Command Line

Question 1

. command

Answer 1

current directory

Question 2

.. command

Answer 2

previous directory

Question 3

What is “" used for?

Answer 3

To escape a character

Question 4

ls command

Answer 4

list the current filesystem

Question 5

mv command

Answer 5

move a file

Question 6

cp command

Answer 6

copy a file

Question 7

what’s the difference between starting a filesystem with or without a “/”?

Answer 7

a starting / means it is an absolute path; not starting with one means a relative path

Question 8

rm command

Answer 8

remove something

Question 9

*

Answer 9

wildcard operator that matches any number of characters

Question 11

-r

Answer 11

recursive option

Question 12

find command

Answer 12

search for things

Question 13

man command

Answer 13

brings up the manual

Question 14

su command

Answer 14

substitute user: su <username> <password></password></username>

Question 15

normal user privileges

Answer 15

can modify own stuff. can’t modify system stuff

Question 16

root user privileges

Answer 16

You can modify anything. It is usually disabled

Question 17

sudo command

Answer 17

briefly take command as a root user

Question 18

why do file permissions have 9 slots?

Answer 18

3 groups of 3 permissions each. The groups are the current user, the group, and others. the type of permissions are read, write, and execute.

Question 19

file permissions execute?

Answer 19

you can run the file as program

Question 20

chmod command

Answer 20

changes the permission mode string

Question 21

chown command

Answer 21

change the files owner

Question 22

chgrp command

Answer 22

change the file’s group

Question 23

how does octal file permission work?

Answer 23

each permission has a number: read: 4, write: 2, execute: 1. You add them all together ie if you have all permissions for user, you get 7. if you only have 5, you get read and execute. you will get a three digit number because you do permissions for user, group, and others all at once.

Question 24

How does symbolic file permission work?

Answer 24

user, group, and others are represented by u, g, and o. Read, write and execute are represented by r, w, and x. To add a permission, you get the person (u g o) and use the plus symbol. You can subtract a permission with minus. You can set a permission with equals. You can also change all permissions at once with a instead of u, g, or o.

Question 25

cat command

Answer 25

see the contents of a file

Question 26

touch command

Answer 26

make a file

Question 27

stat command

Answer 27

see a lot of information for a file

Question 28

nano command

Answer 28

lets you edit a file

Question 29

What is a link?

Answer 29

links are files that reference other files. they are pointers so you don’t need the file in multiple places

Question 30

What are the two types of links

Answer 30

hard and soft links

Question 31

ln command

Answer 31

makes a hard link.

Question 32

ln -s command

Answer 32

makes a soft link

Question 33

what is the pipe command?

Answer 33

|

Question 34

echo command

Answer 34

it prints out what you say

Question 35

What does pipe do?

Answer 35

lets you send your command to something else

Question 36

head command

Answer 36

see the beginning of a file

Question 37

tail command

Answer 37

see the end of a file

Question 38

less command

Answer 38

displays text one page or screenful at a time and provides navigation controls

Question 39

grep command

Answer 39

searches inside files according to a pattern, can be regex

Question 40

awk command

Answer 40

extracts specific text from a file

Question 41

sed command

Answer 41

is a stream editor

Question 42

rev command

Answer 42

prints text in reverse sequence

Question 43

tac command

Answer 43

concatenates or displays files in reverse

Question 44

tr command

Answer 44

translates or modifies individual characters according to parameters

Question 45

tar command

Answer 45

tape archive to bundle groups of files. Can also apply compression with an option

Question 46

tar -x command

Answer 46

extract a file