linux commands

Question 1

what does the kernel on UNIX do?

Answer 1

it is the hub of the op system - ALLOCATES TIME + MEMORY TO PROGRAMS -
also handles filestore + comms in response to system calls

Question 2

what does the shell do on UNIX do?

Answer 2

acts as interface between user + kernel

Question 3

to list personal files and subdirectories

Answer 3

ls

Question 4

ls doesnt always list everything, just those not prefixed with a dot (HIDDEN FILES). how do you make a list inclusive of these

Answer 4

ls -a

Question 5

how to display username

Answer 5

whoami

Question 6

how to make directory

Answer 6

mkdir dirname

Question 7

how to change directory

Answer 7

dc dirname

Question 8

how to stay in directory you are in

Answer 8

cd .

Question 9

how to navigate to parent directory

Answer 9

cd ..

Question 10

pathnames enable you to work out where you are in file system. how do you print this out?

Answer 10

pwd

Question 11

home directories can also be referred to by tilde character - can be used to specify paths starting at home directory

Answer 11

ls ~/dirname

Question 12

how to copy file

Answer 12

cp file1 file2

Question 13

how to create a file

Answer 13

touch filename

Question 14

how to create backup

Answer 14

rename filename.txt to filename.bak

Question 15

how to move/rename file

Answer 15

mv file1 file2

Question 16

how to remove a file

Answer 16

rm filename

Question 17

how to remove a directory

Answer 17

rmdir directoryname

Question 18

to clear screen

Answer 18

clear

Question 19

what does the command cat (concatenate) do?

Answer 19

displays contents of file to screen

Question 20

what does the head command do?

Answer 20

displays first 10 lines of file to screen

Question 21

what effect will typing in -5 do to head command?

Answer 21

deducts last 5 lines from the 10 displayed

Question 22

what does tail command do?

Answer 22

displays last 10 lines of files

Question 23

what does grep do? specify the syntax

Answer 23

displays a specified word from the file to screen. grep science science.txt

Question 24

what option is used to ignore uppercase and lowercase letters?

Answer 24

grep -i science science.txt

Question 25

what syntax is used to search for a specific phrase?

Answer 25

grep -i ‘spinning top’ science.txt

Question 26

what are the other options of grep and their meanings?

Answer 26

-v display those lines that do not match
-n precede each matching line with line number
-c print only total count of matched lines

Question 27

what syntax is used to perform a word count?

Answer 27

wc -w science.txt

Question 28

what syntax is used to perform a line count?

Answer 28

wc -l science.txt

Question 29

how to write contents to a file

Answer 29

cat > list1
pear
banana
apple
^D

Question 30

how to read the contents of a file

Answer 30

cat list1