FRP UNIX PAPER 2 SAMPLE QUESTION WITH ANSWERS

Sample Paper-2

1)The “kill -9 <PID>” command sends which of the following signals to the process?

a)INT

b)TERM

c)KILL

d)STOP

Answer: C.

2)If the STAT column of the output of the ps command shows that the process state of a given process is ‘S’, then which of the following is not true:

a)The process has been stopped or suspended from execution

b)The process is waiting for a resource

c)The kernel scheduler has pre-empted the process from execution because it has finished its allotted time slice

d)a & b

Answer: B.

Description: The process state of a suspended process is T;Process waiting for a resource moves to sleep state S;process pre-empted from kernel because it has run its time slice waits in the run queue, state is R

3)When a child process exits before the parent process exits, which of the following is true:

a)the child process becomes defunct

b)the process state for the parent process is shown as Z

c)if the parent process does not handle SIGCHLD, the child process becomes a zombie

d)none of the above

Answer: A.

4)A user does the following from the command line::

$ a.out &

[1] 8112

$ sh

$ a.out &

[1] 8216

$ ps

PID     TTY                 TIME              CMD

8001    tty1                  00:00:00          csh

8112    tty1                  00:00:00          a.out

8215    tty1                  00:00:00          sh

8216    tty1                  00:00:00          a.out

If the user executes the command “kill -9 8215”, then which of the following is true?

a)The a.out instance ( PID = 8216 ) is also terminated

b)a.out(PID=8216) becomes a defunct process

c)a.out(PID=8112) becomes a zombie, with parent as 8001

d)a.out(PID=8216) has parent process as 1

Answer: D.

 sh ( PID=8215) is the parent of a.out (PID=8216). Hence when sh is killed, init(PID=1) becomes parent of a.out (PID=8216)

5)which of these is NOT a valid variable in bash

a)__       (double underscore)

b)_1var    (underscore 1 var )

c)_var_    (underscore var underscore)

d)some-var (some hyphen var)

Answer:D.

Description: Hyphen's cant be used in variable name. It is encouraged to use meaningful variables instead of __ etc,though.  well, hyphen means subtract in appropriate context.

6)Assuming bash shell, what is the output of the following command:  

echo hello $0

a)hello echo

b)hello hello

c)hello bash

d)hello

Answer:C.

Description:"hello bash". The command is internally run in a forked bash & that bash itself is the zeroth argument.

Note, echo is just builtin command to shell Note. 

7)Assuming bash shell, what is the oputput of team=Unix  

echo 1.$team   2."$team"   3.'$team'   4.\$team

a)1.Unix   2.Unix   3.Unix    4.Unix

b)1.Unix   2.Unix   3.$team   4.$team

c)1.Unix   2.Unix   3.Unix    4.$team

d)1.Unix   2.$team   3.$team   4.$team

Answer: B.

8)Assuming bash shell, what is the return value ($?) after running this script :

team=Unix

[ $teamFCG = UnixFCG ] &&  exit 2

[ ${team}FCG = UnixFCG ] &&  exit 3

a)0

b)1

c)2

d)3 

Answer: D.

Description: $teamFCG does not evaluate since variable $teamFCG doesnt exits. since the first expression was FALSE, it does not execute the exit 2 (after &&).  ${team}FCG evaluates to UnixFCG, hence the script exits with 3 

9)which of these is/are the correct method for writing "foo" in /tmp/bar file?

1. echo foo > /tmp/bar

2. echo foo >> /tmp/bar

3. echo foo | /tmp/var

4. /tmp/bar < echo foo

a)1 & 2. 

b)all four amount to the same

c)1 and 3

d)3 and 4

Answer: A.

Description:  echo foo > /tmp/bar or echo foo >> /tmp/bar are correct

10)To have the errors from the output of a command displayed, which is the correct syntax?

a)command  3> &2

b)command  2> &1

c)command  2> 1&

d)command  2> /dev/null

Answer: B.