こんなので.ssh/config切り替えると便利な気がする

gistfile1.rb

#!/usr/bin/env ruby

require 'thor'

class SSHEnv < Thor
  SSH_DIR = "~/.ssh"

  desc 'use PRESET', 'Switch SSH config preset to PRESET'
  method_option :dry, :type => :boolean, :aliases => '-d'
  def use(name="default")
    @dry = options.dry
    sh "rm #{config}" if File.exists? File.expand_path(config)
    sh "touch #{config_preset name}" unless File.exists? File.expand_path("#{config_preset name}")
    sh "ln -s #{config_preset name} #{config}"
  end

  desc 'preset', 'Show current preset'
  def preset
    puts current_preset_name
  end

  desc 'presets', 'List presets'
  def presets
    current = current_preset_name
    preset_names.each do |line|
      puts "#{current == line ? '* ' : '  '}#{line}"
    end
  end

  no_tasks do
    def method_missing(method_name)
      use method_name
    end

    def exists?(file)
      File.exists? File.expand_path(file)
    end

    def sh(cmd)
      if @dry
        puts cmd
      else
        system cmd
      end
    end

    def config
      "#{SSH_DIR}/config"
    end

    def config_preset(name)
      "#{SSH_DIR}/config.#{name}"
    end

    def current_preset_name
      return nil unless File.exists? File.expand_path(config)
      `ls -l #{config}`.gsub(/.*\.([^.]+)$/, '\1')
    end

    def preset_names
      `ls -l #{config_preset '*'}`.gsub(/.*\/config\.([^.]+)$/, '\1').lines.to_a
    end
  end
end

SSHEnv.start