linux commands

Question 1

pwd

Answer 1

Print the working directory you are in

Question 2

cd ..

Answer 2

return to the previous directory

Question 3

ls

Answer 3

list all files in the working directory

Question 4

ls –rtl

Answer 4

display detailed information about all files in the working directory and sort by their
modification time in ascending order

Question 5

ls –l

Answer 5

display detailed information about all files in the working directory

Question 6

cd

Answer 6

change the working directory to your home directory

Question 7

mkdir test

Answer 7

short for make directory. used to create directories on a file system

Question 8

rmdir test

Answer 8

short for make directory. used to create directories on a file system

Question 9

rmdir test

Answer 9

short for remove directory. used to remove/delete directories on a file system

Question 10

chmod [newpermission] [filenames]

Answer 10

u : user (yourself)
g: group
o: others (rest of the world)
a: all of the above (u, g and o)
-:remove this permission
+: add this permission
r: read access
w: write access
x: execute access

Question 11

chmod g-r test

Answer 11

remove read access form group

Question 12

chmod uog+rwx test

Answer 12

add read, write and excesute access to user, group and others

Question 13

who

Answer 13

get the information on curreclty logged in users

Question 14

ps -ef

Answer 14

see processes on the system. pipes the output to “less” to make it scrollable

Question 15

ps -fu user4

Answer 15

see processes on user 4 system

Question 16

finger

Answer 16

used to display information about local and remote users (similar to who)

Question 17

ifconfig -a:

Answer 17

display the status of all interfaces, even those that are down (show IP adress)

Question 18

kill -9 2168

Answer 18

the kill command is used to terminate processes without having to log out or reboot (restart) the computer. 2168 is the PID of the process

Question 19

PPID is

Answer 19

the parent process ID of PID

Question 20

definition od bash

Answer 20

the standard shell for common users (linux)

Question 21

korn shell

Answer 21

unix shell

Question 22

ksh

Answer 22

used to change execution method to ksh

Question 23

exit after ksh

Answer 23

used to exit ksh

Question 24

scripts

Answer 24

collection of commands that are stored in a file. the shell can read this file and act on the command as if they were typed at the keyboard

Question 25

vi test.sh

Answer 25

short for visual text editor. create test.sh (script) file, it is an interactive test editor.

Question 26

echo "hello world"

Answer 26

show hello world on the screen

Question 27

sleep 10

Answer 27

stop processes for 10 seconds

Question 28

./test.sh

Answer 28

to excute the script

Question 29

find . -name toto -print

Answer 29

automatically find the file's path by its name

Question 30

explane . in find . -name toto -print

Answer 30

start search from currect location

Question 31

explane toto in find . -name toto -print

Answer 31

name of the file is toto

Question 32

explane -print in find . -name toto -print

Answer 32

show the location (path) on the screen

Question 33

cd /etc etc:

Answer 33

location where there are files controlling the machines configuration like IP adress. It is one of the system directories.

Question 34

ls -rtl resolv.conf

Answer 34

get detailed information about resolv.conf only

Question 35

find / -name resolv.conf -print

Answer 35

search the entire machine for file "resolv.conf" and print the path on the screen (usually the system does not allow, therefore you must log in the root)

Question 36

find / -name resolv.conf -print | more

Answer 36

show the output in pages because ( | more ) is used

Question 37

find / -name \*\*ress\*\* -print

Answer 37

this command is used if you are trying to find a file that you only remember a few letters of those letters are put in this letters \*\* \*\* the stars indicate any letter

Question 38

find / -name \*\*ress\*\* -print \> toto

Answer 38

save the output of the search in file (toto). file toto is created automatically due to this command and the output is automatically in the file

Question 39

passwd

Answer 39

changes the password

Question 40

vi toto

Answer 40

opens a file

Question 41

:q

Answer 41

to exit

Question 42

dd

Answer 42

remove line

Question 43

4dd

Answer 43

removes 4 lines

Question 44

u

Answer 44

undo

Question 45

x

Answer 45

delete one character

Question 46

i

Answer 46

insertion mode

Question 47

a

Answer 47

insertion mode after the cursor

Question 48

o

Answer 48

write in a new line

Question 49

:w

Answer 49

save in memory

Question 50

shift g

Answer 50

go to the end of the file

Question 51

1 shift g

Answer 51

go to the begining of the file

Question 52

Print the working directory you are in

Answer 52

pwd

Question 53

return to the previous directory

Answer 53

cd ..

Question 54

list all files in the working directory

Answer 54

ls

Question 55

display detailed information about all files in the working directory and sort by their modification time in ascending order

Answer 55

ls –rtl

Question 56

display detailed information about all files in the working directory

Answer 56

ls –l

Question 57

change the working directory to your home directory

Answer 57

cd

Question 58

short for make directory. used to create directories on a file system

Answer 58

mkdir test

Question 59

short for make directory. used to create directories on a file system

Answer 59

rmdir test

Question 60

short for remove directory. used to remove/delete directories on a file system

Answer 60

rmdir test

Question 61

u : user (yourself) g: group o: others (rest of the world) a: all of the above (u, g and o) -:remove this permission +: add this permission r: read access w: write access x: execute access

Answer 61

chmod [newpermission] [filenames]

Question 62

remove read access form group

Answer 62

chmod g-r test

Question 63

add read, write and excesute access to user, group and others

Answer 63

chmod uog+rwx test

Question 64

get the information on curreclty logged in users

Answer 64

who

Question 65

see processes on the system. pipes the output to "less" to make it scrollable

Answer 65

ps -ef

Question 66

see processes on user 4 system

Answer 66

ps -fu user4

Question 67

used to display information about local and remote users (similar to who)

Answer 67

finger

Question 68

display the status of all interfaces, even those that are down (show IP adress)

Answer 68

ifconfig -a:

Question 69

the kill command is used to terminate processes without having to log out or reboot (restart) the computer. 2168 is the PID of the process

Answer 69

kill -9 2168

Question 70

the parent process ID of PID

Answer 70

PPID is

Question 71

the standard shell for common users (linux)

Answer 71

definition od bash

Question 72

unix shell

Answer 72

korn shell

Question 73

used to change execution method to ksh

Answer 73

ksh

Question 74

used to exit ksh

Answer 74

exit after ksh

Question 75

collection of commands that are stored in a file. the shell can read this file and act on the command as if they were typed at the keyboard

Answer 75

scripts

Question 76

short for visual text editor. create test.sh (script) file, it is an interactive test editor.

Answer 76

vi test.sh

Question 77

show hello world on the screen

Answer 77

echo "hello world"

Question 78

stop processes for 10 seconds

Answer 78

sleep 10

Question 79

to excute the script

Answer 79

./test.sh

Question 80

automatically find the file's path by its name

Answer 80

find . -name toto -print

Question 81

start search from currect location

Answer 81

explane . in find . -name toto -print

Question 82

name of the file is toto

Answer 82

explane toto in find . -name toto -print

Question 83

show the location (path) on the screen

Answer 83

explane -print in find . -name toto -print

Question 84

location where there are files controlling the machines configuration like IP adress. It is one of the system directories.

Answer 84

cd /etc etc:

Question 85

get detailed information about resolv.conf only

Answer 85

ls -rtl resolv.conf

Question 86

search the entire machine for file "resolv.conf" and print the path on the screen (usually the system does not allow, therefore you must log in the root)

Answer 86

find / -name resolv.conf -print

Question 87

show the output in pages because ( | more ) is used

Answer 87

find / -name resolv.conf -print | more

Question 88

this command is used if you are trying to find a file that you only remember a few letters of those letters are put in this letters \*\* \*\* the stars indicate any letter

Answer 88

find / -name \*\*ress\*\* -print

Question 89

save the output of the search in file (toto). file toto is created automatically due to this command and the output is automatically in the file

Answer 89

find / -name \*\*ress\*\* -print \> toto

Question 90

changes the password

Answer 90

passwd

Question 91

opens a file

Answer 91

vi toto

Question 92

to exit

Answer 92

:q

Question 93

remove line

Answer 93

dd

Question 94

removes 4 lines

Answer 94

4dd

Question 95

undo

Answer 95

u

Question 96

delete one character

Answer 96

x

Question 97

insertion mode

Answer 97

i

Question 98

insertion mode after the cursor

Answer 98

a

Question 99

write in a new line

Answer 99

o

Question 100

save in memory

Answer 100

:w

Question 101

go to the end of the file

Answer 101

shift g

Question 102

go to the begining of the file

Answer 102

1 shift g