Linux

Question 1

What is Linux

Answer 1

Open Source OS
UNIX alternative
Highly customizable
Many home IoT devices use it

Question 2

Linux Kernel

Answer 2

Core of Linux OS
Establishes communication between software and hardware

Question 3

Kernel’s Responsibilities

Answer 3

Device, Memory, and Process Management
Handling system calls

Question 4

File Manager

Answer 4

Allows users to access files in the system

Question 5

Desktop Environment

Answer 5

Provides a user-friendly GUI

Question 6

Package Manager

Answer 6

Used to download, install, and update applications

Question 7

/bin and /sbin

Answer 7

Store binaries

Question 8

/media and /mnt

Answer 8

Used to mount drives

Question 9

/home

Answer 9

Stores personal user files

Question 10

/tmp

Answer 10

Stores temporary files (do not save personal files in this directory)

Question 11

/etc

Answer 11

Important: system configurations files
Directory

Question 12

/var

Answer 12

Stores system logs

Question 13

/boot

Answer 13

Kernel image

Question 14

/sys

Answer 14

Interface to the kernel

Question 15

/proc

Answer 15

A directory for each running process, including kernel processes

Question 16

Root User

Answer 16

Highest Privileges
Can perform any task
Shown by # in CLI

Question 17

Sudo Users

Answer 17

Can perform only what they are permitted to do in the system

Question 18

Regular Users

Answer 18

Can perform only basic tasks in the system
Shown by $ in CLI

Question 19

whoami

Answer 19

Returns current user name

Question 20

pwd

Answer 20

Print Working Directory
Finds current system location

Question 21

uname

Answer 21

Gets info about the operating system

Question 22

touch

Answer 22

Command that creates a file

Question 23

mkdir

Answer 23

Command creates directories and folders

Question 24

Cat

Answer 24

Concatenate

Reads data from the file and gives its content as output

Question 25

Relative Path

Answer 25

Navigation to directories w/o specifying the root and relative to the working directory

Question 26

Absolute Path

Answer 26

/ Indicated root folder

Question 27

>

Answer 27

Outputs and overwrites a file

Question 28

>>

Answer 28

Appends the output to a file

Question 29

<

Answer 29

Input

Question 30

STDIN

Answer 30

Standard Input taking text as an input 0

Question 31

STDOUT

Answer 31

Standard Output used to test output of any command you type in the terminal, and then that output is stored in the stdout stream 1

Question 32

STDERR

Answer 32

Standard Error is invoked whenever a command faces an error, then that error message gets stored in this data stream 2

Question 33

grep

Answer 33

Filters data

Question 34

/etc/shadow

Answer 34

Contains encrypted passwords Need to be Root or Root privilaged

Question 35

R

Answer 35

Read 4

Question 36

W

Answer 36

Write 2

Question 37

X

Answer 37

Execute 1

Question 38

Path

Answer 38

Environment variable Instructs the shell to find an executable path Paths are separated with : colons

Question 39

apt update

Answer 39

Updates package lists for upgrades

Question 40

apt upgrade

Answer 40

Installs all available package updates

Question 41

dmesg

Answer 41

Displays messages from the kernel ring buffer. Diagnostic tool for failures

Question 42

dhclient

Answer 42

IP addresses can be changed, released, renewed, or removed

Question 43

/etc/network/interfaces

Answer 43

Configure network interfaces

Question 44

What 2 commands can start a service

Answer 44

Service systemctl

Question 45

netstat

Answer 45

NOT installed by default

Question 46

Samba

Answer 46

Allows computers to communicate within the local network via SMB protocol. Port 137-139 and 445

Question 47

SCP

Answer 47

Secure Copy Protocol Securely transfer files between remote & local stations Can use flags to set parameters

Question 48

Bash

Answer 48

Bourne Again SHell Scripting includes system commands. File extension .sh Automates tasks First line #!/bin/bash

Question 49

$ # " "

Answer 49

Variable Comment Text

Question 50

sed

Answer 50

Command used to replace words

Question 51

chmod

Answer 51

Command to change permissions of a file or directory

Question 52

iptables

Answer 52

Protects from possible attacks Firewall

Question 53

smb.conf

Answer 53

File to be edited to set up Samba services

Question 54

Fail2ban

Answer 54

Daemon that protects against brute force attacks

Question 55

What is used for math

Answer 55

let expr (( ))

Question 56

/etc/skel

Answer 56

Where templates for new users are stored

Question 57

cd/

Answer 57

Command to get to the root directory

Question 58

Apache

Answer 58

Web server