check websites and HTML documents for broken links

 Provides a command line program and web interface to check links
 of websites and HTML documents.
 Features:
  * recursive checking
  * multithreaded
  * output in colored or normal text, HTML, SQL, CSV, XML or a sitemap
    graph in different formats
  * HTTP/1.1, HTTPS, FTP, mailto:, news:, nntp:, Telnet and local file
    links support
  * restrict link checking with regular expression filters for URLs
  * proxy support
  * username/password authorization for HTTP, FTP and Telnet
  * robots.txt exclusion protocol support
  * Cookie support
  * i18n support
  * HTML and CSS syntax check
  * Antivirus check