About Bash projects

Unless stated, all your projects will be auto-corrected with Ubuntu 20.04 LTS.

Concepts

For this project, we expect you to look at this concept:

Struggling with the sandbox? Try this: Using Docker & WSL on your local host

Resources

Read or watch:

What Is “The Shell”?
Navigation
Looking Around
A Guided Tour
Manipulating Files
Working With Commands
Reading Man pages
Keyboard shortcuts for Bash
LTS
Shebang

man or help:

cd
ls
pwd
less
file
ln
cp
mv
rm
mkdir
type
which
help
man

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

What does RTFM mean?
What is a Shebang

What is the Shell

What is the shell
What is the difference between a terminal and a shell
What is the shell prompt
How to use the history (the basics)

Navigation

What do the commands or built-ins cd, pwd, ls do
How to navigate the filesystem
What are the . and .. directories
What is the working directory, how to print it and how to change it
What is the root directory
What is the home directory, and how to go there
What is the difference between the root directory and the home directory of the user root
What are the characteristics of hidden files and how to list them
What does the command cd - do

Looking Around

What do the commands ls, less, file do
How do you use options and arguments with commands
Understand the ls long format and how to display it
A Guided Tour
What does the ln command do
What do you find in the most common/important directories
What is a symbolic link
What is a hard link
What is the difference between a hard link and a symbolic link

Manipulating Files

What do the commands cp, mv, rm, mkdir do
What are wildcards and how do they work
How to use wildcards

Working with Commands

What do type, which, help, man commands do
What are the different kinds of commands
What is an alias
When do you use the command help instead of man

Reading Man Pages

How to read a man page
What are man page sections
What are the section numbers for User commands, System calls and Library functions

Keyboard Shortcuts for Bash

Common shortcuts for Bash

LTS

What does LTS mean?

Requirements

General

Allowed editors: vi, vim, emacs
All your scripts will be tested on Ubuntu 20.04 LTS
All your scripts should be exactly two lines long ($ wc -l file should print 2)
All your files should end with a new line (why?)
The first line of all your files should be exactly #!/bin/bash
A README.md file at the root of the repo, containing a description of the repository
A README.md file, at the root of the folder of this project, describing what each script is doing
You are not allowed to use backticks, &&, || or ;
All your scripts must be executable. To make your file executable, use the chmod command: chmod u+x file. Later, we’ll learn more about how to utilize this command.

More Info

Example of line count and first line

julien@ubuntu:/tmp$ wc -l 12-file_type
2 12-file_type
julien@ubuntu:/tmp$ head -n 1 12-file_type
#!/bin/bash
julien@ubuntu:/tmp$

In order to test your scripts, you will need to use this command: chmod u+x file. We will see later what does chmod mean and do, but you can have a look at man chmod if you are curious.

Example

julien@ubuntu:/tmp$ ls
12-file_type
lll
julien@ubuntu:/tmp$ ls -la lll
-rw-rw-r-- 1 julien julien 15 Sep 19 21:05 lll
julien@ubuntu:/tmp$ cat lll
#!/bin/bash
ls
julien@ubuntu:/tmp$ ls -l lll
-rw-rw-r-- 1 julien julien 15 Sep 19 21:05 lll
julien@ubuntu:/tmp$ chmod u+x lll # you do not have to understand this yet
julien@ubuntu:/tmp$ ls -l lll
-rwxrw-r-- 1 julien julien 15 Sep 19 21:05 lll
julien@ubuntu:/tmp$ ./lll
12-file_type
lll
julien@ubuntu:/tmp$

Quiz Questions

Question #0

What command would you use to list files on Linux?

which
pwd
cd
list
ls

Question #1

What does RTFM stand for?

Remember The First Manipulation
Read, Teach, Forget, Migrate
Read The F** Manual

Question #2

What does LTS stand for?

Long Term Support
Long Time Support
Last Terrible Service

Question #3

How do you change directory on Linux?

which
pwd
cd
ls

Tasks

0. Where am I?

Write a script that prints the absolute path name of the current working directory.

Example:

$ ./0-current_working_directory
/root/alx-system_engineering-devops/0x00-shell_basics
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 0-current_working_directory

1. What’s in there?

Display the contents list of your current directory.

Example:

$ ./1-listit
Applications    Documents   Dropbox Movies Pictures
Desktop Downloads   Library Music Public
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 1-listit

2. There is no place like home

Write a script that changes the working directory to the user’s home directory.

You are not allowed to use any shell variables

julien@ubuntu:/tmp$ pwd
/tmp
julien@ubuntu:/tmp$ echo $HOME
/home/julien
julien@ubuntu:/tmp$ source ./2-bring_me_home
julien@ubuntu:~$ pwd
/home/julien
julien@ubuntu:~$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 2-bring_me_home

3. The long format

Display current directory contents in a long format

Example:

$ ./3-listfiles
total 32
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:19 0-current_working_directory
-rwxr-xr-x@ 1 sylvain staff 19 Jan 25 00:23 1-listit
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:29 2-bring_me_home
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:39 3-listfiles
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 3-listfiles

4. Hidden files

Display current directory contents, including hidden files (starting with .). Use the long format.

Example:

$ ./4-listmorefiles
total 32
drwxr-xr-x@ 6 sylvain staff 204 Jan 25 00:29 .
drwxr-xr-x@ 43 sylvain staff 1462 Jan 25 00:19 ..
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:19 0-current_working_directory
-rwxr-xr-x@ 1 sylvain staff 19 Jan 25 00:23 1-listit
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:29 2-bring_me_home
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:39 3-listfiles
-rwxr-xr-x@ 1 sylvain staff 18 Jan 25 00:41 4-listmorefiles
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 4-listmorefiles

5. I love numbers

Display current directory contents.

Long format
with user and group IDs displayed numerically
And hidden files (starting with .)

Example:

$ ./5-listfilesdigitonly
total 32
drwxr-xr-x@ 6 501 20 204 Jan 25 00:29 .
drwxr-xr-x@ 43 501 20 1462 Jan 25 00:19 ..
-rwxr-xr-x@ 1 501 20 18 Jan 25 00:19 0-current_working_directory
-rwxr-xr-x@ 1 501 20 18 Jan 25 00:23 1-listfiles
-rwxr-xr-x@ 1 501 20 19 Jan 25 00:29 2-bring_me_home
-rwxr-xr-x@ 1 501 20 20 Jan 25 00:39 3-listfiles
-rwxr-xr-x@ 1 501 20 18 Jan 25 00:41 4-listmorefiles
-rwxr-xr-x@ 1 501 20 18 Jan 25 00:43 5-listfilesdigitonly
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 5-listfilesdigitonly

6. Welcome

Create a script that creates a directory named my_first_directory in the /tmp/ directory.

Example:

$ ./6-firstdirectory
$ file /tmp/my_first_directory/
/tmp/my_first_directory/: directory
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 6-firstdirectory

7. Betty in my first directory

Move the file betty from /tmp/ to /tmp/my_first_directory.

Example:

$ ./7-movethatfile
$ ls /tmp/my_first_directory/
betty
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 7-movethatfile

8. Bye bye Betty

Delete the file betty.

The file betty is in /tmp/my_first_directory

Example:

$ ./8-firstdelete
$ ls /tmp/my_first_directory/
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 8-firstdelete

9. Bye bye My first directory

Delete the directory my_first_directory that is in the /tmp directory.

Example:

$ ./9-firstdirdeletion
$ file /tmp/my_first_directory
/tmp/my_first_directory: cannot open `/tmp/my_first_directory' (No such file or directory)
$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 9-firstdirdeletion

10. Back to the future

Write a script that changes the working directory to the previous one.

julien@ubuntu:/tmp$ pwd
/tmp
julien@ubuntu:/tmp$ cd /var
julien@ubuntu:/var$ pwd
/var
julien@ubuntu:/var$ source ./10-back
/tmp
julien@ubuntu:/tmp$ pwd
/tmp

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 10-back

11. Lists

Write a script that lists all files (even ones with names beginning with a period character, which are normally hidden) in the current directory and the parent of the working directory and the /boot directory (in this order), in long format.

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 11-lists

12. File type

Write a script that prints the type of the file named iamafile. The file iamafile will be in the /tmp directory when we will run your script.

Example

ubuntu@ip-172-31-63-244:~$ ./12-file_type
/tmp/iama- File: ELF 64-bit LSB  executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=bd39c07194a778ccc066fc963ca152bdfaa3f971, stripped

Note that depending on the file, the output of your script will be different.

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 12-file_type

13. We are symbols, and inhabit symbols

Create a symbolic link to /bin/ls, named __ls__. The symbolic link should be created in the current working directory.

ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la
total 144
drwxrwxr-x  2 ubuntu ubuntu   4096 Sep 20 03:24 .
drwxrwxrwt 12 root   root   139264 Sep 20 03:24 ..
ubuntu@ip-172-31-63-244:/tmp/sym$./13-symbolic_link
ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la
total 144
drwxrwxr-x  2 ubuntu ubuntu   4096 Sep 20 03:24 .
drwxrwxrwt 12 root   root   139264 Sep 20 03:24 ..
lrwxrwxrwx  1 ubuntu ubuntu      7 Sep 20 03:24 __ls__ -> /bin/ls

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 13-symbolic_link

14. Copy HTML files

Create a script that copies all the HTML files from the current working directory to the parent of the working directory, but only copy files that did not exist in the parent of the working directory or were newer than the versions in the parent of the working directory.

You can consider that all HTML files have the extension .html

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 14-copy_html

15. Let’s move

Create a script that moves all files beginning with an uppercase letter to the directory /tmp/u.

You can assume that the directory /tmp/u will exist when we will run your script

ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la
total 148
drwxrwxr-x  3 ubuntu ubuntu   4096 Sep 20 03:33 .
drwxrwxrwt 12 root   root   139264 Sep 20 03:26 ..
-rw-rw-r--  1 ubuntu ubuntu      0 Sep 20 03:32 My_file
lrwxrwxrwx  1 ubuntu ubuntu      7 Sep 20 03:24 __ls__ -> /bin/ls
-rw-rw-r--  1 ubuntu ubuntu      0 Sep 20 03:32 Elif_ym
-rw-rw-r--  1 ubuntu ubuntu      0 Sep 20 03:32 random_file
ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la /tmp/u
total 8
drwxrwxr-x 2 ubuntu ubuntu 4096 Sep 20 03:33 .
drwxrwxr-x 3 ubuntu ubuntu 4096 Sep 20 03:33 ..
ubuntu@ip-172-31-63-244:/tmp/sym$ ./100-lets_move
ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la
total 148
drwxrwxr-x  3 ubuntu ubuntu   4096 Sep 20 03:33 .
drwxrwxrwt 12 root   root   139264 Sep 20 03:26 ..
lrwxrwxrwx  1 ubuntu ubuntu      7 Sep 20 03:24 __ls__ -> /bin/ls
-rw-rw-r--  1 ubuntu ubuntu      0 Sep 20 03:32 random_file
ubuntu@ip-172-31-63-244:/tmp/sym$ ls -la /tmp/u
total 8
drwxrwxr-x 2 ubuntu ubuntu 4096 Sep 20 03:33 .
drwxrwxr-x 3 ubuntu ubuntu 4096 Sep 20 03:33 ..
-rw-rw-r-- 1 ubuntu ubuntu    0 Sep 20 03:32 My_file
-rw-rw-r-- 1 ubuntu ubuntu    0 Sep 20 03:32 Elif_ym

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 100-lets_move

16. Clean Emacs

Create a script that deletes all files in the current working directory that end with the character ~.

ubuntu@ip-172-31-63-244:/tmp/sym$ ls
main.c  main.c~  Makefile~
ubuntu@ip-172-31-63-244:/tmp/sym$ ./101-clean_emacs
ubuntu@ip-172-31-63-244:/tmp/emacs$ ls
main.c
ubuntu@ip-172-31-63-244:/tmp/emacs$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 101-clean_emacs

17. Tree

Create a script that creates the directories welcome/, welcome/to/ and welcome/to/school in the current directory.

You are only allowed to use two spaces (and lines) in your script, not more.

julien@ubuntu:/tmp/h$ ls -l
total 4
-rwxrw-r-- 1 julien julien 44 Sep 20 12:09 102-tree
julien@ubuntu:/tmp/h$ wc -l 102-tree
2 102-tree
julien@ubuntu:/tmp/h$ head -1 102-tree
#!/bin/bash
julien@ubuntu:/tmp/h$ tr -cd ' ' < 102-tree | wc -c # you do not have to understand this yet, but the result should be 2, 1 or 0
2
julien@ubuntu:/tmp/h$ ./102-tree
julien@ubuntu:/tmp/h$ ls
102-tree  welcome
julien@ubuntu:/tmp/h$ ls welcome/
to
julien@ubuntu:/tmp/h$ ls -l welcome/to
total 4
drwxrwxr-x 2 julien julien 4096 Sep 20 12:11 school
julien@ubuntu:/tmp/h$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 102-tree

18. Life is a series of commas, not periods

Write a command that lists all the files and directories of the current directory, separated by commas (,).

Directory names should end with a slash (/)
Files and directories starting with a dot (.) should be listed
The listing should be alpha ordered, except for the directories . and .. which should be listed at the very beginning
Only digits and letters are used to sort; Digits should come first
You can assume that all the files we will test with will have at least one letter or one digit
The listing should end with a new line

ubuntu@ubuntu:~/$ ls -a

.  ..  0-commas  0-commas-checks  1-empty_casks  2-gifs  3-directories  4-zeros  5-rot13  6-odd  7-sort_rot13  Makefile  quote  .test  test_dir  test.var

ubuntu@ubuntu:~/$ ./103-commas

./, ../, 0-commas, 0-commas-checks/, 1-empty_casks, 2-gifs, 3-directories, 4-zeros, 5-rot13, 6-odd, 7-sort_rot13, Makefile, quote, .test, test_dir/, test.var

ubuntu@ubuntu:~/$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: 103-commas

19. File type: School

Create a magic file school.mgc that can be used with the command file to detect School data files. School data files always contain the string SCHOOL at offset 0.

ubuntu@ip-172-31-63-244:/tmp/magic$ cp /bin/ls .
ubuntu@ip-172-31-63-244:/tmp/magic$ ls -la
total 268
drwxrwxr-x  2 ubuntu ubuntu   4096 Sep 20 02:44 .
drwxrwxrwt 11 root   root   139264 Sep 20 02:44 ..
-rw-r--r--  1 ubuntu ubuntu    496 Sep 20 02:42 school.mgc
-rwxr-xr-x  1 ubuntu ubuntu 110080 Sep 20 02:43 ls
-rw-rw-r--  1 ubuntu ubuntu     50 Sep 20 02:06 thisisaschoolfile
-rw-rw-r--  1 ubuntu ubuntu     30 Sep 20 02:16 thisisatextfile
ubuntu@ip-172-31-63-244:/tmp/magic$ file --mime-type -m school.mgc *
school.mgc:         application/octet-stream
ls:                    application/octet-stream
thisisaschool- File: School
thisisatext- File:       text/plain
ubuntu@ip-172-31-63-244:/tmp/magic$ file -m school.mgc *
school.mgc:         data
ls:                    data
thisisaschool- File: School data
thisisatext- File:       ASCII text
ubuntu@ip-172-31-63-244:/tmp/magic$

Repo:

GitHub repository: alx-system_engineering-devops
Directory: 0x00-shell_basics
File: school.mgc

Files

README.md

Latest commit

History

README.md

File metadata and controls

About Bash projects

Concepts

Resources

man or help:

Learning Objectives

General

What is the Shell

Navigation

Looking Around

Manipulating Files

Working with Commands

Reading Man Pages

Keyboard Shortcuts for Bash

LTS

Requirements

General

More Info

Quiz Questions

Question #0

Question #1

Question #2

Question #3

Tasks

0. Where am I?

1. What’s in there?

2. There is no place like home

3. The long format

4. Hidden files

5. I love numbers

6. Welcome

7. Betty in my first directory

8. Bye bye Betty

9. Bye bye My first directory

10. Back to the future

11. Lists

12. File type

13. We are symbols, and inhabit symbols

14. Copy HTML files

15. Let’s move

16. Clean Emacs

17. Tree

18. Life is a series of commas, not periods

19. File type: School