Command Line

Question 1

od

Answer 1

display file content’s in octal

Question 2

nl

Answer 2

number lines in text file

Question 3

sort

Answer 3

sorts in alphabetic order

Question 4

sort -n

Answer 4

sort in numerical order

Question 5

less

Answer 5

pager utility lets you move through file one page at a time, more flexible than more

Question 6

head

Answer 6

lists top ten lines of text file

Question 7

tail

Answer 7

shows last ten lines of text file

Question 8

wc

Answer 8

displays file lines, words, and bytes

Question 9

uniq

Answer 9

finds repeat lines in a text file

Question 10

md5sum

Answer 10

can check a files integrity

Question 11

name the secure hash algorithms

Answer 11

sha224sum, sha256sum, sha384sum, sha512sum

Question 12

secure hash algorithms

Answer 12

can be used to check file integrity, generally used for cryptography

Question 13

grep

Answer 13

filters text files

Question 14

STDOUT

Answer 14

directs output to terminal

Question 15

>

Answer 15

sends the command’s output

Question 16

> >

Answer 16

appends data to preexisting file

Question 17

The file descriptor that identifies a command or script file error is

Answer 17

2

Question 18

how do you make grep use extended regular expressions (ERE)?

Answer 18

grep -E or egrep

Question 19

The file descriptor that identifies output from a command or script file is

Answer 19

1

Question 20

STDERR

Answer 20

identifies a command or script file error

Question 21

The file descriptor that identifies an input into a command or script is

Answer 21

0

Question 22

STDIN

Answer 22

identifies an input into a command or script

Question 23

2>

Answer 23

redirect STDERR to a specified file.

Question 24

2»

Answer 24

redirect STDERR to the specified file. (append)

Question 25

&>

Answer 25

redirect STDOUT and STDERR to the specified file

Question 26

&>>

Answer 26

redirect STDOUT and STDERR to the specified file (append)

Answer 27

redirect STDIN from the specified file into the command

Question 28

<>

Answer 28

redirect STDIN from the specified file into command and redirect STDOUT to the specified file

Question 29

where is the password file

Answer 29

/etc/passwd

Question 30

|

Answer 30

redirect STDOUT, STDIN, and STDERR between multiple commands

Question 31

sed

Answer 31

stream editor

Question 32

stream editor

Answer 32

modifies text that is passed to it via a file or output from a pipeline

Question 33

echo "I like cake." | sed 's/cake/donuts'

Answer 33

I like donuts

Question 34

echo "I love cake and more cake." | sed 's/cake/donuts/g'

Answer 34

I love donuts and more donuts.

Question 35

watch

Answer 35

use it to enact a command over and over again

Question 36

placing an & after a command does what?

Answer 36

runs it in the background

Question 37

sleep

Answer 37

used for adding a pause in a shell script.

Question 38

how do you specify the number of seconds for sleep to run?

Answer 38

sleep n

Question 39

jobs

Answer 39

allows you to see any processes that belong to you that you are running

Question 40

how do you return a program to the foreground?

Answer 40

fg %[job number]

Question 41

jobs -l

Answer 41

lists jobs

Question 42

Ctrl+Z

Answer 42

pauses a process

Question 43

how do you send a program to the background?

Answer 43

bg %[job number]

Question 44

what is the syntax to stop a job in the background with the kill command?

Answer 44

kill %[job number]

Question 45

what command keeps a job running after logout?

Answer 45

nohup [command] &