How do I 301 redirect a bad incoming link such as www.site.com / or www.site.com/ <space after it

I hav开发者_如何学编程e bad incoming links which webmaster tools shows, how do I fix the issue, I've tried all kinds of different 301 rewrites and redirects, nothing seems to work.

You could redirect 'too short' URLs like site.com/%20 (waste space) or site.com/. (waste dot) to the main page:

RewriteEngine on
RewriteRule ^.{1,3}$ / [R=301,L]