Midterm Commands

Question 1

ls

Answer 1

List contents of a directory

Question 2

ls -al

Answer 2

List all contents of a directory, long style

Question 3

ls -alR

Answer 3

List all directory contents recursively

Question 4

pwd

Answer 4

Lists the present working directory

Question 5

cd

Answer 5

changes directory

Question 6

mkdir

Answer 6

makes a directory

Question 7

date

Answer 7

lists current date, time, and timezone

Question 8

echo $PATH

Answer 8

Prints to screen the path environment variable

Question 9

su

Answer 9

substitute user, super user, or switch user

Question 10

cat

Answer 10

displays a file on screen

Question 11

source

Answer 11

Evaluates a file or resource as a TCL script

Question 12

PATH

Answer 12

settings to change the environment variable PATH

Question 13

PS1

Answer 13

used in scripts to change a multitude of settings

Question 14

script

Answer 14

collection of commands stored in a file

Question 15

cp

Answer 15

copy

Question 16

ps

Answer 16

displays processes

Question 17

top

Answer 17

displays processes in real time

Question 18

file

Answer 18

determines file type

Question 19

kill

Answer 19

kills a process

Question 20

df

Answer 20

reports how much free disk space is available for each mount you have

Question 21

grep

Answer 21

searches a file for your search term

Question 22

free

Answer 22

displays memory usage

Question 23

ifconfig

Answer 23

displays network information

Question 24

cal

Answer 24

calendar for the year you specify

Question 25

history

Answer 25

lists all the commands you have used

Question 26

ps | awk ‘{print $4}’

Answer 26

pipes the process command into awk then prints the 4th column of the results

Question 27

set

Answer 27

read and write variables

Question 28

chmod

Answer 28

change access permissions of a file

Question 29

cat /proc/meminfo

Answer 29

displays memory usage in detail

Question 30

which

Answer 30

displays which executable is being run for your command

Question 31

touch

Answer 31

creates a file

Question 32

ln

Answer 32

creates a symbolic link (-s) or a hard link

Question 33

rm

Answer 33

removes file or directory

Question 34

dd

Answer 34

converts and copies a file, disk copy

Question 35

od

Answer 35

dumps files in octal and other formats

Question 36

more

Answer 36

displays more of a file

Question 37

man

Answer 37

manual pages

Question 38

whoami

Answer 38

displays current user

Question 39

dd if=/dev/zero of=/tmp/mynull count=1

Answer 39

dd command. copies the contents of device “zero” out to the file “mynull” in the /tmp directory.

Question 40

find

Answer 40

search for files in a directory hierarchy

Question 41

wc

Answer 41

print the number of bytes, words, and lines in files

Question 42

xargs

Answer 42

build and execute command lines from standard input