Ack is designed as an alternative for 99% of the uses of grep. ack is intelligent about the files it searches. It knows about certain file types, based on both the extension on the file and, in some cases, the contents of the file.
cgvg is a pair of Perl scripts («cg» and «vg») which are meant to assist a programmer in doing command-line source browsing.
codequery is a code-understanding, code-browsing or code-search tool. This is a tool to index, then query or search C, C++, Java, Python, Ruby, Go and Javascript source code. It builds upon the databases of cscope and ctags, and provides a nice GUI tool.
moap is a Swiss army knife for project maintainers and developers. It aims to help in keeping you in the flow of maintaining, developing, and releasing. It automates whatever tasks can be automated. It allows you to parse DOAP files and submit releases, send release mails, create iCal files and RSS feeds, maintain version control ignore lists, check in based on the latest ChangeLog entry, and more.
universal-ctags generates an index (or “tag”) file for a variety of language objects found in source file(s). This tag file allows these items to be quickly and easily located by a text editor or other utilities (client tools). A tag signifies a language object for which an index entry is available (or, alternatively, the index entry created for that object).