searching for pages explaining codes

Question

Google does not allow searching for !

!-f becomes -f

What search engines find pages with !-f?

Answer 1

There are other characters too that do not return any result (eg @, #, $ etc.). Infact the only two characters that are honoured are '&' and '_'
Check this post.

Answer 2

It seems to work if you put it in quotes, like "!-f", did you try that? from http://knol.google.com/k/barry-welford/the-humble-exclamation-mark/3fhotx4fqh463/2# :

Google doesn’t recognize special characters such as exclamation points, question marks, or the @ sign. These types of characters are so common that including them in a search would greatly slow the delivery of the search results.