Possible Duplicate:
What IDE / Editor do you use for Ruby on Linux?
what do you consider the best ide for developing ruby and rails on linux? thanks.
Possible Duplicate:
What IDE / Editor do you use for Ruby on Linux?
what do you consider the best ide for developing ruby and rails on linux? thanks.
I know it's not for Linux, but I'd say Textmate anyway, it is reason enough to get a Mac :)
To be more serious, I would recommend vi, or more precisely Vim. It's more lightweight than anything else and still manage to do the job right, so for Linux I don't think there are any other options and for Ubuntu (and probably Debian and the rest of them) there is even a package, vim-rails, that contain a lot of scripts to ease up the development.
I don't think you need an IDE. Rails isn't that complicated, all it takes is a text editor and a terminal.
So, I recommend that you use a text editor such as emacs, vim, gedit or whatever. The KDE/Gnome terminals are more than good enough. You might want to look into using ZSH instead of bash.