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  3. Introduction to Shell
  • 1

    Manipulating files and directories

    Free

    This chapter is a brief introduction to the Unix shell. You'll learn why it is still in use after almost 50 years, how it compares to the graphical tools you may be more familiar with, how to move around in the shell, and how to create, modify, and delete files and folders.

  • 2

    Manipulating data

    The commands you saw in the previous chapter allowed you to move things around in the filesystem. This chapter will show you how to work with the data in those files. The tools we’ll use are fairly simple, but are solid building blocks.

  • 3

    Combining tools

    The real power of the Unix shell lies not in the individual commands, but in how easily they can be combined to do new things. This chapter will show you how to use this power to select the data you want, and introduce commands for sorting values and removing duplicates.

  • 4

    Batch processing

    Most shell commands will process many files at once. This chapter shows you how to make your own pipelines do that. Along the way, you will see how the shell uses variables to store information.

  • 5

    Creating new tools

    History lets you repeat things with just a few keystrokes, and pipes let you combine existing commands to create new ones. In this chapter, you will see how to go one step further and create new commands of your own.

Initializing

Exercise

How can I edit a file?

Unix has a bewildering variety of text editors. For this course, we will use a simple one called Nano. If you type nano filename, it will open filename for editing (or create it if it doesn't already exist). You can move around with the arrow keys, delete characters using backspace, and do other operations with control-key combinations:

  • Ctrl + K: delete a line.
  • Ctrl + U: un-delete a line.
  • Ctrl + O: save the file ('O' stands for 'output'). You will also need to press Enter to confirm the filename!
  • Ctrl + X: exit the editor.

Instructions

100 XP

Run nano names.txt to edit a new file in your home directory and enter the following four lines:

Lovelace
Hopper
Johnson
Wilson

To save what you have written, type Ctrl + O to write the file out, then Enter to confirm the filename, then Ctrl + X to exit the editor.