1. First Steps

Question 1

What is a shell?

Answer 1

A shell is a program that you use to run other programs through a text-only interface called the command line.

Question 2

What does a shell allow us to do?

Answer 2

Simple things like starting your browser or complicated things like executing a set of transformations on data from multiple files.

Question 3

What does UNIX bring to the table in terms of utilities and what’s the shell’s responsibility in this?

Answer 3

A huge ecosystem of command line tools. Shell is the glue that makes these tools work together.

Question 4

What can be said about the shell in terms of automation?

Answer 4

Shell is a very powerful tool for automating tasks that you repeat often.

Question 5

What six areas do the shell help the most?

Answer 5

1. File Management
2. System Administration
3. Software Development
4. Data Filtering and Transformations
5. Remote Access
6. Scripting

Question 6

What scripting language has been dominating the UNIX world since the mid-nineties?

Answer 6

Bourne Again SHell (Bash)

Question 7

What shell did MacOS switch to on the Catalina release?

Answer 7

Z Shell (Zsh)

Question 8

What can we think of Zsh as in relation to Bash?

Answer 8

We can think of Z Shell as a more configurable version of Bash with some extra features.

Question 9

How can you undelete or undo in the shell?

Answer 9

YOU CANNOT! The shell is a power tool. You must be careful. There is no undelete or undo.

Question 10

What is the shell limited to?

Answer 10

Mostly to text. We enter and edit text and a text output gets returned. Shell doesn’t know about the font colors, graphical display, mouse colors, etc.

Question 11

What is a shell ran inside?

Answer 11

Terminal emulator.

Question 12

What is a terminal emulator?

Answer 12

It’s a layer between the shell and your hardware — it takes keystrokes from your keyboard and translates them to the so-called control coach that the shell understands. It takes a text output from the shell and displays it in nice graphical fonts to the user.

Question 13

What is the prompt?

Answer 13

It’s the text that you see when you start your shell. It’s shown when the shell is waiting for your command.

Question 14

How do you list the contents of your current directory in shell?

Answer 14

By executing the ls command.

eg. ls

Question 15

How do you move into another directory in shell?

Answer 15

By executing the cd command alongside the path to navigate to.

eg. cd ~/Documents

Question 16

How do you move one directory up from the directory you’re currently at in shell?

Answer 16

By executing the cd command on its own.

eg. cd

Question 17

How do you log into another shell using secure shell in shell?

Answer 17

By executing the ssh command alongside the system path.

eg. ssh reindert@codesensei.nl

Question 18

How do you exit the secure shell that you used to log into another shell in shell?

Answer 18

By executing the exit command.

eg. exit

Question 19

How do you exit the shell and end your session?

Answer 19

By executing the exit command.

eg. exit