pasteRTFasMarkdown.sh

#!/bin/sh

# Convert RTF contents of clipboard to HTML

osascript -e 'the clipboard as «class RTF »' | \
perl -ne 'print chr foreach unpack("C*",pack("H*",substr($_,11,-3)))' | \
textutil -format rtf -convert html -stdin -stdout | \
pandoc -f html -t markdown | \
pbcopy

# Paste contents of the clipboard into the current application

osascript <<EOF

(* 

First we need to get the name of the current application. Trick
borrowed from http://vanderbrew.com/blog/2010/02/15/get-current-application-with-applescript/

*)

on GetCurrentApp()
	tell application "System Events"
		set _app to item 1 of (every process whose frontmost is true)
		return name of _app
	end tell
end GetCurrentApp
set _app to GetCurrentApp()

(* 

Now we need to paste into the current app. I don't know any way to do this
aside from using GUI scripting (ugh).

*)

tell application _app to activate

tell application "System Events"
	tell process _app
		tell menu bar 1
			tell menu bar item "Edit"
				tell menu "Edit"
					click menu item "Paste"
				end tell
			end tell
		end tell		
	end tell
end tell
EOF

This is a script that converts RTF text on the clipboard to markdown, and then pastes that markdown into the currently active window. For reasons I don't understand, the pasting part doesn't work with Firefox. I run the script using a Quicksilver trigger. If you run it from the command line, it will attempt to paste the markdown into the terminal window, which is probably not what you want.