Bash MCQ Questions Answers

1. Which variable contains the process ID (PID) of the script while it's running?

2. In Bash, what does a # at the end of the default prompt string indicate?

3. Which statement will print all of the fully qualified .cvs files in the home directory or subdirectories while not displaying any errors?

4. To assign the command ls -lah to the shortcut command lh, what command should you use?

5. How can you copy a directory to another system with compression?

6. What are the results of the command with a user named jon? echo 'Hello, $(whoami)!'

7. To run a group of commands without spawning a subshell, which syntax would you use?

8. When comparing items with case, what statement indicates an end to the evaluation block?

9. Wich operator sends the output of ls to a file for later use?

10. How can you create a shared terminal in a Bash shell?

11. To make a Bash script named script.sh executable, what should you run?

12. Which sed options should you use to change the second-to-last instance of variable to rock so it would read: A constant is a variable that is a rock that isn't variable var="A constant is a variable that is a variable that isn't variable" echo "$var" | sed _____

13. Which does the below command do? w

14. Which one is true?

15. What statement would you use to print this in the console? Shall we play a game? yes\no

16. What is the output of this code? VAR="This old man came rolling" echo "${VAR//man/rolling}"

17. What does this command sequence do? cat >notes -

18. The shell looks at the contents of a particular variable to identify which programs it can run. What is the name of this variable?

19. What is the output of: VAR="This old man came rolling" echo "\${VAR//man/rolling}"

20. What does this command do? cat > notes -

21. In Bash, what does the comment below do? cd -

22. What does the + signify at the end of the 10-digit file permissions on data.txt? ls -l -rwx------+ 1 user1 u1 0 Oct 1 10:00 data.txt

23. When used from within a script, which variable contains the name of the script?

24. Which statement checks whether the variable num is greater than five?

25. When executing a command and passing the output of that command to another command, which character allows you to chain these commands together?

26. In order to write a script that iterates through the files in a directory, which of the following could you use?

27. How would you find the last copy command run in your history?

28. What will be the difference between the output on the screen and the contents of out.txt mysql < file.sql > out.txt

29. What will be in out.txt? ls nonexistentfile | grep "No such file" > out.txt

30. What file would match the code below? ls Hello[[.vertical-line.]]World

31. Which file allows you to save modifications to the shell environment across sessions?

32. What is the difference between the $@ and $* variables?

33. How can you gather history together for multiple terminals?

34. Which variable would you check to verify that the last command executed successfully?

35. What Bash script will correctly create these files?

36. What do you use in a case statement to tell Bash that you're done with a specific test?

37. What does this bash statement do? (( $a == $b ); echo $?

38. What would be in out.txt? cat < in.txt > out.txt

39. How could you get a list of all .html files in your tree?

40. Suppose your current working directory is your home directory. How could you run the script demo.sh that is located in your home directory? Find three correct answers. A. /home/demo.sh B. ./demo.sh C. ~/demo.sh D. bash /home/demo.sh E. bash demo.sh

41. What line of Bash script probably produced the output shown below? The date is: Sun Mar 24 12:30:06 CST 2019!

42. In order for a Bash script to be executed like an OS command, it should start with a shebang line. What does this look like?

43. If prompted for text at the standard input, you can tell the command you're done entering text with what key combination?

44. What is the output of this code? VAR="/var/www/html/website.com/html/"; echo "${VAR#*/html}"

45. How would you change your Bash shell prompt to the following? HAL>

46. What is the result of this script? txt=Penguins [[ $txt =~ [a-z]{8} ]]; echo $?

47. Which arithmetic expression will give the most precise answer?

48. What is the keyboard shortcut to call up the Bash history search as shown below? (reverse-i-search)`':

49. In order to extract text from the first column of file called textfile, which command would you use?

50. How does the SUID or setuid affect executable commands?

51. If file.sql holds SQL statements to be executed, what will be in file.txt? mysql < file.sql > file.txt

52. The _ keyword pauses the script to get input from standard input.

53. What happens if you use the "set -e" in a Bash script?

54. Assuming that user1 existed, what would be the result of this command string? awk -F: '/user1/{print $1 "-" $3 "-" $6}' /etc/passwd

55. To permanently remove empty lines from a file called textfile, which command could you use?

56. The command below will search the root filesystem for files named "finance.db". In this context, what information is being sent to /dev/null? find / -name "finance.db" 1>results.txt 2>/dev/null

57. Using "awk", what would the output of this command string be? echo "1 2 3" | awk '{for (i=1; i<=NF; i++) s=s+$i};END {print s}'

58. To run a copy command in a subshell, which syntax would you use?