sshelper 我很喜欢的应用，用途是在手机上开启 ssh 服务等，可局域网内设备间交互文件或粘贴板信息等。
详见 应用主页

这里引用下介绍

• SSHelper is an advanced, multi-protocol, secure server for the Android platform.
• SSHelper requires Android version 5.0, API 21, or newer.
• SSHelper works just fine with a normal, unrooted Android device — i.e. your device.
• SSHelper works as an application and as a service. As a service it runs in the background, providing secure communications protocols without requiring user attention.
• SSHelper supports interactive Secure Shell (hereafter SSH) sessions and various kinds of transfers including scp, sftp, and rsync, on all common platforms:
  On Windows, SSHelper works with WinSCP, PuTTY and similar programs.
  On Linux, apart from normal SSH shell session activities, SSHelper can be used directly with file browsers for seamless filesystem browsing and transfers by specifying the "sftp:" protocol.
  On the Mac, SSHelper works with Cyberduck and similar programs.
• SSHelper announces its services on your local network by way of Zeroconf/Bonjour, a simple and efficient way to configure, and communicate within, a network.
• SSHelper hosts an activity log Web server that gives a remote view of the activity log — useful for administration and development.
• SSHelper also hosts a clipboard access Web server that provides read/write access to the Android clipboard from any browser on the local network.
• SSHelper is free, open-source and there are no ads. It's licensed under the GPL and the source is freely available.