This document provides an overview of a practical Linux workshop led by Arie Bregman, covering the essentials of the Linux operating system, its usage, and basic terminal commands. Participants engage in hands-on practice with commands like pwd, cd, ls, mkdir, and more, while also learning about file manipulation, permissions, and scripting. The session concludes with a final exercise and outlines potential future topics for further exploration in Linux and related technologies.

1. (Practical) Linux 101
Arie Bregman
Senior Software Engineer @RedHat

2. Agenda
● What is Linux?
● Why Linux?
● Practice time!
● More practice
● Yes, more practice
● Questions

3. What is Linux?
● Operating System
Where can you find it?
● Smartphones
● 96% of 500 top supercomputers
● TVs
● Rifles
● Self-driving cars

4. Why Linux?
Apache HTTP server usage research
● Free
● Open Source
● Choose your own flavor
● Community
● The foundation for some job positions

5. Before we start...
● Linux is case sensitive
○ A != a
● Don’t be afraid experimenting. It’s OK if you break stuff :)
○ Small note: don’t experiment on production
● Don’t expect feedback (like smiley) every time you execute a command.
● Everything we’ll do is distro-agnostic at this meetup
● ASK QUESTIONS

6. Enough talking. Practice Time!
First, open your terminal

8. First command: pwd
● Print working/current directory
● Answers the question “Where Am I?”
3 Directories:
● /
● home
● arie
[arie@localhost ~]$ pwd
/home/arie

9. cd
● Change the current directory to another dir
● Try changing directory to /tmp and type ‘pwd’. What do you see?
[arie@localhost ~]$ cd /tmp
[arie@localhost ~]$ cd $HOME
[arie@localhost ~]$ cd ~
[arie@localhost ~]$ cd ..
You can see all shell variables by
running ‘set’ [arie@localhost ~]$ cd -

10. ls
● List directory contents and information
● Useful arguments
○ -a for hidden files
○ -l for long listing format
○ -F -> can you guess what it does?
[arie@localhost ~]$ ls
pictures docs file
[arie@localhost ~]$ ls /tmp
a b c
# How do I know if they are
directories, regular files or perhaps
some are directories and some are
regular?

11. Type of files
● “Everything is a file” in Linux
○ Regular
○ Directory
○ Block
○ Link
○ Socket
● In every directory you’ll find two hidden files:
○ ..
○ .

12. mkdir
● Create a directory
● Useful argument: -p for creating multiple directories at once
[arie@localhost ~]$ mkdir new
[arie@localhost ~]$ mkdir /tmp/new
[arie@localhost ~]$ mkdir /tmp/a/b
mkdir: cannot create directory
‘/tmp/a/b’: Not a directory
● After creating a new directory,
run ‘ls -lF’
● Try also ‘ls -ld new’
[arie@localhost ~]$ mkdir -p /tmp/a/b

13. touch
● Create files and modify their timestamp
[arie@localhost ~]$ touch new_file
[arie@localhost ~]$ touch a b
● After creating a new file, try to ‘touch’ it again.
Can you see its timestamp changed?

14. Pause
● Questions so far?
○ How many commands left to learn?
■ 2000 installed, more than 10,000,000 uninstalled
○ I don’t like typing. Is there a way I can use only my mouse?
■ Get out of the room
○ How am I supposed to remember all the commands?
■ MORE practice

15. Exercise
● Go to /tmp directory and create there a directory called pizza
● In your new directory, create 3 files named after toppings you like on your pizza
○ If you don’t like pizza, get out of the room
● Verify they have been created (in pizza directory)
● Go back to your home directory Did you know? Every time you’ll
reboot your operating system, the
files and directories in /tmp will be
removed!
Bonus Exercise
● In /tmp create a directory called ‘ten_files’
● Create there 10 files called ‘file1, file2, file3, …’
Commands we learned so far:
pwd - current location
cd - change directory
ls - list content
mkdir - create directory
touch - create empty file

16. Solution
Bonus Solution
[arie@localhost ~]$ cd /tmp
[arie@localhost ~]$ mkdir pizza
[arie@localhost ~]$ cd pizza
[arie@localhost ~]$ touch mushrooms mozzarella tomatoes
[arie@localhost ~]$ ls
mushrooms mozzarella tomatoes
[arie@localhost ~]$ cd ~
[arie@localhost ~]$ cd /tmp
[arie@localhost ~]$ touch file{1..10}
The strange code for creating the 10
files ({1..10}) is called brace
expansion and provided by bash for
easily creating long and complex
combinations

17. Zoom Out
Hardware
Linux Kernel
Shell
Terminal

18. echo
● Display a line of text
● You can create a new file using echo
[arie@localhost ~]$ echo “Look mom, I know
Linux!”
Look mom, I know Linux
[arie@localhost ~]$ echo “Amazing” > new_file

19. I/O Redirection
● Manipulation of I/O
● Three streams
○ stdin (Input) -> 0
○ stdout (Output) -> 1
○ stderr (Error) -> 2
● > for output redirection
● < for input redirection
● 2> for error
● Use ‘>>’ for appending
● 2>&1 redirect error to output target
[arie@localhost ~]$ blabla
blabla: command not found...
[arie@localhost ~]$ blabla 2> error_info
[arie@localhost ~]$ echo 1 > my_echos
[arie@localhost ~]$ echo 2 > my_echos
[arie@localhost ~]$ cat my_echos
2
[arie@localhost ~]$ echo 1 > my_echos
[arie@localhost ~]$ echo 2 >> my_echos
[arie@localhost ~]$ cat my_echos
1
2

20. cat
● Concatenate files.
● Probably most common use: read files :)
● You can also create files with content
[arie@localhost ~]$ cat /etc/passwd
Did you know? /etc/passwd used for
storing data on all users in the
system and their information (e.g.
home directory, shell, …)
[arie@localhost ~]$ echo “a” > file1
[arie@localhost ~]$ echo “b” > file2
[arie@localhost ~]$ cat file1 file2
a
b
[arie@localhost ~]$ echo > file3
Hello
there
(Press ctrl+d)
[arie@localhost ~]$ cat file3
Hello
there

21. mv
● Move files
● Also rename files
[arie@localhost ~]$ touch new
[arie@localhost ~]$ mv new /tmp/
[arie@localhost ~]$ ls /tmp
new
[arie@localhost ~]$ touch x
[arie@localhost ~]$ ls
x
[arie@localhost ~]$ mv x y
[arie@localhost ~]$ ls
y

22. Exercise 2
● Create a file called kit
● Move the file to /tmp and rename its name to kat
● Add the line “I was kit, now I’m kat” to the file
● Read the file to make sure the line is there
● Now add another line to the file “I’m complete”
New commands we learned:
cat - read file
Mv - move and rename
echo - print a line
Bonus Exercise
● Create a file called x with the string “It’s”
● Create a file called y with the string “Amazing”
● Create a third file (without touch or echo!) called fusion with the
content of x and the content of y

23. Solution
Bonus Solution
[arie@localhost ~]$ touch kit
[arie@localhost ~]$ mv kit /tmp/kat
[arie@localhost ~]$ echo “I was kit, now I’m kat” > /tmp/kat
[arie@localhost ~]$ cat /tmp/kat
I was kit, now I’m kat
[arie@localhost ~]$ echo “I’m complete” >> /tmp/kat
[arie@localhost ~]$ echo “It’s” > x
[arie@localhost ~]$ echo “Amazing” > y
The strange code for creating the 10
files ({1..10}) is called brace
expansion and provided by bash for
easily creating long and complex
combinations

24. rm
● Remove files or directories
[arie@localhost ~]$ touch x
[arie@localhost ~]$ ls
x
[arie@localhost ~]$ rm x
[arie@localhost ~]$ ls x
ls: cannot access 'x': No such file or directory
[arie@localhost ~]$ mkdir directory
[arie@localhost ~]$ rm directory
rm: cannot remove 'directory': Is a directory
[arie@localhost ~]$ rm -r directory
[arie@localhost ~]$ ls
● Useful arguments
○ -r for removing directory its content
○ -i -> prompt before every removal

25. cp
● copy files and directories
[arie@localhost ~]$ touch x
[arie@localhost ~]$ cp x y
[arie@localhost ~]$ ls
x y
[arie@localhost ~]$ mkdir directory
[arie@localhost ~]$ touch directory/y
[arie@localhost ~]$ cp -r directory /tmp/● Useful arguments
○ -r -> like with rm, for copying an
entire directory and its content

26. && (logical AND)
● Syntax: [command1] && [command2] && …
● The command after && will run only if the
command before && ran successfully
[arie@localhost ~]$ touch x
[arie@localhost ~]$ ls && echo “ls worked!”
x
ls worked
[arie@localhost ~]$ bla && echo “bla worked!”
bla: command not found

27. || (logical OR)
● Syntax: [command1] || [command2] || …
● The command after || will run only if the
command before || failed
[arie@localhost ~]$ touch x
[arie@localhost ~]$ ls || echo “amazing!”
x

28. man
● Manual references
● Try it for yourself:
○ man pwd
○ man ls
○ man rm
○ ...
You can even run ‘man man’

29. Vim - first steps
● Two modes
○ Insert - for writing text (enter this mode by typing
‘i’)
○ Normal - manipulate text without writing text by
yourself (enter this mode by clicking on ‘ESC’)
● Basic commands in normal mode
○ x - delete a character
○ o - newline
○ G - go to the end of the file
○ g - go the beginning of the file
● Quit Vim
○ Without saving, type in normal mode: :q!
○ With saving, type in normal mode: wq!
■ I prefer ZZ

30. sudo
● Try the following commands:
○ touch x
○ mv x /opt
● Why did it fail?
○ If it didn’t fail, you are using root. Never work as root!
● Sudo Access
○ Run commands as root
● How to gain sudo?
○ visudo
○ Add the line: ‘<user> ALL=(ALL) NOPASSWD: ALL’
● How to switch to root account
○ su -
○ Don’t switch to root account!

31. Final Exercise!
● Create a file with the content “Look mom, I am a Linux expert!” and call it
“linux_expert”
● Change the name of the file you just created to “linux_newbie”
● Make a copy of the file called “linux_newbie.backup”
● Delete the original file (linux_newbie)
● Change the content of the file to “Look mom, I am a Linux newbie”
● Create a directory in /usr called ‘my_files’
● Move the file to /usr/my_files
● Add the line “I’m going to be an expert!” to the file

32. It’s almost time to say goodbye...
● Possible topics for next meetups
○ (Practical) Linux 102 (and 103, 104, …)
○ Linux Scripting
○ Networking For Newbies
○ Git basics & Advanced Git.
○ Python or not to be
● DevOps Oriented
○ CI/CD with Jenkins & Kubernetes
○ Configuration Management with Ansible
○ Monitoring with Prometheus
○ Logging with Logstash
○ Building Web Applications with Flask

33. Thank You
● Everything is uploaded to GitHub
○ Linux
○ Computer Networking
○ Jenkins Goodies
○ More on GitHub
● Questions?