After reading this chapter, you should know how to provide an input to commands and print or save its result. You should also be familiar with redirecting an output and input from one command to another. Now, you can easily search, replace strings or pattern in a file, and filter out data based on needs.

From this chapter, we now have a good control on transforming/filtering text data. In next chapter, we will learn how to write more powerful and useful shell scripts by learning loops, conditions, switch, and the most important function in shell. We will also know how important it is to know the exit status of a command. In the next chapter, we will also see more advanced examples of commands that we have learned in this chapter.