I modified my .bash_profile on my Mac (now running Tiger) to get a different command prompt. Before I did that, I used to be able to use the up arrow key to cycle through previously issued commands. Now, though, I get a weird mix of characters -- it kind of overwrites the prompt with a partial mix of the previous command, making it unreadable. It's very odd and I've clearly done something wrong. The command is actually all there -- if I hit enter, it works, even though I can't clear read it.
export PS1="\[\e[0;36m \w $\[\e[0m\] "