Um, that sounds like something more suited to a simple sed or awk script; something like this:
ls | sed -r -n [line noise]
Or mmv.
In any case I have decided to have a bit of fun with geany and managed to bash this together in the last hour or two.
http://mavis.anu.edu.au/geany/shiftcolumn-0.1.tar.gz
There seems to be a change in the API between 0.15 and 0.16 with p_document and document.h. For now the plugin doesn't do much except put the current selected text when you press <Ctrl>9 I spent time trying to figure out the plugin API for keybindings and the likes instead.
Can one of the Geany Devs please let me know if I am on the right track? From here I think it is just a bit more scintilla fiddling (get position, rotate text) and it should all work. (plus a bit of bounds checking).
thanks
-- Andrew Janke (a.janke@gmail.com || http://a.janke.googlepages.com/) Canberra->Australia +61 (402) 700 883