pre-commit_rubocop.rb

#!/usr/bin/env ruby
 
require 'english'
require 'rubocop'
 
ADDED_OR_MODIFIED = /A|AM|M|^M/.freeze
 
changed_files = `git status --porcelain`.split(/\n/).
    select { |file_name_with_status|
      file_name_with_status =~ ADDED_OR_MODIFIED
    }.
    map { |file_name_with_status|
      file_name_with_status.split(' ')[1]
    }.
    select { |file_name|
      File.extname(file_name) == '.rb'
    }.join(' ')
 
system("rubocop #{changed_files}") unless changed_files.empty?
 
exit $CHILD_STATUS.to_s[-1].to_i