W3C Broken Link Checker

"The World Wide Web Consortium (W3C® ) was created in October 1994, and is the chief standards body for HTML. When a new HTML specification (which defines how Web pages should be displayed by Web browsers) is approved by W3C, it is assigned a unique document type definition (DTD) and is called a DOCTYPE. To ensure your Webpage complies with HTML standards, you need to validate (test) each page according to the specific rules that apply to the HTML standard used to create it."

http://www.yellowpipe.com/yis/tools/link_checker/w3c.php

Automating UNIX system administration with Perl

"UNIX system administration, always a thorny problem, is easier with the right tools. In this installment, Teodor presents ideas on the use of Perl to streamline and foolproof system administration. The system configuration engine, cfengine, is an extremely important tool in this context."

http://www.ibm.com/developerworks/linux/library/l-punix.html