I use up-arrow for that. My .inputrc has:

    "\e[A": history-search-backward

If you don't type anything, it acts exactly as the old up-arrow.

Or in ~/.zshrc:

    bindkey '\e[A'  history-beginning-search-backward

An important addition to that is to repeatedly hit ctrl-r to cycle through the matching commands in the history.

How do you reverse the search? <S-C-R> didn't do it for me. Either way this could be a good substitute for what I do now, tediously grepping .zsh/bash_history...

If by reverse you mean going forward instead of backwards, that should be done with Ctrl-S; it does not work in Bash though, since Ctrl-S locks the scrolling of the terminal. I believe this behavior can be overridden, through some .xinputrc settings perhaps, but I haven't still found enough motivation to look it up!

edit: ok, I've found this: http://wiki.archlinux.org/index.php/Bash#History_search

I'm pretty I learned this from reading an article on HN... anyone got a citation for me?

Perhaps my article "The Definitive Guide to Bash History?"

http://www.catonmat.net/blog/the-definitive-guide-to-bash-co...