A command-line application in Android is written in the same way, regardless of the platform. Figure 5 shows an example of a simple “Hello World” application.

Linux CLI Launcher lets you turn your Android smartphone into an operable Linux command line so you can operate your device with native commands.

Windows: ADB and fastboot are two immensely powerful tools. If you're new to using them, or just want to simplify the process a bit, Universal ADB Helper can make certain tasks a snap.

While you could install multiple apps to accomplish automation tasks, there are plenty of command line tools that can abstract away complex tasks, whichever operating system you're using at the time.