Command-Line Flags

lychee is a fast, asynchronous link checker which detects broken URLs and mail addresses in local files and websites. It supports Markdown and HTML and works well with many plain text file formats.

lychee is powered by lychee-lib, the Rust library for link checking.

Usage:

lychee [OPTIONS] [inputs]...

Arguments

[inputs]…

lychee [inputs]...

Inputs for link checking (where to get links to check from). These can be: files (e.g. README.md), file globs (e.g. '~/git/*/README.md'), remote URLs (e.g. https://example.com/README.md), or standard input (-). Alternatively, use --files-from to read inputs from a file.

NOTE: Use -- to separate inputs from options that allow multiple arguments.

Options

-a, --accept

lychee --accept <ACCEPT>

A List of accepted status codes for valid links

The following accept range syntax is supported: [start]..[[=]end]|code. Some valid examples are:

200 (accepts the 200 status code only)
..204 (accepts any status code < 204)
..=204 (accepts any status code <= 204)
200..=204 (accepts any status code from 200 to 204 inclusive)
200..205 (accepts any status code from 200 to 205 excluding 205, same as 200..=204)

Use “lychee --accept ‘200..=204, 429, 500’ …” to provide a comma- separated list of accepted status codes. This example will accept 200, 201, 202, 203, 204, 429, and 500 as valid status codes.

default: 100..=103,200..=299

--archive

lychee --archive <ARCHIVE>

Specify the use of a specific web archive. Can be used in combination with --suggest

possible values: wayback

-b, --base-url

lychee --base-url <BASE_URL>

Base URL to use when resolving relative URLs in local files. If specified, relative links in local files are interpreted as being relative to the given base URL.

For example, given a base URL of https://example.com/dir/page, the link a would resolve to https://example.com/dir/a and the link /b would resolve to https://example.com/b. This behavior is not affected by the filesystem path of the file containing these links.

Note that relative URLs without a leading slash become siblings of the base URL. If, instead, the base URL ended in a slash, the link would become a child of the base URL. For example, a base URL of https://example.com/dir/page/ and a link of a would resolve to https://example.com/dir/page/a.

Basically, the base URL option resolves links as if the local files were hosted at the given base URL address.

The provided base URL value must either be a URL (with scheme) or an absolute path. Note that certain URL schemes cannot be used as a base, e.g., data and mailto.

--base

lychee --base <BASE>

Deprecated; use --base-url instead

--basic-auth

lychee --basic-auth <BASIC_AUTH>

Basic authentication support. E.g. http://example.com username:password

-c, --config

lychee --config <CONFIG_FILE>

Configuration file to use

default: lychee.toml

--cache

lychee --cache

Use request cache stored on disk at .lycheecache

--cache-exclude-status

lychee --cache-exclude-status <CACHE_EXCLUDE_STATUS>

A list of status codes that will be ignored from the cache

The following exclude range syntax is supported: [start]..[[=]end]|code. Some valid examples are:

429 (excludes the 429 status code only)
500.. (excludes any status code >= 500)
..100 (excludes any status code < 100)
500..=599 (excludes any status code from 500 to 599 inclusive)
500..600 (excludes any status code from 500 to 600 excluding 600, same as 500..=599)

Use “lychee --cache-exclude-status ‘429, 500..502’ …” to provide a comma-separated list of excluded status codes. This example will not cache results with a status code of 429, 500 and 501.

lychee --cookie-jar <COOKIE_JAR>

Tell lychee to read cookies from the given file. Cookies will be stored in the cookie jar and sent with requests. New cookies will be stored in the cookie jar and existing cookies will be updated.

--default-extension

lychee --default-extension <EXTENSION>

This is the default file extension that is applied to files without an extension.

This is useful for files without extensions or with unknown extensions. The extension will be used to determine the file type for processing. Examples: --default-extension md, --default-extension html

--dump

lychee --dump

Don’t perform any link checking. Instead, dump all the links extracted from inputs that would be checked

--dump-inputs

lychee --dump-inputs

Don’t perform any link extraction and checking. Instead, dump all input sources from which links would be collected

-E, --exclude-all-private

lychee --exclude-all-private

Exclude all private IPs from checking. Equivalent to --exclude-private --exclude-link-local --exclude-loopback

--exclude

lychee --exclude <EXCLUDE>

Exclude URLs and mail addresses from checking. The values are treated as regular expressions

--exclude-file

lychee --exclude-file <EXCLUDE_FILE>

Deprecated; use --exclude-path instead

--exclude-link-local

lychee --exclude-link-local

Exclude link-local IP address range from checking

--exclude-loopback

lychee --exclude-loopback

Exclude loopback IP address range and localhost from checking

--exclude-path

lychee --exclude-path <EXCLUDE_PATH>

Exclude paths from getting checked. The values are treated as regular expressions

--exclude-private

lychee --exclude-private

Exclude private IP address ranges from checking

--extensions

lychee --extensions <EXTENSIONS>

Test the specified file extensions for URIs when checking files locally.

Multiple extensions can be separated by commas. Note that if you want to check filetypes, which have multiple extensions, e.g. HTML files with both .html and .htm extensions, you need to specify both extensions explicitly.

default: md,mkd,mdx,mdown,mdwn,mkdn,mkdown,markdown,html,htm,txt

-f, --format

lychee --format <FORMAT>

Output format of final status report

default: compact

possible values: compact, detailed, json, markdown, raw

--fallback-extensions

lychee --fallback-extensions <FALLBACK_EXTENSIONS>

When checking locally, attempts to locate missing files by trying the given fallback extensions. Multiple extensions can be separated by commas. Extensions will be checked in order of appearance.

Example: --fallback-extensions html,htm,php,asp,aspx,jsp,cgi

Note: This option takes effect on file:// URIs which do not exist and on file:// URIs pointing to directories which resolve to themself (by the --index-files logic).

--files-from

lychee --files-from <PATH>

Read input filenames from the given file or stdin (if path is ’-’).

This is useful when you have a large number of inputs that would be cumbersome to specify on the command line directly.

Examples: lychee --files-from list.txt find . -name ‘*.md’ | lychee --files-from - echo ‘README.md’ | lychee --files-from -

File Format: Each line should contain one input (file path, URL, or glob pattern). Lines starting with ’#’ are treated as comments and ignored. Empty lines are also ignored.

--generate

lychee --generate <GENERATE>

Generate special output (e.g. the man page) instead of performing link checking

possible values: man

--github-token

lychee --github-token <GITHUB_TOKEN>

GitHub API token to use when checking github.com links, to avoid rate limiting

env: GITHUB_TOKEN

--glob-ignore-case

lychee --glob-ignore-case

Ignore case when expanding filesystem path glob inputs

-h, --help

lychee --help

Print help (see a summary with ‘-h’)

lychee --header <HEADER:VALUE>

Set custom header for requests

Some websites require custom headers to be passed in order to return valid responses. You can specify custom headers in the format ‘Name: Value’. For example, ‘Accept: text/html’. This is the same format that other tools like curl or wget use. Multiple headers can be specified by using the flag multiple times.

--hidden

lychee --hidden

Do not skip hidden directories and files

-i, --insecure

lychee --insecure

Proceed for server connections considered insecure (invalid TLS)

--include

lychee --include <INCLUDE>

URLs to check (supports regex). Has preference over all excludes

--include-fragments

lychee --include-fragments

Enable the checking of fragments in links

--include-mail

lychee --include-mail

Also check email addresses

--include-verbatim

lychee --include-verbatim

Find links in verbatim sections like pre- and code blocks

--include-wikilinks

lychee --include-wikilinks

Check WikiLinks in Markdown files

--index-files

lychee --index-files <INDEX_FILES>

When checking locally, resolves directory links to a separate index file. The argument is a comma-separated list of index file names to search for. Index names are relative to the link’s directory and attempted in the order given.

If --index-files is specified, then at least one index file must exist in order for a directory link to be considered valid. Additionally, the special name . can be used in the list to refer to the directory itself.

If unspecified (the default behavior), index files are disabled and directory links are considered valid as long as the directory exists on disk.

Example 1: --index-files index.html,readme.md looks for index.html or readme.md and requires that at least one exists.

Example 2: --index-files index.html,. will use index.html if it exists, but still accept the directory link regardless.

Example 3: --index-files '' will reject all directory links because there are no valid index files. This will require every link to explicitly name a file.

Note: This option only takes effect on file:// URIs which exist and point to a directory.

-m, --max-redirects

lychee --max-redirects <MAX_REDIRECTS>

Maximum number of allowed redirects

default: 5

--max-cache-age

lychee --max-cache-age <MAX_CACHE_AGE>

Discard all cached requests older than this duration

default: 1d

--max-concurrency

lychee --max-concurrency <MAX_CONCURRENCY>

Maximum number of concurrent network requests

default: 128

--max-retries

lychee --max-retries <MAX_RETRIES>

Maximum number of retries per request

default: 3

--min-tls

lychee --min-tls <MIN_TLS>

Minimum accepted TLS Version

possible values: TLSv1_0, TLSv1_1, TLSv1_2, TLSv1_3

--mode

lychee --mode <MODE>

Set the output display mode. Determines how results are presented in the terminal

default: color

possible values: plain, color, emoji, task

-n, --no-progress

lychee --no-progress

Do not show progress bar. This is recommended for non-interactive shells (e.g. for continuous integration)

--no-ignore

lychee --no-ignore

Do not skip files that would otherwise be ignored by ‘.gitignore’, ‘.ignore’, or the global ignore file

-o, --output

lychee --output <OUTPUT>

Output file of status report

--offline

lychee --offline

Only check local files and block network requests

-q, --quiet…

lychee --quiet...

Less output per occurrence (e.g. -q or -qq)

-r, --retry-wait-time

lychee --retry-wait-time <RETRY_WAIT_TIME>

Minimum wait time in seconds between retries of failed requests

default: 1

--remap

lychee --remap <REMAP>

Remap URI matching pattern to different URI

--require-https

lychee --require-https

When HTTPS is available, treat HTTP links as errors

--root-dir

lychee --root-dir <ROOT_DIR>

Root directory to use when checking absolute links in local files. This option is required if absolute links appear in local files, otherwise those links will be flagged as errors. This must be an absolute path (i.e., one beginning with /).

If specified, absolute links in local files are resolved by prefixing the given root directory to the requested absolute link. For example, with a root-dir of /root/dir, a link to /page.html would be resolved to /root/dir/page.html.

This option can be specified alongside --base-url. If both are given, an absolute link is resolved by constructing a URL from three parts: the domain name specified in --base-url, followed by the --root-dir directory path, followed by the absolute link’s own path.

-s, --scheme

lychee --scheme <SCHEME>

Only test links with the given schemes (e.g. https). Omit to check links with any other scheme. At the moment, we support http, https, file, and mailto.

--skip-missing

lychee --skip-missing

Skip missing input files (default is to error if they don’t exist)

--suggest

lychee --suggest

Suggest link replacements for broken links, using a web archive. The web archive can be specified with --archive

-t, --timeout

lychee --timeout <TIMEOUT>

Website timeout in seconds from connect to response finished

default: 20

-T, --threads

lychee --threads <THREADS>

Number of threads to utilize. Defaults to number of cores available to the system

-u, --user-agent

lychee --user-agent <USER_AGENT>

User agent

default: lychee/0.20.1

-v, --verbose…

lychee --verbose...

Set verbosity level; more output per occurrence (e.g. -v or -vv)

-V, --version

lychee --version

Print version

-X, --method

lychee --method <METHOD>

Request method

default: get

Repeating Options

Some options can be specified multiple times. This is true for:

--exclude
--exclude-path
--header
--include
--remap
--scheme

Here is an example:

lychee --exclude https://example.com --exclude https://example.org README.md

To specify multiple values in this way, the argument flag should be repeated. Otherwise, the extra values would be treated as link checking inputs.