Package: rubygem-json

"rubygem-json" package binaries on CentOS:

/usr/bin/prettify_json.rb /usr/lib/ruby/gems/1.8/gems/json-1.4.6/bin/edit_json.rb /usr/lib/ruby/gems/1.8/gems/json-1.4.6/bin/prettify_json.rb

You may install this package on CentOS with yum install rubygem-json