On Solaris 2.x platforms, the SGML validator is nsgmls, and on SunOS 4.1 platforms, html-check is used. On both platforms, weblint is the lint program. Additional information on weblint and nsgmls is available from the respective man pages. If you have links to external documents, they also are often moved or disappear, leaving you with broken links. Note that lynx must be in your path for this to work correctly.
More information is available in the checker manual .