Interactive editor
cf. my (slightly outdated) blog post: Integrating vim and irb and vimcasts #20: Running Vim within IRB.
Usage
$ gem install interactive_editor
Put the following in your .irbrc:
require 'rubygems'
require 'interactive_editor'
Then, from within irb:
$ irb
> vi # (use vi w/ temp file)
> vi 'filename.rb' # (open filename.rb in vi)
> ed # (use EDITOR env variable)
> [emacs|vim|mvim|nano|mate] # (other editors)
To try it out without installing the gem:
$ git clone git://github.com/jberkel/interactive_editor.git
$ cd interactive_editor
$ rake console
Credits
Giles Bowkett, Greg Brown, and several audience members from Giles' Ruby East presentation: Use vi or any text editor from within IRB.