reallyCleanXcode.rb

# run with 
# ruby reallyCleanXcode.rb
derivedDataFolder = Dir.glob(Dir.home + "/Library/Developer/Xcode/DerivedData/*")
moduleCache = Dir.glob("/var/folders/**/com.apple.DeveloperTools*")
FileUtils.rm_rf derivedDataFolder + moduleCache

sh-3.2# ruby reallyCleanXcode.rb 
reallyCleanXcode.rb:4: syntax error, unexpected **arg
moduleCache = Dir.glob("/var/folders/**/com.apple.DeveloperTools*”)
                                       ^
reallyCleanXcode.rb:4: unterminated regexp meets end of file

... :/
What can I do ?

Your quotes seem to be incorrect. The second one seems to be a ” instead of a ".

suggesting this changes and additional chmod +x filename.rb for ./filename.rb usage

#!/usr/bin/env ruby
require 'fileutils'
derivedDataFolder = Dir.glob(Dir.home + "/Library/Developer/Xcode/DerivedData/*")
moduleCache = Dir.glob("/var/folders/**/com.apple.DeveloperTools*")
FileUtils.rm_rf derivedDataFolder + moduleCache