L+ Users and groups/

Group ID

unique number of a user's primary group membership

user id

unique number that represents the user to the system

Passwd command

used by the root user to set or reset a password

Who

used to determine the details of the users currently logged in username Name of the system Date and Time in that order

W command

used to display the details of users that are currently logged in to a system and their transactions

ID

used to display user ID (UID) and group ID (GID) information Entering no options displays information about the user who is currently logged in id (options) (username)

Group name

user friendly name of the group

What is a Standard User

user that runs applications, configures databases, and creates webistes To ensure system security, user accounts should not be shared

How do you create a user in Linux command line

useradd Example useradd (options) (username) Account is stored in /etc/passwd file Configured according to options set in the /etc/login,defs file Home directory

What are some nuances of useradd

Account is stored in /etc/passwd file Configured according to options set in the /etc/login.defs file Home directory is created in the /home/ <account anme> Directory and populated using files from the /etc/skel/ directory

Service

Accounts that are specific to the service (HTTP for web service or mysql for database service Service accounts run in the background and perform a single function

What can root user accounts do?

Administrative tasks Password Resets System Config User Account management

Lines of input after W command

First Line of output -Displays the status of the system Second line of output Displays a table column list of the users logged in to the system Third line of output - Last column Indicates the current activities of the users W (options) *Username

First terminal user details

Last 1 The last command retrieves information from the /var/log/wtmp file Last (options)

/etc/profile file

provides system-wide environment variables that are sued to apply certain settings to user accounts -/.bash_profile -/.bash_login -/.profile

bash_profile file

provides the shell configuration for the inital login environment Bash_profile File /etc/skel When a new user account is created in /etc/skel directory, it is automatically copied into the new user's home directory Files added to the /etc/skel/ directory after a user account is created will not be copied to existing users; home directories

Group ID

reference number on the system

Login shell

shell that is launched when user logs in (/bin/bash or /bin/ksh) useradd usermod userdel

/etc/group

storage location for all groups

What command allows you to switch user credentials to the root user

su-root

Visudo

verifies /etc/sudoers syntax before committing changes -c (check file error) -f (edit/check location -s (Check files in strict mode) -x (output in JSON) Wheel group members exercise root privileges with less potential for damaging the system

/etc/bashrc

provides system-wide configuration changes specific to bash settings

useradd command does not set a password for the account

-c comment field -e expiration date -s (default shell of the user) . useradd -s/bin/ksh -d (view default config for new users)

What are some options for the who command

-u (idle time) . (active user Old (inactive over 24hrs) Am i (who amd I) gives you user info

.Bashrc file

enables customization of the user's own environment Adapt to specific needs and preferences Create environment variable Set default directories and file permissions Change default command prompt

Sudo command

enables the server admin to delegate commands to users

How do you delegate a user account

List the user in the /etc/sudoers file using the visudo editor to delegate the user account

/etc/shadow

Modern storage location for hashed passwords and additional account information Only root has access to the /etc/shadow file

Will groupdel delete user accounts within a group?

NO Groupdel will only delete the group itself

Polkit Command

Pke xec Example Pkexec Mkdir /Jason

Account Profiles

Profiles for accounts

Group list

Refers to members of the group

comment

Represents full name of the user

What is Root

Root is the superuser account in Linux. IT typically has the highest access rights on the system However in Unix and Linux ay account with user ID - is a root account.

What command allows you to Substitue or Switch a user

SU

/etc/profile.d

Serves as storage location for scripts that admins may use to set additional system-wide variables Set tje emvornment variables via scripts contained in /etc/profile,d

Polkit or Sudo?

Sudo, Sudo is easier to use more flexible and has better security thatn pkexec

Least Privilege

The practice of giving users only as much access as needed to perform certain job functions

What does the whoami command do?

Used to display the username currently logged in to the system

What is Superuser (ROOT)

User with admin credentials Always log into a system with a non privileged user account

What are the fields of information in the (/etc/shadow) file

Username Password (hashed format) Days since password was changed Days before password must be changed Days until user is warned to change password Days after password expires that account gets disabled Days the account has been disabled Unused field that is reserved for future use /etc/passwd /etc/shadow

How do you verify the current username on a system

Whoami command If the user is a toot user beside their name will be a # If the user is a standard user beside their name will be a $

Can users be members of more than one group

Yes Users can be apart of three groups Administrator Group Instructor Group Accounting Group

groupmod

command to change the group's attributes

groupadd

command to create a group

groupdel

command to delete groups

password

contains assigned password to the user

username

contains the name the user use to log into the system

Polkit (PoliciyKit)

controls system wide privileges that allows non - privileged processes to communicate with privileged ones

Last

displays the history of user login and logout actions and the actual time and date

How do you change the name of a group using groupmod

group mod (options) (group names)

If you want to create a group and exit if it exists. which group option should you pick

groupadd -f

If you want to create a group what should your group/option tree be

groupadd -g

How do you create a group with a specified group name

groupadd -g instuctors groupadd (options) (group names)

How do you create a group with a non-unique group ID

groupadd -o

How do you change a group's ID

groupmod -g

How do you rename a group

groupmod -n

Superuser

highly privileged accounts primarily used for administration by specialized IT employees. These users/accounts may have virtually unlimited privileges, or ownership, over a system. Superuser account privileges may allow: full read/write/ execute privileges. creating or installing files or ...

Password

password required to enter the group

Home directory

path to the home directory of the user

Sudoedit

permits a user to edit a file with own credentials %editors ALL = sudoedit /path/to./file Do not edit /etc/sudoers with standard text editros like Vi(m), nano, or gedit