Simple script to manage different database.yml files in a rails development environment

changedb

#!/home/lucas/.rbenv/shims/ruby
# Use an appropriate file path for your ruby interpreter

require 'fileutils'

class ChangeDB

  def initialize dir='config/.changedb', db_yml='config/database.yml'
    @dir = dir
    @db_yml = db_yml
    @current_file = "#{@dir}/current"

    # create if doesnt exist
    Dir.mkdir(@dir) if !File.directory?(@dir)

    @files = Dir.glob("#{@dir}/*").map{|filename| filename.split('/')[-1]}
    @files -= ['current']
  end

  def classy_exit
    puts "Run it like this:"
    puts "    $ changedb list"
    puts "    $ changedb use [dbname]"
    puts "    $ changedb save [dbname]"
    exit 0
  end

  def current
    IO.read(@current_file).chomp
  end

  def set_current filename
    File.open(@current_file, 'w') {|f| f.puts filename }
  end

  def list
    puts @files.map{ |file| "  #{current == file ? '*' : ' '} #{file}" }
  end

  def use filename
    FileUtils.cp "#{@dir}/#{filename}", @db_yml
    set_current filename
  end

  def save filename
    FileUtils.cp @db_yml, "#{@dir}/#{filename}"
  end
end

# Do real stuff
if __FILE__ == $0
  changedb = ChangeDB.new
  changedb.classy_exit if ARGV.empty?

  case ARGV[0]
    when 'list' then
      changedb.list
    when 'use' then
      changedb.use ARGV[1]
    when 'save'
      changedb.save ARGV[1]
    else
      changedb.classy_exit
  end
end