set system envs by ruby shell

Rakefile

# encoding: utf-8

require 'rubygems'

configs = {
    'envs' =>
      {'RUBY_HOME' => 'ruby_home_path', 'JRUBY_HOME' => 'jruby_home_path', 'JAVA_HOME' => 'java_home_path'},
    'add_path_env'  =>
      {'RUBY_HOME' => 'bin', 'JRUBY_HOME' => 'bin', 'JAVA_HOME' => 'bin'}
}
host_os = RbConfig::CONFIG['host_os']

if host_os =~ /mswin|msys|mingw|cygwin|bccwin|wince|emc/
  reg_path = "HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment"

  desc "Set envs and add path"
  task :all => ['windows:add_path', 'windows:set_evn']

  desc "Set envs"
  task :set_evn do
    configs['envs'].each do |key, value|
      system("reg add \"#{reg_path}\" /v \"#{key}\" /d \"#{value}\" /f > nul")
    end
    puts "Set envs over."
  end

  desc "Add path"
  task :add_path do
    path = ENV["path"]
    configs['add_path_env'].keys.reverse.each do |key|
      path = "%#{key}%\\#{configs['add_path_env'][key]};" + path
    end
    system("reg add \"#{reg_path}\" /v \"test_path\" /d \"#{path}\" /f > nul")
    puts "Add path over."
  end
end

if host_os =~ /linux|darwin|mac os/
  shell_file = ENV["SHELL"].split("/")[-1] == "zsh" ? "~/.zshrc" : "~/.bashrc"

  desc "Set envs and add path"
  task :all => ['linux:set_evn', 'linux:add_path']

  desc "Set envs"
  task :set_evn do
    File.open(shell_file, 'a') do |file|
      configs['envs'].each do |key, value|
        file.puts "#{key}=#{value}"
      end
    end
    puts "Set envs over."
  end

  desc "Add path"
  task :add_path do
    path = "$PATH"
    File.open(shell_file, 'a') do |file|
      configs['add_path_env'].keys.reverse.each do |key|
        path = "$#{key}/#{configs['add_path_env'][key]}:" + path
      end
      file.puts path
    end
    puts "Add path over."
  end
end