I have a workflow where I use grep and other tools in a shell for searching in different projects even though my main editor is emacs. I usually work on bug fixing and minor development of source code that is often unknown to me so searching the code is important. The langages I mostly work in are php, ruby, java, perl and sometimes python.
Is there some common IDE extension in emacs that would enable me to have functionality like “goto definition” from multiple files that span all these languages? Are there some other modules that could be useful, either code browsing or indexed search?
If you want to work with lots of different languages, ctags is pretty flexible. See the EmacsWiki for instructions on integration of ctags.