Sec. 30 User Account Management

Question 1

What is the user name

Answer 1

The unique name assigned to each user

Question 2

User password

Answer 2

The password assigned to each user

Question 3

User identification number(uid)

Answer 3

A unique number adorn to a user account.

Question 4

Group identification number (gid)

Answer 4

Indicates the primary, principal, or default group of the user

Question 5

What is the login shell

Answer 5

This shell is a program such as /bin/bash or bin/csh

Question 6

What utility would I use to create a user account?

Answer 6

useradd

Question 7

What utility t Gould I use to remove a user account?

Answer 7

userdel

Question 8

Name the utility that would allow me to change characteristics of an user account?

Answer 8

usermod

Question 9

Name the utility that would put an expiration date on a user’s password?

Answer 9

chage

Question 10

What utility allows me to change user passwords

Answer 10

passwd

Question 11

What is the format of chage?

Answer 11

chage [-m mindays] [-M maxdays] [-d lastday] [-I inactive] [-E expiredate] [- W warndays] user

Question 12

what does usermod -L do ?

Answer 12

lock the users account/password

Question 13

what does usermod -l NEW_LOGIN do?

Answer 13

the names of the user will be changed form login to NEW_LOGIN

Question 14

what does usermod -s SHELL do ?

Answer 14

the names of the user’s new login shell .

Question 15

what does the usermod -U do ?

Answer 15

unlocks the users password

Question 16

What is the format for the utility useradd ?

Answer 16

useradd [options] LOGIN

Question 17

what does useradd -c do?

Answer 17

allows comments to be added to the user information. Usually the users full name

Question 18

what does useradd -e EXPIRE_DATE do ?

Answer 18

it sets a date on which the account will be disabled

Question 19

how would I execute a command to force the user to change their password the next time they login?

Answer 19

$ sudo chage -d 0 USERNAME

Question 20

how would I invoke a restricted shell ?

Answer 20

bash -r

Question 21

What are some restrictions that a restricted shell enforce?

Answer 21

1. prevents user from changing directories 2. redirecting input and output

Question 22

what is ssh?

Answer 22

stands for secure shell , allows an admin to login through the network into a remote system.

Question 23

what does the command whoami do ?

Answer 23

returns the user name of the owner of the current login session.

Question 24

what command copies files between hosts on a network?

Answer 24

scp

Question 25

what is the for command ?

Answer 25

is a looping command.

Question 26

user-specifc configuration files are created under every user's home directory n the hidden what?

Answer 26

.ssh directory

Question 27

what command would show me the hidden .ssh directory ?

Answer 27

ls -la ~/.ssh

Question 28

what doe the file id\_rsa contain?

Answer 28

the user's private encryption key

Question 29

what does the file id\_rsa.pub contain ?

Answer 29

the user's public encryption key

Question 30

what file contains a list of public keys that are permitted to login?

Answer 30

authorized\_keys

Question 31

what file has a list of hosts from which logins have been allowed in the past?

Answer 31

known\_hosts

Question 32

what does the config file contain?

Answer 32

a configuration file for specifying various options

Question 33

what command will generate a user's private and public encryption keys ?

Answer 33

ssh-keygen

Question 34

the public key can be given to any machine with which you want to permit what?

Answer 34

password-less access

Question 35

If I were to invoke the following : **$ sudo useradd dexter** what UID would he receive?

Answer 35

the next available UID greater than **UID\_MIN** ( specified in **/etc/login.defs**) by defuat is assigned to dexter.

Question 36

If I were to invoke **$ sudo useradd dexter** what would be his first group ID?

Answer 36

A group called dexter with a GID=UID is also created and assigned as dexter's primary group.

Question 37

If I were to invoke **$ sudo useradd dexter** what home directory would dexter receive?

Answer 37

a home directory **/home/dexter** is created and owned by dexter.

Question 38

if the symbol **!!** or **!** is placed in the password field of the **/etc/shadow** file for an user's entry what would that indicate?

Answer 38

that the admin needs to assign the user a password for the account to be usable.

Question 39

If I were to invoke **$ sudo userdel morgan** what would happen to the home directory?

Answer 39

even though the account would be deleted. the home directory of the user would not be deleted.

Question 40

what option would I need to give to the command **userdel** to have the user's home directory deleted as well?

Answer 40

**-r**

Question 41

what can I use the command **usermod** for?

Answer 41

the command **usermod** can be used to **change chararcteristics** of the *_user account_*, such as ***group memberships**, **home directory,** **login name**, **password**, **default shell**, **user id** ,**etc...***

Question 42

what would be the result of the following command? ## Footnote **sudo usermod -L dexter**

Answer 42

dexter would be locked out of his account.

Question 43

if I would like to delete a user's account what command would i use?

Answer 43

**userdel**

Question 44

in the file **/etc/password** contains how many lines for each user?

Answer 44

one

Question 45

each item associated to an user in **/etc/password** is seperated by what?

Answer 45

**:** **semicolon**