I believe I have found a bug that exists in readline 6.3.6. I've downgraded to 6.2.4 and everything works fine. The basic issue is after a window resize, input overwraps itself. I have verified this is the case in both iTerm2 and Terminal, on OS X 10.9.4. A video of the problem is here: https://www.youtube.com/watch?v=A9tvPhehB-0