OpenGrok is a source code search and cross reference engine. It helps programmers to search, cross-reference and navigate source code trees.It can understand various program file formats and version control histories like Monotone, SCCS, RCS, CVS, Subversion, Mercurial, Git, Clearcase, Perforce and Bazaar.The name comes from the term grok, a jargon term used in computing to mean "profoundly understand". The term grok originated in a science fiction novel by Robert A.