Lesson 2: Managing Users and Groups

Question 1

echo (command)

Answer 1

Repeats input back to the user on the screen.

***commonly used to send information to the user in a script.

Question 2

ls (command)

Answer 2

Lists the contents of a directory. Can be given options to view permissions, hidden files, etc.

Question 3

pwd (command)

Answer 3

Displays the current working directory you are in.

Question 4

cd (command)

Answer 4

Changes your current working directory.

Question 5

touch (command)

Answer 5

Updates timestamp on an existing file, but can also be used to create an empty file.

Question 6

cp (command)

Answer 6

Copies a file or directory to another location.

Question 7

mkdir (command)

Answer 7

Creates a directory.

Question 8

cat (command)

Answer 8

is used to view the contents of a file without the option to edit that file.

Question 9

less (command)

Answer 9

is used to view the contents of a file when those contents won’t fit entirely on one screen. breaks the content output into pages that you can scroll through at the CLI

Question 10

vim

Answer 10

Starts a powerful text editorand the default for Linux.

Question 11

nano (command)

Answer 11

Starts a simple, user-friendly text editor. It may not be installed on all distros.

Question 12

gedit (command)

Answer 12

Starts a GUI text editor that is easy to use. Requires a desktop environment to be installed.

Question 13

su (command)

Answer 13

“substitute user” switches user credentials

The syntax of the su command is su [-] [user name]

Note: Without a user name argument, the su - command will assume you mean to lesign in as root.

Question 14

sudo (command)

Answer 14

Executes command as root

Password cached for five minutes by default

Question 15

su - (command)

Answer 15

Switches to root

Question 16

What command do we use to create a user account?

Answer 16

useradd

example: useradd jdoe

Or you can do something like useradd jdoe -c “John Doe” -e 2019/12/31 -s /bin/dash -d /home/john_doe

Question 17

What three commands will allow you to modify a user?

Answer 17

You can you userdel, usermod, or chsh

Question 18

Wsshat is the default password for the user?

Answer 18

There is no default password for user. One will have to be created using: passwd

Question 19

How can you view user defaults?

Answer 19

useradd -D

Question 20

What is the principle of least privilege?

Answer 20

users should be given no more authority on the system than they need to perform their job

Question 21

What command permits a user to edit a file with their own credentials, even if the file is only available to root user?

Answer 21

sudo edit

The syntax of the sudo edit command is sudo edit [options] {file name} -> sudo edit /path/to/file

Question 22

What is the wheel group?

Answer 22

Distributions allow administrative functions based on membership in the wheel group.Members of the wheel group exercise the administrative privileges of root with less potential for damaging the system.

Question 23

Which file allow you to configure a user with superuser privileges and how do you get to that file?

Answer 23

Enter visudo to open the /etc/sudoers file

Question 24

Whalesst file can you view all of the following “User name, Password, User ID, Group ID, Comment, Home directory and Login shell”?

Answer 24

The /etc/passwd file

Question 25

What command is used to control password expiration, expiration warnings, inactive days, and other information for existing accounts?

Answer 25

chage The syntax of the chage command is chage [options] {user name}

Question 26

What colsmmand creates a group?

Answer 26

groupadd The syntax of the groupadd command is groupadd [options] {group names}

Question 27

What command is used to change group's attributes?

Answer 27

groupmod The syntax of the groupmod command is groupmod [options] {group names}

Question 28

What command will delete groups from the /etc/group file?

Answer 28

groupdel The syntax of the groupdel command is groupdel [options] {group names}

Question 29

What does the whoami command used for?

Answer 29

Used to display the user name you are currently logged in to

Question 30

What does the # and $ characters represent?

Answer 30

For the root users it will show # & for standard users, the prompt will show a $ character

Question 31

What command determines the details of users currently logged in to a system?

Answer 31

The who command which includes the user name, the name of the system from which the user is connected, and the date and time that the user has been connected since. The syntax of the who command is who [options]

Question 32

What command displays the history of user login and logout actions, along with the actual time and date?

Answer 32

last The syntax of the last command is last [options]

Question 33

What command is used to display user ID (UID) and group ID (GID) information?

Answer 33

id The syntax of the id command is id [options] [user name]

Question 34

What is the .bashrc file?

Answer 34

File that enables customization of the user's own environment

Question 35

Where is the .bashrc file stored?

Answer 35

In a user's home directory

Question 36

What file provides shell configuration for the initial login environment?

Answer 36

The .bash_profile file note: the .bash_profile file is only read with the first login, while the .bashrc is read with all subsequent logins

Question 37

What is the w command primarily used for?

Answer 37

To display the details of users who are currently logged in to a system and their transactions. The syntax of the w command is w [options] [user name]

Question 38

What command displays the following information in order 1. status of the system, 2. table with the first column listing the users logged in to the system and lastly 3. indicating the current activities of the users?

Answer 38

The w command

Question 39

What file is delegation done in?

Answer 39

/etc/sudoers file can be done using the visudo editor

Question 40

What does each set of number represent in"17960:0:99999:7" & what is this a good indication of?

Answer 40

This is a good indication that a password has not been set for a user. 17960 = date password was stored (epoch format): 0 = minimum age: 99999 = maximum age: 7 = warning interval (days ahead of exp date you’ll get a warning)

Question 41

What is /etc/skel ?

Answer 41

A directory are automatically copied into the home directories of new users. * The contents of the /etc/skel directory are automatically copied into the home directories of new users. The account's home directory is populated using files from the /etc/skeldirectory.

Question 42

How would you maintain /etc/skel/ directories for new user accounts?

Answer 42

1. Assume superuser privileges 2. Enter cd /etc/skel 3. Enter vim .bash_profile 4. Make the necessary changes

Question 43

What is the /etc/passwd ?

Answer 43

A file that stores user all account information, default or user-specific.

Question 44

What is /etc/group ?

Answer 44

Is the storage location for groups. All groups, default or user-specific, will be found in this file.

Question 45

What are some commands to edit the /etc/group file?

Answer 45

The proper way to edit the /etc/group file is with the groupadd, groupmod,and groupdel commands.

Question 46

What is /etc/shadow?

Answer 46

This is a modern storage location for hashed passwords, as well as additional account information (stores details about User name, Password, Days since password changed, Days before password must be changed, Days until user is warned to change password, Days after password expires that account is disabled, Days the account has been disabled, Unused) note: only root has access to the content of the /etc/shadow file.

Question 47

What is /etc/profile ?

Answer 47

The /etc/profile file provides system-wide environment variables. This may be more effective for administrators to configure if there are settings that apply to all users.

Question 48

What is gpasswd -a command and option?

Answer 48

allow you to add user to group

Question 49

What is gpasswd -d command and option?

Answer 49

allow your to remove user from group

Question 50

What is gpasswd -A command and option?

Answer 50

allows you to add user as an admin of the group