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Difference between revisions of "ITIC:Working in the shell - Introduction to Bash - Exercises"

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(Exercises: Exercises on files, directories etc.)
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There are exercises linked below to other parts of this wiki, as a backup (if we don't have time to write new ones) and also as a bonus for the ambitious students, if we do have time to write new ones.
 
There are exercises linked below to other parts of this wiki, as a backup (if we don't have time to write new ones) and also as a bonus for the ambitious students, if we do have time to write new ones.
 
=Exercises=
 
=Exercises=
 
+
== Basics ==
 +
A ''shell'' is a program that can be run interactively, e.g. in a terminal (or terminal emulator). Describe the terms (use a search engine, our Swedish compendium or the previous page if you need help):
 +
* shell
 +
* terminal
 +
* command line
 +
* command line interface
 
== File system navigation ==
 
== File system navigation ==
 +
Start a new terminal. Use <code>pwd</code> to notice where you are in the file system. What is this directory called in general terms?
 +
 +
Issue the following command:
 +
<source lang="Bash">
 +
$ echo ~
 +
</source>
 +
Notice the output from echo. It seems that Bash has expanded the <code>~</code> to a path. What path is that?
 +
 +
Change directory to one of the directories that are in your current directory. You use <code>cd</code> to change directory. But what do you need to write after the <code>cd</code> command (as an argument) for it to know what to do?
 +
 +
What happens if you, from any directory, simply issues the command <code>cd</code> without any arguments? Try it.
 +
 +
Change directory again, from your home directory to some other directory. Issue the command <code>pwd</code>. Then issue the command <code>cd -</code> (that is, <code>cd</code> with the argument of a single ''dash'' <code>-</code>). Where did you end up? Issue <code>cd -</code> again. Where did you end up this time? Do it again, and again, until you figure it out.
 +
 +
In your home directory, issue the command <code>tree</code> without arguments. What does it list? Next, issue the command <code>pwd</code> again, but give it an argument of one of the directories in your current directory (e.g. Documents, Desktop, Music, Downloads etc - try all of them or if you don't have any of them, use an existing directory as the argument).
 +
 +
In your home directory, use <code>ls</code> with the appropriate flag (or flags) to list all files and directories in a way that shows you which ones are files, and which ones are directories.
 +
 +
Next, issue the command <code>ls</code> (without any arguments) and notice what files and directories are listed. Next, issue the command <code>ls -a</code> and notice what additional files and directories are listed. The additional files and folders you see, look at their names and make a note of what they have in common.
  
Commands: cd, ls, pwd, tree
+
Next, create a directory (you may use <code>mkdir</code> to do this) called <code>.this-is-a-test</code> (note the leading dot in the file name). Run <code>ls</code> without arguments. Is the new directory listed? Use <code>ls -a</code> to list all files again. Was the new directory listed?
  
 +
Use <code>rmdir</code> to delete the new directory.
 
== Issuing commands ==
 
== Issuing commands ==
  

Revision as of 08:00, 12 September 2019

Shells - there are many shells out there, and Bash is one of them

TODO: Write exercises before October 9 2019 (at the very latest).

There are exercises linked below to other parts of this wiki, as a backup (if we don't have time to write new ones) and also as a bonus for the ambitious students, if we do have time to write new ones.

Exercises

Basics

A shell is a program that can be run interactively, e.g. in a terminal (or terminal emulator). Describe the terms (use a search engine, our Swedish compendium or the previous page if you need help):

  • shell
  • terminal
  • command line
  • command line interface

File system navigation

Start a new terminal. Use pwd to notice where you are in the file system. What is this directory called in general terms?

Issue the following command:

$ echo ~

Notice the output from echo. It seems that Bash has expanded the ~ to a path. What path is that?

Change directory to one of the directories that are in your current directory. You use cd to change directory. But what do you need to write after the cd command (as an argument) for it to know what to do?

What happens if you, from any directory, simply issues the command cd without any arguments? Try it.

Change directory again, from your home directory to some other directory. Issue the command pwd. Then issue the command cd - (that is, cd with the argument of a single dash -). Where did you end up? Issue cd - again. Where did you end up this time? Do it again, and again, until you figure it out.

In your home directory, issue the command tree without arguments. What does it list? Next, issue the command pwd again, but give it an argument of one of the directories in your current directory (e.g. Documents, Desktop, Music, Downloads etc - try all of them or if you don't have any of them, use an existing directory as the argument).

In your home directory, use ls with the appropriate flag (or flags) to list all files and directories in a way that shows you which ones are files, and which ones are directories.

Next, issue the command ls (without any arguments) and notice what files and directories are listed. Next, issue the command ls -a and notice what additional files and directories are listed. The additional files and folders you see, look at their names and make a note of what they have in common.

Next, create a directory (you may use mkdir to do this) called .this-is-a-test (note the leading dot in the file name). Run ls without arguments. Is the new directory listed? Use ls -a to list all files again. Was the new directory listed?

Use rmdir to delete the new directory.

Issuing commands

Working with text files

Commands: wc, grep,

Combining commands with pipes

Editing the commands line and some other tricks

Exit status

Blobbing and expansion

Introduction to shell expansion

Environment variables

Variables: $ ? PATH HOME LANG USER

Network

We will add exercises here when we have the time. See below for now.

Swedish exercises

Here are links to our Swedish compendium (which contains a lot of Bash), and the companion Swedish exercise PDF (which has a lot of Bash exercises).

Bonus exercises

These are some recommended exercise pages from other parts of this wiki:

Links

Where to go next

The next page is Networks_and_protocols.

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