1.1 Summarize Linux Fundamentals

Question 1

/boot

Answer 1

stores boot loaders.

Question 2

/proc

Answer 2

Stores system processes and resources.

Question 3

/sys

Answer 3

System ( helps with interacting with Linux kernel; everything runs in RAM and deletes on shutdown).

Question 4

/var

Answer 4

Stores files that grow in size like log files, databases for mail, etc.

Question 5

/usr

Answer 5

User applications; non-essential user applications are stored here.

Question 6

/lib

Answer 6

Libraries; files that binaries need to run certain application settings.

Question 7

/dev

Answer 7

Devices; hardware, KBMs, harddrives.

Question 8

/etc

Answer 8

Et cetera; all system-wide configuration files are here.

Question 9

/opt

Answer 9

Optional; manually installed software from vendors and some repositories(like zeek or suricata).

Question 10

/bin

Answer 10

Binaries; basic shell commands are stored here.

Question 11

/sbin

Answer 11

System Binaries; Binaries that a system admin would use.

Question 12

/home

Answer 12

All your personal files, documents, and downloads; user settings are also stored hidden files like .bashrc or .local.

Question 13

/media

Answer 13

Flash Drives; removable devices and drives.

Question 14

/mnt

Answer 14

mounted drives; permanent storage.

Question 15

/root

Answer 15

Root user’s home folder.

Question 16

/tmp

Answer 16

Stores system and user application data that is needed only temporarily.

Question 17

mkinitrd command

Answer 17

generates RAM disk files, initrd.img and initramfs.img that the bootloader uses to load the system kernel.

Question 18

grub2-install command

Answer 18

installs the grub2 configuration files to system.

Question 19

grub2-mkconfig command

Answer 19

generates a new grub.cfg config file that can be used to update existing grub.cfg file.

Question 20

grub2-update command

Answer 20

updates the grub2 configuration file.

Question 21

dracut command

Answer 21

predecessor of mkinitrd command. It will generate a generic initramfs image

Question 22

initrd.img

Answer 22

Archive file that contains all the essential files that are required for booting the OS.

Question 23

vmlinuz

Answer 23

The vmlinuz file is found in the boot directory and contains kernel code and data required to start and manage the system.

Question 24

GRUB2

Answer 24

Newer version of GRUB. It offers more control over the boot process, boot devices, and boot behavior.

The default bootloader today.

Question 25

Preboot eXecution Environment (PXE)

Answer 25

Allows the client to retrieve required boot loaders and system files from a server over the network.

Question 26

Kernel Panic

Answer 26

A critical error where the kernel has encountered an unrecoverable error. The system will halt and become unresponsive. This can happen because of bugs, hardware issues, bad drivers, filesystem corruption.

Question 27

Block devices

Answer 27

read/write in blocks of data (hard drives, SSDs).

Question 28

Character devices

Answer 28

Read/write in character streams of data (KBM, serial ports).

Question 29

/dev/null

Answer 29

A special type of virtual device that discards anything you send or redirect into it.

Question 30

/dev/zero

Answer 30

A special virtual device that returns a null character anytime you read from it. Sends back the ASCII character of 0x00.

Question 31

/dev/urandom

Answer 31

A special virtual device that returns a randomized series of pseudorandom numbers.

Question 32

./configure script

Answer 32

It is a script that will compile a configuration for software based on your system.

Question 33

make command

Answer 33

Once you make a configuration file with the ./configure script, this command will actually build the software from that configuration file.

Question 34

make install command

Answer 34

After using the ./configure and make command to configure and build out the software, the make install command will install these binaries to their appropriate locations.

Question 35

file storage

Answer 35

Organizes data into files and directories.

Question 36

Block storage

Answer 36

Divides data into fixed-size blocks that are accessed by their unique addresses.

Question 37

Object storage

Answer 37

Treats data as objects with unique identifiers, metadata, and content.

Question 38

Master Boot Record(MBR)

Answer 38

The sector that the BIOS reads in and starts when the machine is first booted

Question 39

GUID Partition Table (GPT)

Answer 39

Partition structure with a more modern design and is part of the UEFI standard.

Question 40

Filesystem in Userspace(FUSE)

Answer 40

This lets non-privileged users create their own file systems without editing the underlying kernel code.

Question 41

lspsi command

Answer 41

Displays info about devices connected to the system's PCI/PCIE buses.

Question 42

lsusb command

Answer 42

Used to list info about devices connected to usb. -v flag ----- device info bus -s ------ filter result -d ---- Vendor/product

Question 43

dmidecode command

Answer 43

Dumps the system's Desktop Management Interface table and presents it in a readable format.