Although Ubuntu is a desktop-driven OS, the system is running on a powerful and incredibly flexible command-line core. Inspired by more than 30 years of UNIX heritage, the command-line environment present on Linux systems enables you to perform some incredibly powerful tasks by stringing together different commands in different ways.
The philosophy behind UNIX is to create a large number of small tools, each of which is designed to do one task but do it incredibly well. As a quick example to whet your appetite, there is a command called ls that does nothing more than list files in a folder. Although listing files is its singular function in life, it has every option imaginable for listing files.
Now, ls is limited by itself, but it can be combined with other commands that have equal levels of flexibility to create impressively powerful combinations. To do this, a pipeline is created using the | symbol to connect these different commands. Pipelines can be constructed in any number of different ways, and once the user has even a basic knowledge of what a few different commands do, stringing together a pipeline of commands can solve virtually any task you can imagine in quick and powerful ways.
It should be made 100 percent clear that using the command line is not an essential skill required to use Ubuntu, but it is a skill that can increase the flexibility of your computer for more advanced, customized tasks. Rather than cover the use of the terminal here, we have included an excellent introduction in Appendix A.