pre-commit hook calling Rubocop to check staged ruby style

pre-commit

#!/bin/sh
# Commit this file to your project somewhere, then instruct teammates who wants to opt in to symlink to run the hook:
#   ln -sf ../../pre-commit .git/hooks/pre-commit


# To capture user input
exec < /dev/tty

./style_check # or wherever you keep the style_check script

if [ $? != 0 ]; then
  while true; do
    echo ""
    read -p "Do you want to fix the above offences before committing, and be an awesome dev? (Y/n)" yn
    case $yn in
      [Yy]* ) exit 1;;
      [Nn]* ) break;;
      * ) echo "Please answer yes or no.";;
    esac
  done
fi

style_check

#!/usr/bin/env ruby
#
# Checks style on staged ruby files
# Commit this to your project root
#

require 'rubocop'

ADDED_OR_MODIFIED = /A|AM|^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