Vim has this nice feature where you can edit directories as well as files. Just say: vi dir Now you're looking at a directory listing, and you can move down to an entry and press Enter to go there. When you're inside a file, you can go back up with: :e .. You can also use wildcards and tab completion. I suppose for finding routines you can use ctags, though I haven't bothered with that in quite a while.
That didn't work for me with nvi or vim, it just says, "/usr is a directory". Does it require an extension? (I'm assuming your 'vi' is a symlink to 'vim', which is not always the case.) Similarly, Emacs has dired, and in some extensions you can edit the file metadata in place and hit save to rename files, chmod, etc.
(netrw has always been enabled-by-default for me, but I've spent most of my time on desktop-oriented Linux distros.)