```ruby
module VagrantPlugins
  module GuestUbuntu
    module Cap
      class ChangeHostName < VagrantPlugins::GuestDebian::Cap::ChangeHostName
        def self.change_host_name(machine, name)
          super
        end

        def update_etc_hostname
          return super unless systemd?
          sudo("hostnamectl set-hostname '#{short_hostname}'")
        end

        def refresh_hostname_service
          if hardy?
            # hostname.sh returns 1, so use `true` to get a 0 exitcode
            sudo("/etc/init.d/hostname.sh start; true")
          elsif systemd?
            # Service runs via hostnamectl
          else
            sudo("service hostname start")
          end
        end

        def hardy?
          os_version("hardy")
        end

        def renew_dhcp
          sudo("ifdown -a; ifup -a; ifup -a --allow=hotplug")
        end

      private

        def init_package
          machine.communicate.execute('cat /proc/1/comm') do |type, data|
            return data.chomp if type == :stdout
          end
        end

        def os_version(name)
          machine.communicate.test("[ `lsb_release -c -s` = #{name} ]")
        end

        def systemd?
          init_package == 'systemd'
        end
      end
    end
  end
end
```

Change host name in one command
user
```ruby
module VagrantPlugins
  module GuestUbuntu
    module Cap
      class ChangeHostName
        def self.change_host_name(machine, name)
          comm = machine.communicate

          if !comm.test("hostname -f | grep -w '#{name}'")
            basename = name.split(".", 2)[0]
            comm.sudo <<-EOH.gsub(/^ {14}/, '')
              # Set the hostname
              echo '#{name}' > /etc/hostname
              hostname -F /etc/hostname

              if command -v hostnamectl; then
                hostnamectl set-hostname '#{name}'
              fi

              # Remove comments and blank lines from /etc/hosts
              sed -i'' -e 's/#.*$//' -e '/^$/d' /etc/hosts

              # Prepend ourselves to /etc/hosts
              grep -w '#{name}' /etc/hosts || {
                sed -i'' '1i 127.0.0.1\\t#{name}\\t#{basename}' /etc/hosts
              }

              # Update mailname
              echo '#{name}' > /etc/mailname

              # Restart networking and force new DHCP
              if [ test -f /etc/init.d/hostname ]; then
                /etc/init.d/hostname start || true
              fi

              if [ test -f /etc/init.d/hostname.sh ]; then
                /etc/init.d/hostname.sh start || true
              fi

              if [ test -f /etc/init.d/networking ]; then
                /etc/init.d/networking force-reload
              fi

              if [ test -f /etc/init.d/network-manager ]; then
                /etc/init.d/network-manager force-reload
              fi
            EOH
          end
        end
      end
    end
  end
end
```
assistant