Quiznetik

Operating System Architecture | Set 7

1. The statement z = ‘expr 5 / 2′ would store which of the following values in z?

Correct : C. 2

2. The expression expr -9 % 2 evaluates to:

Correct : C. -1

3. What is the output of the following program?b = [ -n $b ] echo $? [ -z $b ] echo $?

Correct : C. 0 0

4. What is the output of the following program? [ -n $HOME ] echo $? [ -z $HOME ] echo $?

Correct : A. 0 1

5. What is the output of the following program? x = 3; y = 5; z = 10; if [( $x -eq 3 ) -a ( $y -eq 5 -o $z -eq 10 )] then echo $x else echo $y fi

Correct : B. 3

6. What is the return value ($?) of this code:os = Unix [$osName = UnixName] && exit 2 [${os}Name = UnixName] && exit 3

Correct : D. 3

7. What is the output of the following code: s=Unix echo 1.$os 2."$os" 3.'$os' 4.$os

Correct : B. 1.unix 2.unix 3.$os 4.unix

8. which of these is NOT a valid variable in bash

Correct : D. some-var (some hyphen var)

9. What will be output of following command:$ echo "The process id is" $$$$

Correct : C. the process id is <pid><pid>

10. What would be the current working directory at the end of the following command sequence? $ pwd /home/user1/proj $ cd src $ cd generic $ cd . $ pwd

Correct : D. /home/user1/proj /src/generic

11. How do you print the lines between 5 and 10, both inclusive

Correct : A. cat filename | head | tail 6

12. Create a new file “new.txt” that is a concatenation of “file1.txt” and “file2.txt”

Correct : B. cat file1.txt file2.txt > new.txt

13. If a file with execute permissions set, but with unknown file format is executed

Correct : C. the current shell will try to execute it

14. Which of the following is true?

Correct : C. shell is a wrapper for all the commands and utilities

15. Which is true with regards to the shell prompt

Correct : C. the prompt can be customized (modified)

16. What is a shell in UNIX?

Correct : A. a program through which users can issue commands to unix

17. Which of the following represents an absolute path?

Correct : D. /usr/bin/cat

18. The user bhojas logged in and performed the following sequence of command. What will be the output of the last command? $ cd project/module1 $ pwd

Correct : A. /home/bhojas/project/m odule1

19. BASH shell stands for?

Correct : A. bourne-again shell

20. Which of the following files will not be displayed by the command cat re* ?

Correct : C. receipt

21. The redirection 2> abc implies

Correct : C. write standard error to abc

22. cmd 2>&1 > abc will

Correct : D. write standard output to abc & standard error to monitor

23. cmd > abc 2>&1 will

Correct : B. write standard output and standard error to abc

24. Which of these is the correct method for appending “foo” in /tmp/bar file?

Correct : B. echo foo >> /tmp/bar

25. Syntax to suppress the display of command error to monitor?

Correct : D. command 2> /dev/null

26. The following commands gives the output like this #cat file1 file2 #cat: file1: No such file or directory hello If we execute the command “cat file1 file2 1>2 2>&1” the output would be

Correct : B. no output is displayed

27. cat < file1 >> file2 | file3

Correct : D. syntax error

28. Executing cat /etc/password > /dev/sda as superuser will

Correct : B. write data to the physical device sda

29. rom where would the read statement read if the following statements were executed? exec < file1 exec < file2 exec < file3 read line

Correct : B. it would not read any files