NAME

       checklink - check the validity of links in an HTML or XHTML document

SYNOPSIS

       checklink  [ options ] uri ...

DESCRIPTION

       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 links 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, --dir-redirects
            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 (implies --recursive).  Can be specified multiple
            times in order to specify multiple recursion bases.  If the URI of a candidate
            document is downwards relative to any of the bases, it is considered to be within the
            scope.  If not specified, the default is the base URI of the initial document, for
            example for <http://www.w3.org/TR/html4/Overview.html> it would be
            <http://www.w3.org/TR/html4/>.

       -X, --exclude regexp
            Do not check links whose full, canonical URIs match regexp.  Note that this option
            limits recursion the same way as --exclude-docs with the same regular expression
            would.

       --exclude-docs regexp
            In recursive mode, do not check links in documents whose full, canonical URIs match
            regexp.  This option may be specified multiple times.

       --suppress-redirect URI->URI
            Do not report a redirect from the first to the second URI.  The "->" is literal text.
            This option may be specified multiple times.  Whitespace may be used instead of "->"
            to separate the URIs.

       --suppress-redirect-prefix URI->URI
            Do not report a redirect from a child of the first URI to the same child of the
            second URI.  The \"->\" is literal text.  This option may be specified multiple
            times.  Whitespace may be used instead of "->" to separate the URIs.

       --suppress-temp-redirects
            Do not report warnings about temporary redirects.

       --suppress-broken CODE:URI
            Do not report a broken link with the given CODE.  CODE is the HTTP response, or -1
            for robots exclusion.  The ":" is literal text.  This option may be specified
            multiple times.  Whitespace may be used instead of ":" to separate the CODE and the
            URI.

       --suppress-fragment URI
            Do not report the given broken fragment URI.  A fragment URI contains "#".  This
            option may be specified multiple times.

       -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.

       -c, --cookies cookie-file
            Use cookies, load/save them in cookie-file.  The special value "tmp" causes non-
            persistent use of cookies, i.e. they are used but only stored in memory for the
            duration of this link checker run.

       -R, --no-referer
            Do not send the "Referer" HTTP header.

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

       -v, --verbose
            Verbose mode.

       -i, --indicator
            Show progress while parsing as percentage of lines processed.  No indicator is shown
            for documents containing no linefeeds.

       -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.  The default is 30.

       -C, --connection-cache number
            Maximum number of cached connections.  Using this option overrides the
            "Connection_Cache_Size" configuration file parameter, see its documentation below for
            the default value and more information.

       -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 "real-prefix surrogate-prefix"
            Perform a simple string substitution: URIs which begin with the string "real-prefix"
            are rewritten using the "surrogate-prefix" before being dereferenced.  Useful for
            making a local directory masquerade as a remote one. For example:

              --masquerade "http://example.com/x/y/z/ file:///my/local/dir/"

            If the document being checked contains a link to http://example.com/x/y/z/foo.html,
            then the local file system will be checked for file:///my/local/dir/foo.html.

            --masquerade takes a single argument consisting of two URIs, separated by whitespace.
            The quote marks are not part of the argument, but one usual way of providing a value
            with embedded whitespace is to enclose it in quotes.

       -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

            "Forbidden_Protocols" is a comma separated list of additional protocols/URI schemes
            that the link checker is not allowed to use.  The "javascript" and "mailto" schemes
            are always forbidden, and so is the "file" scheme when running as a CGI script.

               Forbidden_Protocols = javascript,mailto

            "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" is a URI used for linking to the documentation, and CSS and JavaScript
            files in the dynamically generated content of the link checker.  The default is:

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

            "Connection_Cache_Size" is an integer denoting the maximum number of connections the
            link checker will keep open at any given time.  The default is:

               Connection_Cache_Size = 2

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.

SEE ALSO

       The documentation for this program is available on the web at
       <http://validator.w3.org/docs/checklink.html>.

       LWP, Net::FTP, Net::NNTP, Net::IP, perlre.

AUTHOR

       This program was originally written by Hugo Haas <hugo@w3.org>, based on Renaud Bruyeron's
       checklink.pl.  It has been enhanced by Ville Skyttä and many other volunteers since.  Use
       the <www-validator@w3.org> mailing list for feedback, and see
       <http://validator.w3.org/docs/checklink.html#csb> for more information.

       This manual page was originally written by Frédéric Schütz <schutz@mathgen.ch> for the
       Debian GNU/Linux system (but may be used by others).

COPYRIGHT

       This program is licensed under the W3C® Software License,
       <http://www.w3.org/Consortium/Legal/copyright-software>.