Zombie Killer
In YaST we have tons of Ruby code which is ugly, because it was translated from a legacy language, striving for bug-compatibility.
Zombie Killer analyzes the code for situations where it is safe to replace the ugly variants with nice ones.
See the runnable specification for details.
Installation
Source: clone the git repository.
Dependencies: run bundle.
(On openSUSE, most dependencies are packaged as rubygem-*.rpm except unparser)
Usage
zk [FILES...] works in place, so it is best to use in a Git checkout.
By default it finds all *.rb files under the current directory.