Unix, Unix-like, or Linux-based OS provide a lot of powerful features to work upon. Among them, the most powerful and important feature is executing a wide range of commands to perform a task quickly and easily; for example,
grep, and so on. We will come to know about a subset of commands and usages throughout this book. In order to run a command, we need an interface that is widely known as shell.
Shell is a program that acts as an interface between the users (we) and the OS kernel (Linux, Unix, and so on). Understanding in terms of Windows OS, shell serves a similar purpose DOS does. Different shells are available for Unix, Unix-like, or Linux OS. Some of the popular shells are ...