Command Line Crash Course

Question 1

What does “rm -rf /” do?

Answer 1

delete all contents of current file/app

never type this

Question 2

What does ‘pwd’ mean?

What does ‘pwd’ do?

Answer 2

• print working directory

- it prints path of current directory

Question 3

hostname

Answer 3

my computer’s network name

Question 4

mkdir

Answer 4

make directory

Question 5

cd

Answer 5

change directory

Question 6

ls

Answer 6

list contents of directory

Question 7

rmdir

Answer 7

remove directory

Question 8

pushd

Answer 8

push directory

Question 9

popd

Answer 9

pop directory

Question 10

cp

Answer 10

copy a file or directory

Question 11

mv

Answer 11

mv [current_name] [new_name]

move (or rename) a file or directory

Question 12

less

Answer 12

page through a file

Question 13

cat

Answer 13

print the whole file

Question 14

xargs

Answer 14

execute argument

Question 15

find

Answer 15

find files

Question 16

grep

Answer 16

find things inside files

Question 17

man

Answer 17

read a manual page

Question 18

apropos

Answer 18

find what man page is appropriate

Question 19

env

Answer 19

look at your environment

Question 20

echo

Answer 20

print some arguments

Question 21

export

Answer 21

export/set a new environment variable

Question 22

exit

Answer 22

exit the shell

Question 23

sudo

Answer 23

become super user root

DANGER! DANGER!

Question 24

chmod

Answer 24

change permission modifiers

Question 25

chown

Answer 25

change ownership

Question 26

What is bash?

Answer 26

• command line?

Question 27

alternate name for “directory”?

Answer 27

folder

Question 28

alternate name for “folder”?

Answer 28

directory

Question 29

Unix or Windows command prompt:

$

Answer 29

Unix

Question 30

Unix or Windows command prompt:

>

Answer 30

Windows

Question 31

name for directories inside directories?

Answer 31

path

Question 32

What is a path?

Answer 32

a name for directories inside directories;

a set of directions to the computer for where you want to put something in the tree of folders;

Question 33

What is the “graphical file browser” (or “graphical user interface”) on a Mac?

Answer 33

Finder

Question 34

What does “cd ..” do?

Answer 34

moves up one directory (to parent directory)

Question 35

What does “cd ../..” do?

Answer 35

moves up two directories (to parent’s parent directory)

Question 36

What does CLI mean?

Answer 36

Command Line Interface

Question 37

alternate names for CLI

Answer 37

terminal;
bash;
(command line) prompt;

Question 38

What does GUI mean?

Answer 38

Graphical User Interface

Question 39

move to root directory

Answer 39

cd /

Question 40

move to home directory

Answer 40

cd ~

Question 41

What is the “graphical file browser” or (“graphical user interface”) for Windows?

Answer 41

Windows Explorer

Question 42

What does ‘ls -1R’ do?

Answer 42

prints all sub-directories

Question 43

What does ‘mkdir -p’ do?

Answer 43

creates a directory path (even if directories in path haven’t yet been created)

Question 44

touch

Answer 44

create new file (in current directory)

Question 45

cp -r

Answer 45

cp -r [directory_name] [new_directory_name]
copy directory (and its contents) and create new_directory_name

Question 46

What does ‘rm -rf [directory]’ do?

Answer 46

removes specified directory and all of its contents

Question 47

What does ‘rm -r [directory]’ do?

Answer 47

removes specified directory (if it is empty)

- if directory is not empty, use ‘rm -rf [directory]’