checklink1

Check the validity of links in an html or xhtml document

Usage

checklink [options] uri ...

Overview

This manual page documents briefly the checklink command, a.k.a. the W3C® Link Checker.

checklink is a program that reads an HTML or XHTML document, extracts a list of anchors and lists and checks that no anchor is defined twice and that all the links are dereferenceable, including the fragments. It warns about HTTP redirects, including directory redirects, and can check recursively a part of a web site.

The program can be used either as a command line tool or as a CGI script.

Options

This program follow the usual GNU command line syntax, with long options starting with two dashes (`-'). A summary of options is included below.

-?, -h, --help: Show summary of options.

-V, --version: Output version information.

-s, --summary: Show result summary only.

-b, --broken: Show only the broken links, not the redirects.

-e, --directory: Hide directory redirects - e.g. <http://www.w3.org/TR> -> <http://www.w3.org/TR/>.

-r, --recursive: Check the documents linked from the first one.

-D, --depth n: Check the documents linked from the first one to depth n (implies --recursive).

-l, --location uri: Scope of the documents checked in recursive mode. By default, for <http://www.w3.org/TR/html4/Overview.html> for example, it would be <http://www.w3.org/TR/html4/>.

--exclude-docs regexp: In recursive mode, do not check links in documents whose URIs match regexp.

-L, --languages accept-language: The "Accept-Language" HTTP header to send. In command line mode, this header is not sent by default. The special value "auto" causes a value to be detected from the "LANG" environment variable, and sent if found. In CGI mode, the default is to send the value received from the client as is.

-q, --quiet: No output if no errors are found.

-v, --verbose: Verbose mode.

-i, --indicator: Show progress while parsing.

-u, --user username: Specify a username for authentication.

-p, --password password: Specify a password for authentication.

--hide-same-realm: Hide 401's that are in the same realm as the document checked.

-S, --sleep secs: Sleep the specified number of seconds between requests to each server. Defaults to 1 second, which is also the minimum allowed.

-t, --timeout secs: Timeout for requests, in seconds.

-d, --domain domain: Perl regular expression describing the domain to which the authentication information (if present) will be sent. The default value can be specified in the configuration file. See the "Trusted" entry in the configuration file description below for more information.

--masquerade "local remote"

Masquerade local dir as a remote URI. For example, the following results in /my/local/dir/ being "mapped" to http://some/remote/uri/

  --masquerade "/my/local/dir http://some/remote/uri/"

As of revision 3.6.2.19 of checklink, --masquerade takes a single argument consisting of two URIs, separated by whitespace. One usual way of providing a value with embedded whitespace is to enclose it in quotes.

-y, --proxy proxy: Specify an HTTP proxy server.

-H, --html: HTML output.

Files

/etc/w3c/checklink.conf

The main configuration file. You can use the W3C_CHECKLINK_CFG environment variable to override the default location.

"Trusted" specifies a regular expression for matching trusted domains (ie. domains where HTTP basic authentication, if any, will be sent). The regular expression will be matched case insensitively against host names. The default behavior (when unset, that is) is to send the authentication information only to the host which requests it; usually you don't want to change this. For example, the following configures only the w3.org domain as trusted:

    Trusted = \.w3\.org$

"Allow_Private_IPs" is a boolean flag indicating whether checking links on non-public IP addresses is allowed. The default is true in command line mode and false when run as a CGI script. For example, to disallow checking non-public IP addresses, regardless of the mode, use:

   Allow_Private_IPs = 0

"Markup_Validator_URI" and "CSS_Validator_URI" are formatted URIs to the respective validators. The %s in these will be replaced with the full "URI encoded" URI to the document being checked, and shown in the link checker results view in the online/CGI version. The defaults are:

   Markup_Validator_URI =
     http://validator.w3.org/check?uri=%s
   CSS_Validator_URI =
     http://jigsaw.w3.org/css-validator/validator?uri=%s

"Doc_URI" and "Style_URI" are URIs used for linking to the documentation and style sheet from the dynamically generated content of the link checker. The defaults are:

   Doc_URI = http://validator.w3.org/docs/checklink.html
   Style_URI = http://validator.w3.org/docs/linkchecker.css

Environment

checklink uses the libwww-perl library which has a number of environment variables affecting its behaviour. See "SEE ALSO" for some pointers.

W3C_CHECKLINK_CFG: If set, overrides the path to the configuration file.