyll serve' to run your GitHub Pages site locally on port 4000. This ensures your local environment matches GitHub's Jekyll version and plugins.

Q: Can I run multiple Jekyll sites simultaneously?

A:

Yes, each Jekyll site needs a different port. The first site uses port 4000, and subsequent sites automatically increment (4001, 4002, etc.) or you can specify ports manually with --port flag.

# How to Use Port 4000

1.

Install Jekyll or Setup Project

Install Jekyll and create a new site, or navigate to your existing Jekyll project directory. Ensure all dependencies are properly installed.

bash
gem install jekyll bundler && jekyll new my-site
2.

Check Port Availability

Verify that port 4000 is available before starting the development server. Jekyll will use this port by default.

bash
lsof -i :4000
3.

Start Jekyll Development Server

Launch the Jekyll development server which will automatically serve your site on port 4000 with live reload functionality.

bash
bundle exec jekyll serve
4.

Access Your Site

Open your web browser and navigate to http://localhost:4000 to view your Jekyll site. The server will automatically detect file changes and reload.

bash
curl http://localhost:4000
5.

Configure Alternative Port

If port 4000 is occupied, you can specify an alternative port using the --port flag when starting the Jekyll server.

bash
bundle exec jekyll serve --port 4001

# Common Problems

## HIGH Severity Issues

⚠ Jekyll Server Won't Start

Jekyll fails to start on port 4000 due to missing dependencies, Ruby version conflicts, or gem installation issues. This is common with Ruby environment problems.

⚠ Ruby Version Compatibility

Jekyll on port 4000 fails to start due to Ruby version incompatibilities or outdated gem versions, common in mixed development environments.

## MEDIUM Severity Issues

⚠ Port 4000 Already in Use

Another Jekyll instance or different application is using port 4000, preventing your development server from starting. Jekyll will usually suggest using port 4001.

⚠ Live Reload Not Working

File changes aren't automatically reflected in the browser when using Jekyll's development server on port 4000, often due to file watching issues.

⚠ Site Generation Errors

Jekyll encounters build errors that prevent the site from being served on port 4000, typically related to liquid template syntax or markdown parsing.

# Troubleshooting Solutions

## All Platform

Fix Jekyll Startup Issues

For: Jekyll Server Won't Start

Steps:

  1. Check Ruby version and ensure it's compatible with Jekyll
  2. Update or reinstall Jekyll and bundler gems
  3. Verify all project dependencies are installed
all
ruby --version && gem --version

Fix Jekyll Startup Issues

For: Jekyll Server Won't Start

Steps:

  1. Check Ruby version and ensure it's compatible with Jekyll
  2. Update or reinstall Jekyll and bundler gems
  3. Verify all project dependencies are installed
all
gem update jekyll bundler

Fix Jekyll Startup Issues

For: Jekyll Server Won't Start

Steps:

  1. Check Ruby version and ensure it's compatible with Jekyll
  2. Update or reinstall Jekyll and bundler gems
  3. Verify all project dependencies are installed
all
bundle install

Enable Jekyll Live Reload

For: Live Reload Not Working

Steps:

  1. Start Jekyll with live reload and incremental regeneration flags
  2. Check if file watching is working properly on your system
  3. Verify browser isn't caching old versions of your site
all
bundle exec jekyll serve --livereload --incremental

Enable Jekyll Live Reload

For: Live Reload Not Working

Steps:

  1. Start Jekyll with live reload and incremental regeneration flags
  2. Check if file watching is working properly on your system
  3. Verify browser isn't caching old versions of your site
all
bundle exec jekyll serve --force_polling

Enable Jekyll Live Reload

For: Live Reload Not Working

Steps:

  1. Start Jekyll with live reload and incremental regeneration flags
  2. Check if file watching is working properly on your system
  3. Verify browser isn't caching old versions of your site
all
bundle exec jekyll serve --host 0.0.0.0

# Summary

root@localhost:~# echo "Port 4000 Documentation Complete"

What it is: localhost:4000 is Localhost:4000 is the default development port for Jekyll static site generator and is widely used by Ruby-based web applications. This port is particularly popular in the Ruby ecosystem and for static site development, offering a clean and memorable alternative for development servers.

Who uses it: Jekyll, Hugo, Gatsby, Middleman, Ruby on Rails, Sinatra, Puma Server, GitHub Pages Local, Bundler Server, WEBrick, Rack Server, Node.js Express, Python Flask, PHP Development Server

Access URL: http://localhost:4000