system_admin_flashcards

Question 1

Linux Basics :: Linux is an open-source operating system kernel that

Question 2

powers many distributions. Distribution (Distro) :: A packaged version

Question 3

of Linux that includes the kernel

Answer 3

tools

Question 4

Fedora

Answer 4

Debian). Kernel :: The core of the OS

Question 5

resources and system calls. Shell :: A command interpreter that lets

Question 6

users interact with the OS (bash

Answer 6

zsh). Command Line Interface (CLI) ::

Question 7

Text-based way to execute commands directly. Man Pages :: Built-in Linux

Question 8

manual accessed with man <command></command>. Absolute Path :: Full file path

Question 9

starting from root /. Relative Path :: File path relative to the current

Question 10

working directory. File Permissions :: Define who can read (r)

Answer 10

write

Question 11

(w)

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and execute (x) a file. Permission Groups :: User (u)

Question 12

Others (o). Changing Permissions :: Use chmod to change permissions.

Question 13

Example: chmod 755 file.sh. Changing Ownership :: Use chown to change

Question 14

file owner and group. Hidden Files :: Files starting with .; view with

Question 15

ls -a. Superuser (root) :: Administrative account with full system

Question 16

privileges. Sudo :: Command to execute tasks with root privileges.

Question 18

Create File :: touch filename Create Directory :: mkdir dirname List

Question 19

Files :: ls (options: -l

Answer 19

-a

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Move/Rename File :: mv source destination Remove File :: rm filename

Question 21

Remove Directory :: rmdir dirname or rm -r dirname View File Content ::

Question 22

cat

Answer 22

less

Question 24

View Running Processes :: ps

Answer 24

top

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kill -9 PID Background Process :: Run command with & at the end.

Question 26

Foreground Process :: Bring background job with fg.

Question 28

User Account :: A record that defines a person’s access to the system.

Question 29

Add User :: sudo adduser username Delete User :: sudo deluser username

Question 30

Switch User :: su - username Group Account :: A collection of users

Question 31

sharing permissions. Add Group :: sudo groupadd groupname Add User to

Question 32

Group :: sudo usermod -aG groupname username Delete Group ::

Question 33

sudo groupdel groupname Check Groups of User :: groups username

Question 35

Numeric Permission Values :: r=4

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w=2

Question 36

(e.g.

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755). Check Permissions :: ls -l shows permissions. Set User

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Ownership :: sudo chown user file Set Group Ownership ::

Question 38

sudo chgrp group file

Question 40

Check IP Address :: ip addr or ifconfig Ping Test :: ping hostname Check

Question 41

Ports :: netstat -tuln or ss -tuln SSH Connection :: ssh user@hostname

Question 42

Copy Over SSH :: scp file user@host:/path Firewall Management ::

Question 43

ufw enable

Answer 43

ufw allow 22

Question 45

Check Disk Usage :: df -h Check Memory Usage :: free -h Check System

Question 46

Logs :: journalctl

Answer 46

/var/log/ files System Update ::

Question 47

sudo apt update && sudo apt upgrade Package Install (Debian) ::

Question 48

sudo apt install package Package Install (Red Hat) ::

Question 49

sudo yum install package