Unix Calls

Question 1

ps -ef

Answer 1

Lists running processes
e (every process)
f (full output)

Question 2

fork

Answer 2

Creates new process that is clone of the parent process, returns pid of child

Question 3

execve

Answer 3

Executes program

Question 4

function > file

Answer 4

> is redirection of a command’s output to a file

Question 5

who

Answer 5

List of users currently logged on

Question 6

cat

Answer 6

Concatenates to single output

Question 7

exit

Answer 7

Normal process termination, exits current process

Question 8

kill

Answer 8

Kills processes that do not catch the signal

Question 9

init

Answer 9

First process started on boot, creates other processes (this is a daemon)

Question 10

grep

Answer 10

Prints all lines with the following expression in them

Question 11

thread_create

Answer 11

Library procedure that creates new thread

Question 12

thread_exit

Answer 12

Library procedure that causes thread to vanish such that it cannot be scheduled

Question 13

thread_wait

Answer 13

Library procedure that blocks the calling thread until a specific thread has exited

Question 14

thread_yield

Answer 14

Allows thread to voluntarily give up CPU time to another thread (there is no clock interrupt for threads, as there is for processes)

Question 15

select

Answer 15

Allows caller to tell if it will read or block

Question 16

access

Answer 16

System call to determine if access to file is available

Question 17

nice

Answer 17

change priority

Question 18

size

Answer 18

find out about size requirement

Question 19

exec

Answer 19

throws away current address space, replaces with current program

Question 20

wait

Answer 20

wait until child process exits, return PID of child and exit code

Question 21

stat

Answer 21

STATS AND SHIT

Question 22

chmod

Answer 22

change mode: rwx = 4,2,1
user (u), group (g), other (o), all (a)
eg. chmod u-r file.extension
or chmod a+rx file.extension

Question 23

lai

Answer 23

..

Question 24

ln

Answer 24

…27m link

Question 25

ls -l (ln?)

Answer 25

number between permissions and owner is link count

Question 26

ln -s

Answer 26

j

Question 27

man

Answer 27

files

Question 28

pipe

Answer 28

| creates pipe and returns 2 file descriptors: one for reading and one for writing

Question 29

curl

Answer 29

transfer data to/from server using supported protocol

Question 30

ping

Answer 30

test this

Question 31

trace

Answer 31

test this

Question 32

dig

Answer 32

..

Question 33

traceroute

Answer 33

...