Quiz 4 Review

1. CSI 135 Quiz 4 Review

2. 1 • 1) What Unix command will display information about your account only from the passwd file?

3. 1 • 1) What Unix command will display information about your account only from the passwd file? passwd –s awk –F: ‘{print $20}’ /etc/passwd whoami grep ^csi135b26 /etc/passwd grep –w ‘$USERNAME’ /etc/passwd grep $USER /etc/passwd grep ^csi135b26 /etc/passwd grep ^$USER /etc/passwd

4. 2 • 2) What Unix command will list the home directories for all of the students in this class?

5. 2 • 2) What Unix command will list the home directories for all of the students in this class? $ ls ~ / grep csi135b* $ grep ^csi135b /etc/passwd $ who $ cat /etc/passwd | grep ^csi135b $ awk –F: ‘{print $6}’ /etc/passwd $ ls $ ls /u/students/fall10/csi135 | grep b $ grep ^csi135b /etc/passwd | awk ‘{print $6}’

6. 3 • 3) What Unix command will list the files in your home directory in time order (i.e., with the most recently modified files listed last)?

7. 3 • 3) What Unix command will list the files in your home directory in time order (i.e., with the most recently modified files listed last)? $ ls -ltr

8. 4 • 4) Where should you add an alias to make sure it is available anytime you log in to a Unix system?

9. 4 • 4) Where should you add an alias to make sure it is available anytime you log in to a Unix system? • ~/.bash_profile • Or .bashrc

10. 5 • 5) If you add conflicting definitions for $MYBIN to the ends of your .bash_profile and .bashrc files on vader, which will be in effect when you’re fully logged in?

11. 5 • 5) If you add conflicting definitions for $MYBIN to the ends of your .bash_profile and .bashrc files on vader, which will be in effect when you’re fully logged in? • Those defined in .bash_profile

12. 6 • 6) If you forget your password on a Unix system, who can recover it for you?

13. 6 • 6) If you forget your password on a Unix system, who can recover it for you? • No one!

14. 7 • 7) What command will show you the last ten commands that you entered?

15. 7 • 7) What command will show you the last ten commands that you entered? • history • history | tail 10 • history 10

16. 8 • 8) What command will list your aliases?

17. 8 • 8) What command will list your aliases? • alias

18. 9 • 9) What command will show you how long a Unix system has been running (i.e., since its last reboot)?

19. 9 • 9) What command will show you how long a Unix system has been running (i.e., since its last reboot)? • w • uptime

20. 10 • 10) What does the command “chmodugo+x filename” do?

21. 10 • 10) What does the command “chmodugo+x filename” do? • Gives everyone execute permission to the file named filename

22. 11 • 11) How do you exit display of a man page?

23. 11 • 11) How do you exit display of a man page? • q

24. 12 • 12) What Unix command would you use to count the words (i.e., just the words) in the /etc/motd file?

25. 12 • 12) What Unix command would you use to count the words (i.e., just the words) in the /etc/motd file? • wc –w /etc/motd

26. 13 • 13) What Unix command will show you whether Apache is running on a Unix system?

27. 13 • 13) What Unix command will show you whether Apache is running on a Unix system? • ps –ef | grep apache • ps –ef | grep http

28. 14 • 14) What command will count the number of Apache processes running on a Unix system?

29. 14 • 14) What command will count the number of Apache processes running on a Unix system? • ps –ef | grep apache | wc -l

30. 15 • 15) Who can add files to the /tmp directory on vader?

31. 15 • 15) Who can add files to the /tmp directory on vader? • Everyone!

32. 16 • 16) What does the command ps -ef | awk '{print $1}' | sort | uniq –c do on a Unix system?

33. 16 • 16) What does the command ps -ef | awk '{print $1}' | sort | uniq –c do on a Unix system? Shows the number of processes being run by each user

34. 17 • 17) Write a Unix script that will loop through each argument provided

35. 17 • 17) Write a Unix script that will loop through each argument provided #!/bin/bash for n in $* do echo $n is a cool argument done

36. 17 • 17) Write a Unix script that will loop through each argument provided #!/bin/bash for n do echo $n is a cool argument done

37. 18 • 18) A case statement ends with what keyword?

38. 18 • 18) A case statement ends with what keyword? esac

39. 19 • 19) What error do you get if you mistype the shebang line in a bash script?

40. 19 • 19) What error do you get if you mistype the shebang line in a bash script? -bash: ./t1: /bin/bashy: bad interpreter: No such file or directory

41. 20 • 20) What does an exit command with an argument (e.g., exit 1) indicate?

42. 20 • 20) What does an exit command with an argument (e.g., exit 1) indicate? The script exited with some type of error condition

43. 21 • 21) What variable can be used to display the name of a script from within the script?

44. 21 • 21) What variable can be used to display the name of a script from within the script? $0

45. 22 • 22) What does x*) ls ~/bin;; do in a case statement? Explain the entire line.

46. 22 • 22) What does x*) ls ~/bin;; do in a case statement? Explain the entire line. If argument being evaluated starts with “x”, list the files in the user’s bin directory

47. 23 • 23) What commands might you use to prompt a user to enter a number and then read the number entered in a bash script?

48. 23 • 23) What commands might you use to prompt a user to enter a number and then read the number entered in a bash script? echo –n “please enter a number> “ read number

49. 24 • 24) What does an if command end with?

50. 24 • 24) What does an if command end with? fi