UNIX COMMANDS

Question 1

cp -r arg1 arg2

Answer 1

copy content of arg1 directory to the arg2 directory.

Question 2

man command

Answer 2

will print the manual for using a specific command.

Question 3

cd

Answer 3

change directory.

Question 4

cd /

Answer 4

go to root directory.

Question 5

cd ~

Answer 5

go to home directory.

Question 6

cd ..

Answer 6

navigate one directory up.

Question 7

cd ./arg1/arg2

Answer 7

navigate into arg2 directory which is inside arg1 directory.

Question 8

ls

Answer 8

allows us to see the contents of the current directory.

Question 9

ls -a

Answer 9

allows you to see hidden items in a directory.

Question 10

ls arg1

Answer 10

allows us to see the contents in the arg1 directory.

Question 11

mkdir

Answer 11

allows us to create a new directory.

Question 12

pwd

Answer 12

prints the directory you’re currently working in.

Question 13

echo

Answer 13

command that will print a string or the result of a command to the console.

Question 14

touch

Answer 14

creates a file but also allows you to modify the timestamp of a file. (Usually used to create empty files).

Question 15

cat > filename

Answer 15

creates a new file

Question 16

cat filename

Answer 16

Displays the file content

Question 17

mv file “new file path”

Answer 17

moves the files to the new location

Question 18

mv filename new_file_name

Answer 18

Renames the file to a new filename.

Question 19

rm filename

Answer 19

Deletes a file.

Question 20

clear

Answer 20

clears the terminal

Question 21

rmdir

Answer 21

Deletes a directory.

Question 22

mkdir directoryname

Answer 22

creates a new directory in the present working directory or at the specified path.

Question 23

grep

Answer 23

prints any lines in a file or files that match a given pattern.

Question 24

rm

Answer 24

will remove a file.

Question 25

ln

Answer 25

creates a link between files. Allow you to make a shortcut to a file.

Question 26

wc

Answer 26

will print the number of words in a file.

Question 27

rm -r arg1

Answer 27

removes arg1 directory.

Question 28

chmod

Answer 28

change permissions on a file

Question 29

chmod 754 hello.txt does what?

Answer 29

owner has read, write, and execute.

groups have read and execute.

others have read.

Question 31

$USER

Answer 31

Gives current user’s name.

Question 32

$PATH

Answer 32

Gives search path for commands.

Question 33

$PWD

Answer 33

Gives the path of present working directory.

Question 34

$HOME

Answer 34

Gives path of home directory.

Question 35

$HOSTNAME

Answer 35

Gives name of the host.

Question 36

$LANG

Answer 36

Gives the default system language.

Question 37

$EDITOR

Answer 37

Gives default file editor.

Question 38

$UID

Answer 38

Gives uer ID of current user.

Question 39

$SHELL

Answer 39

Gives location of current user’s shell program.

Question 40

What is Amazon EC2?

Answer 40

A virual computing environment.