LPI Linux Certification in a Nutshell, 2nd Edition

Administrative Tasks (Topic 1.111)

Review questions

1. Why is it considered insecure to store encrypted passwords in /etc/passwd?

   1. What is the alternative?

   2. When the alternative is implemented, what happens to the password field in /etc/passwd?

2. What would happen to a user account if the default shell were changed to /bin/false?

3. When a new account is created with useradd -m, what files are used to populate the new home directory?

4. Compare and contrast the execution of /etc/profile and /etc/bashrc.

5. What is the complete filename for the file where most syslog messages are sent?

6. Describe the three syslog parameters: facility, level, and action.

7. Compare and contrast cron and at.

8. Is there a cron command?

9. State the format of a crontab file, describing each of the six fields.

10. What does an asterisk mean in crontab fields 1 through 5?

11. Compare and contrast the differential and incremental backup methods.

12. Why is mt usually used along with tar to implement simple backup schemes?

    1. What special measures must be taken with regard to device names when using mt for multiple-volume tar backups?

Exercises

Exercise 1.111-1. User accounts

1. Examine the /etc/passwd file on your system.

   1. Is this the only means of user authentication on your system?

   2. Are shadow passwords in use?

2. Repeat the first exercise for groups.

3. If you have an expendable system available, experiment with implementing shadow passwords.

4. Add a user with useradd, including a new home directory populated with files from /etc/skel.

5. Add a group with groupadd.

6. Use usermod to ...