Emacs. This comes first into my mind when I hear the word "programming tool". Emacs' default configuration is horrible. It took me many months to get used to i

Emacs. This comes first into my mind when I hear the word "programming tool". Emacs' default configuration is horrible. It took me many months to get used to it and to realize a perfectly convenient configuration. But since I did that 25 years ago I have stuck with it to this day. Emacs' killer feature is its almost unlimited programmability. org-mode is just one awesome example. There are several other good editors (vim, sublime, atom etc.) but none of them comes close to the power of Emacs.