Local File Checking with --root-dir

What Does —root-dir Do?

The --root-dir parameter tells lychee where to look for files that start with /. Let’s see an example:

index.html

<!-- index.html -->
<a href="/about.html">About</a>
<a href="/docs/guide.html">Guide</a>

These links start with /, meaning they’re absolute paths.

If the site is built in a public directory, the files will be in public/about.html and public/docs/guide.html. To check these links, you’d run:

lychee --root-dir "$(pwd)/public" "**/*.html"

lychee will look for:

• ./public/about.html
• ./public/docs/guide.html

When Do You Need —root-dir?

You need --root-dir when:

1. Your HTML contains links starting with /
2. You want to check these links against files on your computer

Common scenarios:

• Static site builds in a public or dist directory
• Documentation sites with absolute links
• Any project where links start with /

Note

--root-dir must be an absolute path. If you provide a relative path, lychee will error.

# ✅ Good
lychee --root-dir /home/user/project/public/

# ❌ Bad: will fail
lychee --root-dir ./public/

This is a conservative solution to prevent edge cases. If you have a use case for allowing relative root directories, please open an issue.

Examples

Static Site Builder

If you use Hugo, Jekyll, or similar tools, they often generate sites in a public directory:

my-site/
├── public/           # Generated files live here
│   ├── about.html
│   └── docs/
│       └── guide.html
└── content/          # Source files
    └── index.md

To check the links:

# Convert relative path to absolute first
lychee --root-dir "$(pwd)/public" "public/**/*.html"

Documentation Site

Many documentation sites use absolute paths for links:

docs/index.html

<!-- docs/index.html -->
<a href="/api/v1.html">API</a>
<a href="/guide/start.html">Get Started</a>

To check these links:

# Assuming you're in the project root
lychee --root-dir "$(pwd)" "docs/**/*.html"

The Difference Between —root-dir and —base

These parameters serve different purposes:

• --root-dir is for finding files on your computer

  • Only affects links that start with /
  • Must be an absolute filesystem path
  • Used when checking local files

• --base is for resolving URLs

  • Must be a URL (like https://example.com/docs/)
  • Used when checking how links will work once deployed
  • Affects relative links (like ./guide.html)

Using Both Together

Sometimes you need both:

lychee \
  --root-dir "$(pwd)/public" \
  --base https://example.com/ \
  "public/**/*.html"

This tells lychee:

1. Look for /-prefixed files in ./public/
2. Resolve relative links against https://example.com/

Troubleshooting

If your links aren’t being found:

1. Make sure you’re using an absolute path:

# Get absolute path in bash
full_path="$(pwd)/public"
lychee --root-dir "$full_path" "**/*.html"

2. Check that the files exist in the location you expect:

# Example debugging steps
ls -la ./public/about.html
ls -la ./public/docs/guide.html

3. Use --verbose to see how lychee is resolving paths:

lychee --root-dir "$(pwd)/public" --verbose "**/*.html"