Linux files structure

Question 1

What does -rw-r–r– mean?

Answer 1

• is it directory? (-/d)
• access rights for owner 3
• access rights for memebrs of files group 3
• access rights for everyone else 3

Question 2

What does second argument (1) mean?

-rw-r–r– 1 root root 1186219 2017-04-03 11:05 kubuntu-leaflet.png

Answer 2

Number of hard links

Question 3

Why are root args duplicated?

-rw-r–r– 1 root root 1186219 2017-04-03 11:05 kubuntu-leaflet.png

Answer 3

First is owner of file, second is name of group that own the file

Question 4

LESS command

1. Move to the end of file?
2. Move to the beggining of file?
3. Search for occurence of text?
4. Search for the next occurence of previous search?
5. See help for all LESS options?

Answer 4

1. Shift + g
2. g
3. /text + enter
4. n
5. h

Question 5

Simple copy paste trick?

Answer 5

Double click on a word in terminal, right click to paste it

Question 6

What is /bin directory?

Answer 6

Contains binaries used by system to boot and run

Question 7

What is /boot directory?

Answer 7

Contains linux kernel, RAM disk image, boot loader

/boot/vmlinuz is linux kernel

Question 8

What is /dev directory?

Answer 8

Contains device nodes.

Device is also a file for linux.

Question 9

What is /home directory?

Answer 9

base directory for each user.

Ordinary users should only have rights to modify files in home dirs

Question 10

What is /etc directory?

Answer 10

Contains system configuration files.
Also contains shell scripts, that start system services.

/etc/crontab defines automated cron jobs
/etc/fstab defines storage devices with their mount points
/etc/passwd contains list of user accounts

Question 11

What is /lib directory?

Answer 11

Contains shared library files by core system programs.

Similiar to windows DLL in Windows

Question 12

What is /lost+found directory?

Answer 12

Contains recovery data in case of failure of some device or formatted partition

Question 13

What is /media directory?

Answer 13

Contains mount points for removable media, like USB

Question 14

What is /mnt directory?

Answer 14

In Olders systems contains mount points for removable devices

Question 15

What is /opt directory?

Answer 15

Contains optional software, e.g. commercial programs

Question 16

What is /proc directory?

Answer 16

It is virtual file system maintained by kernel. Contains information how kernel sees computer.

Question 17

What is /root directory?

Answer 17

Home directory for root account

Question 18

What is /sbin directory?

Answer 18

Contains system binaries, reserved for superuser

Question 19

What is /tmp directory?

Answer 19

Storage of temporary files

Question 20

What is /usr directory?

Answer 20

Contains all program files used by regular users

Question 21

What is /usr/bin directory?

Answer 21

Contains executable programs installed by linux itself

Question 22

What is /usr/lib directory?

Answer 22

Contains shared libraries for /usr/bin dir

Question 23

What is /usr/local?

Answer 23

Initialy empty, contains programs for system wide usage

Question 24

What is /usr/sbin directory?

Answer 24

Contains more system administration programs

Question 25

What is /usr/share directory?

Answer 25

Contains all shared data used by programs in /usr/bin

Question 26

What is /usr/share/doc directory?

Answer 26

Documentation for most packages installed in system

Question 27

What is /var directory?

Answer 27

Contains data that is most likely to chane in time, e.g. database data, logs

Question 28

What is /var/log directory?

Answer 28

Contains log files of system activity Important files: /var/log/messages /var/log/syslog