CIT 174

Week 4
Chapter 4 Review Questions
1. Describe the effect of including a hyphen when executing the su command. Using a hyphen after su allows you to assume the rights of another user.
2. A user’s primary group can be a User Private Group. True or False? Explain. True, for security reasons every new user has a private group with only one user. This is to prevent another user from accidently accessing someone else’s files.
3. The /etc/passwd file does not contain which of the following fields? (b) the file privileges for the user.
4. Explain the meaning of this line in the /etc/group file: “webmasters:x:710:rthomas,cyang”. Webmasters is the name of the group, x means the password is stored somewhere else, 710 is the group id (GID), and the two names are the members of the group.
5. To create or change a password on any user account, the following is used (c) the passwd command.
6. What does the fourth field in /etc/passwd contain? The group id or (GID) of the primary group for the user.
7. Why should you not use a standard text editor to add users to /etc/passwd? Because two people could be working on the file at the same time. In addition, a small typing error could make user accounts inaccessible.
8. If you enter a new password for a user that can be easily guessed, the message BAD PASSWORD appears and the password is (b) updated unless you are root. (I don’t like any of the choices!)
9. A mounted file system is one that (c) allows any user to run programs located on it.
10. The Shadow Password Suite enhances Linux security by (b) hiding encrypted passwords in a file that only root can read.
11. The df utility provides information about which one of the following (c) file system capacity, device name, and percentage used status.
12. If you attempt to unmount a mounted file system and receive an error message the most likely cause is (d) one or more users are working in a directory of the file system.
13. Describe the difference between an alias and a symbolic link. An alias causes the shell to substitute a different string than the one the user entered. Whereas a symbolic link causes the system to request a file from another place in the file structure.
14. Which command is used to create symbolic link? (b) ln.
15. The command chmod 744 report.doc grants (a) the user (the file’s owner) execute permission to the report.doc file.
16. The owner and group assigned to a file are shown by which of the following commands? (a) chown.
17. Execute permission on a file is required to(a) start that file as a program.
18. The tar command creates archive files that are most often compressed by the (d) gzip command.
19. The tar utility differs from the cpio utility in that (a) cpio always reads and writes to STDIN and STDOUT and tar uses command-line parameters.
20. Describe why the find command is often used with tar or cpio for backups. Because find can create a list of all the files that have been modified in the last day, which makes it easier to know what files to archive.
21. The (b) x option causes the tar command to extract the files from an archive file or device.
22. Describe how the newgrp command relates to the second field of each record in the /etc/group file. This is a rarely used command that allows a person who knows the group’s password to temporarily assume the group’s rights.
23. The output of the id command includes (a) the effective UID, the effective GID, and a list of groups of which the effective UID user is a member.
24. If the far left column in the output of the ls –l command shows the character “s” you would know that the object on that line was a (d) socket.
25. Which utility typically provides the highest compression ratio (makes the smallest compressed file from a given data file)? (b) bzip2.