Convert Ruby 1.8 to 1.9 Hash Syntax

In Vim, for an entire file:

:%s/:\([^ ]*\)\(\s*\)=>/\1:/g

In the shell, for an entire project:

perl -pi -e 's/(?<![:]):([\w\d_]+)(\s*)=>/\1:/g' **/*.rb

Now, instead of those old-school hashes like this:

get "/", :agent => MOBILE_BROWSERS do

You’ll have new-school hashes like this:

get "/", agent: MOBILE_BROWSERS do