lucy24 - 1:35 am on Dec 7, 2012 (gmt 0)
Yup. But watch out: I'd no sooner blocked UAs containing multi-spaces than I ran into a perfectly legitimate human UA that really did have two spaces. They're not all plainclothes bingbots, darn it.
SetEnvIf User-Agent "; " keep_out
I assume that one begin life as a double space before the Forums crunched it. You can protect multi-spaces in posts by using nonbreaking spaces, as in html-- but only as long as everyone reading the thread uses the same file encoding. Otherwise some folks will see (A-circumflex with following nbsp) instead.
Now watch as this gets recursive. Only the first 16 Latin-1 characters have this feature.
Oh yes and: mod_setenvif uses Regular Expressions, so you can do package deals like " [);:]".