🕊️ Domain Availability Checker

A lightweight Bash script that checks domain name availability using whois lookups. Supports single lookups, bulk checking from a file, and ships with a small built-in example list for quick testing.

Features

• Single domain lookup — instant check for one domain
• File-based bulk checking — feed it a .txt file with one domain per line
• Built-in examples — run with no arguments to verify everything works
• Colour-coded output — green for available, red for taken, yellow for uncertain
• Rate-limit friendly — 1.5s delay between lookups to avoid getting blocked
• Comment support — organise your domain files with # comments and blank lines

Prerequisites

The script requires whois to be installed on your system.

# Debian / Ubuntu
sudo apt install whois

# macOS (Homebrew)
brew install whois

# Arch Linux
sudo pacman -S whois

Installation

git clone https://github.com/your-username/domain-checker.git
cd domain-checker
chmod +x check_domains.sh

Usage

Check a single domain

./check_domains.sh example.com

🕊️  Domain Availability Checker — Single Lookup
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ❌ TAKEN      example.com

Check domains from a file

./check_domains.sh -f domains.txt

🕊️  Domain Availability Checker — File: domains.txt (8 domains)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✅ AVAILABLE  my-awesome-startup.com
  ✅ AVAILABLE  cool-project-name.com
  ✅ AVAILABLE  definitely-available-12345.com
  ...

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Summary:
  Available: 5
  Taken:     2
  Unknown:   1

🎯 Available domains:
  → my-awesome-startup.com
  → cool-project-name.com
  → definitely-available-12345.com
  ...

Run built-in examples

./check_domains.sh

This runs a small set of hardcoded test domains to verify the script is working correctly.

Domain File Format

Create a plain text file with one domain per line. Comments (#) and blank lines are supported for organisation.

# Primary choices
mybrand.com
mybrand.io

# Alternatives
mybrand-app.com
getmybrand.com

# Known taken (for sanity checking)
google.com

See domains.example.txt for a ready-to-use template.

How It Works

The script queries whois for each domain and pattern-matches the response to determine availability:

Result	Meaning
✅ AVAILABLE	whois returned "not found" / "no match" indicators
❌ TAKEN	whois returned registrar / nameserver / creation date info
❓ UNKNOWN	Response didn't match either pattern — check manually

Note: whois responses vary by registrar and TLD. Some TLDs (especially newer ones) may return non-standard responses that land in the UNKNOWN bucket. When in doubt, verify manually with your registrar of choice.

Limitations

• Rate limiting — Some whois servers will throttle or block you if you hammer them. The built-in 1.5s delay helps, but very large lists may still hit limits.
• Accuracy — whois pattern matching is best-effort. Premium/reserved domains may show as available. Always confirm with a registrar before purchasing.
• TLD coverage — Works well with .com, .io, .co, .net, .org and most common TLDs. Newer or country-specific TLDs may need manual verification.

License

MIT