"validate", the Offline HTMLHelp.com Validator, checks the syntax of HTML
documents using an SGML parser and reports any errors.  XHTML documents
may also be validated using an XML parser.

Usage: validate [OPTION] [FILE...]
        
The program's options are as follows:
  -w, --warn            include warnings
  --xml                 indicate that the documents to be validated are XML
                        documents.  Known document types, such as HTML 4.01 and
                        XHTML 1.0, are automatically handled by "validate".
                        For unknown document types, "validate" will assume
                        XHTML/XML if this option is specified and HTML/SGML
                        otherwise.
  --charset=ENCODING    force ENCODING to be used as the character encoding
                        when validating HTML/SGML documents.  This option is
                        ignored when validating XHTML/XML documents, which
                        are assumed to use XML rules for specifying the
                        character encoding.  The following encodings
                        (case-insensitive) are supported: "utf-8",
                        "iso-10646-ucs-2", "euc-jp", "euc-kr", "gb2312",
                        "shift_jis", "big5", and "iso-8859-n" where n is
                        between 1 and 9 inclusive.
  --verbose             turn on verbose output messages
  --[no]emacs           (don't) use an output format intended for parsing
                        by (X)Emacs, autodetected
  -h, --help            display this help and exit
  -v, --version         output version information and exit

Any number of files may be specified after the options.  With no FILE,
standard input is read.

Files can also be URIs if you have the URI and libwww-perl packages
installed.  Support for different URI schemes is also determined by these
packages.  Proxy settings are loaded from environment variables for
each scheme--e.g., http_proxy=http://localhost:3128.

"validate" is written by Liam Quinn <liam@htmlhelp.com> and is based on the
WDG HTML Validator, an online validation service available at
<http://www.htmlhelp.com/tools/validator/>.