window里的wsl，root密码

window wsl相关配置
1.查看当前系统安装的linux:  
  PS C:> wslconfig /l
  适用于 Linux 的 Windows 子系统:
  Ubuntu (默认)
2.查看ubuntu的配置帮助
  PS C:> ubuntu /h
  Launches or configures a Linux distribution.
  Usage:
      <no args>
          Launches the user's default shell in the user's home directory.
      install [--root]
          Install the distribuiton and do not launch the shell when complete.
            --root
                Do not create a user account and leave the default user set to root.
      run <command line>
          Run the provided command line in the current working directory. If no
          command line is provided, the default shell is launched.
      config [setting [value]]
          Configure settings for this distribution.
          Settings:
            --default-user <username>
                Sets the default user to <username>. This must be an existing user.
      help
          Print usage information.
3.注：当wsl里的root密码忘了时，以管理员身份打开cmd或powershell：
  PS C:> ubuntu config --default-user root
  PS C:> wsl
  root@universe:/mnt/c# passwd
  Enter new UNIX password: