Use the following: lsof -i :4000 To kill the process use kill -9 PID

To add a folder to your PATH, add the following to your bash config: export PATH="$PATH:/foo/bar" To check what is on your path, run: echo $PATH

weekly_meters.each do |week, meters| puts "#{week}: #{meters}" end

# create hash my_dict = { "apples" => 3, "pears" => 2 } # check if a key exists puts my_dict.has_key?("apples") # true puts my_dict.has_key?("oranges") # false Sources ruby docs