Shell, bash and bash scripts - cogeorg/teaching GitHub Wiki

The command effectively represents a way to interact with a PC, as opposed to the graphical user interface (GUI) you are all familiar with. Specifically, the command line interacts with the PC’s macroprocessor, which we call the shell. There are many different shell’s, but we’ll focus on the most widely used one - Bourne Again Shell, or simply, bash. In other words, the bash represents one specific command line interpreter, which turns your code into something your PC understands.

We can use the bash shell to execute actions or to call particular scripts we may have written, in say Python or R. When can string together multiple lines of bash code, save it in a script with a .sh suffix - we call this a bash script, which can also be executed directly from the command line.

Section 5 of the Codecademy command line tutorial mentioned previously, has a great example.