Assuming you have a rooted android device with su and busybox installed, botbrew counts too, read the following and play with the command line.
In the follow up we will write android shell commands using busybox to perform tasks and achieve goals not possible from the basic android toolbox.
Symlinking explained
Commands here
Links here
Scripts here
Now that we have become familiar with busybox, and the android shell, we can make an android app in java using the android sdk and the busybox library.
Android project files
Android package
Comparable programs are rom toolbox pro, root toolbox pro, supersu, etc.