Provided by: w3c-linkchecker_4.81-6_all
checklink - check the validity of links in an HTML or XHTML document
checklink [ options ] uri ...
This manual page documents briefly the checklink command, a.k.a. the
W3CX 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
This program follow the usual GNU command line syntax, with long
options starting with two dashes (`-'). A summary of options is
-?, -h, --help
Show summary of options.
Output version information.
Show result summary only.
Show only the broken links, not the redirects.
Hide directory redirects - e.g. <http://www.w3.org/TR> ->
Check the documents linked from the first one.
-D, --depth n
Check the documents linked from the first one to depth n (implies
-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
-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.
In recursive mode, do not check links in documents whose full,
canonical URIs match regexp. This option may be specified
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
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.
Do not report warnings about temporary redirects.
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.
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
only stored in memory for the duration of this link checker run.
Do not send the "Referer" HTTP header.
No output if no errors are found. Implies --summary.
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 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
--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.
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 = \.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.
is the "file" scheme when running as a CGI script.
"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:
"Doc_URI" is a URI used for linking to the documentation, and CSS
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
checklink uses the libwww-perl library which has a number of
environment variables affecting its behaviour. See "SEE ALSO" for some
If set, overrides the path to the configuration file.
The documentation for this program is available on the web at
LWP, Net::FTP, Net::NNTP, Net::IP, perlre.
This program was originally written by Hugo Haas <firstname.lastname@example.org>, based
on Renaud Bruyeron's checklink.pl. It has been enhanced by Ville
Skyttae and many other volunteers since. Use the
<email@example.com> mailing list for feedback, and see
<http://validator.w3.org/docs/checklink.html#csb> for more information.
This manual page was originally written by Frederic Schuetz
<firstname.lastname@example.org> for the Debian GNU/Linux system (but may be used by
This program is licensed under the W3CX Software License,