Creating Linux Users is (TOO?) Easy!

Summary

This video demonstrates how to create, delete, and modify users on a Linux system using command-line tools. The speaker explains the importance of using these tools instead of manually editing files like the password file, as errors could lock everyone out of the system. Through practical examples, the video shows how to add users, set home directories, assign groups, and prepopulate home directories with files. It also covers how to modify user groups and assign passwords, emphasizing the ease and safety of using built-in Linux commands.

Takeaways

• 😀 Being a system administrator can seem boring, but it’s an important role.
• 👤 The video demonstrates how to create, delete, and modify users on a Linux system.
• 🔧 Using the command line is an efficient way to manage users, avoiding manual file edits.
• 🏠 You can specify a user’s home directory with the `-d` flag when adding a user.
• 👥 Supplementary groups can be added with the `-G` flag to assign users to multiple groups.
• 📂 The `-m` flag ensures the creation of a user’s home directory with the correct permissions.
• 🛠 The `useradd` and `usermod` commands are essential for managing user groups and permissions.
• 📝 The video covers how to preload a user’s home directory with default files using the `/etc/skel` folder.
• 🚫 The `userdel` command helps remove a user and their associated files from the system.
• 🔑 Setting a password for a new user is done using the `passwd` command, making sure the user can log in.

Q & A

What is the main purpose of the video?

The video aims to demonstrate how to create, delete, and modify users on a Linux system using command-line tools.

Why does the presenter recommend using command-line tools instead of manually editing system files?

The presenter recommends using command-line tools because manually editing system files like the password file can lead to errors, such as permission issues or typos, that might lock users out of the system.

Which command does the presenter use to add a new user in the system?

The presenter uses the `sudo useradd` command with various options like `-d` for specifying the home directory, `-m` to create the directory, and `-G` to assign supplementary groups.

What is the importance of the `-m` option when creating a user?

The `-m` option ensures that the user’s home directory is created with the appropriate permissions and ownership when the user is added.

How does the presenter add a user to supplementary groups?

The presenter uses the `sudo usermod -aG` command to append a user to supplementary groups without removing the user from existing groups.

What is the skeleton directory (`/etc/skel`) used for?

The skeleton directory (`/etc/skel`) is used to prepopulate a user's home directory with default files and settings when the user is created.

How can you assign a password to a newly created user?

You can assign a password to a newly created user using the `sudo passwd <username>` command, which prompts you to enter the new password for the user.

What happens if you forget to include the `-a` option when using `usermod` to add a user to a group?

If the `-a` option is omitted, the user will be removed from all their existing supplementary groups and will only belong to the new group specified, which could unintentionally revoke access to certain privileges.

How can you remove a user and their home directory from the system?

You can remove a user and their home directory using the `sudo userdel -r <username>` command, where `-r` ensures the user’s home directory and mail spool are also deleted.

Why does the presenter advise against modifying the password file manually?

Modifying the password file manually can lead to mistakes that might corrupt the file or result in login issues, making it safer to use dedicated command-line tools.

Outlines

00:00

💻 Apology and Introduction to Linux User Management

The speaker begins by apologizing for the video and admitting that being a system administrator can be boring. They also humorously mention feeling lonely, leading to the creation of the video. The main topic is user management in Linux, particularly creating, deleting, and modifying users using command line tools instead of manually editing files like the password file. This introduction sets the stage for a tutorial on Linux user management.

05:01

🔧 Introduction to Adding a New User in Linux

The speaker explains the basics of using the `useradd` command to create new users on a Linux system. They stress the importance of specifying certain parameters, such as the home directory and supplementary groups, to ensure proper user creation. Using the example of creating a user named 'Susie,' the speaker demonstrates how to assign Susie to specific groups and ensure her home directory is created correctly. They also emphasize the importance of using `-m` to create the home directory and avoid mistakes.

10:02

🛠 Modifying User Groups and Commands in Linux

The speaker delves into the `usermod` command, focusing on how to modify existing users by appending them to additional groups without overwriting their current group memberships. The speaker demonstrates how to add Susie to a newly created group called 'cool people' and explains the significance of using the `-a` (append) option when modifying groups. This ensures that users remain part of their original groups while being added to new ones.

📂 Populating User Directories with Default Files

The speaker introduces the 'skeleton directory' (`/etc/skel`), which is used to pre-populate a new user’s home directory with default files. They demonstrate this by creating a file in `/etc/skel` and showing that this file appears automatically in Susie's home directory after her account is created. The tutorial concludes with a command for deleting users (`userdel`) and emphasizes the importance of properly managing user files and permissions.

🔒 Assigning and Changing User Passwords

In this section, the speaker explains how to assign a password to a new user using the `passwd` command. They illustrate this by assigning Susie a password, demonstrating how to log in as Susie using SSH, and verifying that the new user has access to their home directory. The speaker highlights the importance of setting strong passwords and ensuring user account security.

🚫 Safely Deleting Users and Preventing System Errors

The final segment emphasizes the importance of using command line tools for managing users rather than manually editing system files like `/etc/passwd`, which could cause severe issues if handled improperly. The speaker summarizes the key points about user management and closes the video with a reminder to learn, enjoy what you do, and be kind.

Keywords

💡System Administrator

A system administrator is responsible for managing and maintaining computer systems, particularly servers and networks. In the video, the speaker jokes about the role being 'quite boring,' but then demonstrates how tasks such as creating and managing users are important responsibilities for administrators.

💡User Creation

User creation refers to the process of setting up a new account on a Linux system, allowing a person to log in and access system resources. In the video, the speaker shows how to create a user named 'Susie' using the 'useradd' command, including steps to assign her a home directory and add her to administrative groups.

💡Home Directory

The home directory is a dedicated folder where a user's files are stored on a system. When creating a user like 'Susie,' the video emphasizes specifying and creating her home directory using the '-d' and '-m' flags to ensure proper setup and permissions for the new user.

💡Supplementary Groups

Supplementary groups are additional groups a user belongs to, which grant access to specific system resources or permissions. The speaker adds 'Susie' to the 'sudo' and 'adm' groups, allowing her to perform administrative tasks on the system. This is done using the '-G' flag in the 'useradd' command.

💡Command Line Tools

Command line tools refer to programs that are run in the terminal, often without a graphical user interface. The video highlights how these tools, like 'useradd' and 'usermod,' simplify user management on Linux systems, as opposed to manually editing system files such as '/etc/passwd.'

💡Sudo

Sudo is a Linux command that allows a permitted user to execute a command as the superuser or another user with elevated privileges. In the video, the speaker uses 'sudo' to perform administrative tasks like creating users and modifying groups, which require root access.

💡Password File (/etc/passwd)

The '/etc/passwd' file is a key Linux system file that stores information about user accounts, including usernames and user IDs. The speaker warns against manually editing this file and instead encourages using command line tools like 'useradd' to manage users, as mistakes in this file can cause system-wide login issues.

💡Usermod

Usermod is a command line tool used to modify user account properties after the account has been created. In the video, the speaker uses 'usermod' to append 'Susie' to additional groups, explaining how using '-aG' ensures that she keeps her existing group memberships while being added to new ones like 'cool people.'

💡Skeleton Directory (/etc/skel)

The skeleton directory ('/etc/skel') contains template files that are copied into a new user's home directory when the account is created. The speaker demonstrates how to pre-populate 'Susie's' home folder with a file from the skeleton directory, ensuring that newly created users start with specific files or configurations.

💡Password Assignment

Password assignment refers to setting or changing a user's password so they can log in. The speaker uses the 'passwd' command to assign 'Susie' a password after creating her account, emphasizing that newly created users do not automatically have a password, so this step is necessary for them to access the system.

Highlights

Introduction to the video with a humorous apology for the clip.

Overview of being a system administrator, humorously described as boring.

Explanation of how to create, delete, and modify users on a Linux system.

Discussion on manually editing the password file versus using command line tools.

Introduction to the 'useradd' command for adding new users.

Demonstration of using the 'useradd -h' command to display help options.

Description of key flags for the 'useradd' command, including specifying home directories and groups.

Step-by-step guide on creating a user named 'Susie' with specific home directory and permissions.

Explanation of creating and adding a new group called 'cool people' using 'groupadd'.

Highlight of the 'usermod' command to modify existing users and append them to groups.

Discussion on using 'userdel' to remove users and their associated files.

Explanation of the 'skel' directory to prepopulate new user directories with default files.

Demonstration of assigning a password to a new user using the 'passwd' command.

Logging into the newly created user account 'Susie' and verifying setup.

Final advice to use command line tools instead of manually editing system files to avoid errors.

Transcripts

i'm so sorry for the video clip you're

about to watch

being a system administrator is really

quite boring

i know

[Music]

[Applause]

oh

why am i here well i was i was lonely so

i

yeah but it's just me

so we're the same well i know i mean

it's

user delete

uh let's see what can i do and oh i know

user and

so

okay i'd like to say that i'm never

going to do something like that again

but that's probably a lie that was kind

of fun so anyway what i do want to cover

though is creating and deleting and

modifying users on your linux system now

if you've been watching videos along

this series with me uh you'll know that

you can actually do this by hand by

editing the password file like manually

and i'll put a link to the video i think

over here is where the the link will be

so that if you want to watch that how

you can do it manually you can but there

are tools on the command line and that's

a much much easier way to manage local

users and to quote the mandalorian

this is the way you don't want to do it

manually because it's too easy to make a

typo or forget what you're doing or get

permissions wrong on a newly created

home directory just use the tools

especially since they're super easy to

use

so rather than show a slide with the

different tools on it i'm just going to

directly show you how to

add and delete users so the first thing

we're going to do is look at the user

add program so i'm going to do user

add-h and i'm going to pipe that through

the head command and if you're not

familiar with the head command we

learned this in another video in this

series and i don't know i guess maybe

you should watch this series it's kind

of a fun series it's quick it's easy and

there's some cool little nuggets like

how to use the head command anyway we do

this and we're going to see the top of

the command like flags the help screen

and there's a couple that i want to

point out now you can modify lots of

things about a user but by default it's

going to do a lot of this stuff anyway

the ones that i want to focus on are we

can specify the home directory like

where the user's home uh files and where

all their directory or where their files

in the directory are stored so we're

going to specify that

you can also specify supplementary

groups that go along with the main group

that will be created when we create them

so supplementary groups are the groups

that are not the same as their name so

like we're going to create the user

susie that will be her main group but we

can add her to other groups as well

we're going to talk about the scale

directory we're going to use a default

one but i want to talk about that at the

end of this video and then lastly i want

to make sure that we do the dash m

create the home because that's going to

create susie's home folder and it's

going to make sure it has the right

ownership and permission so susie will

be able to actually log in so we have

all the stuff right there let's actually

do it we're going to say sudo we have to

be root in order to create a user so

we're going to do sudo user ad

dash d and her home folder is going to

be home

susie and i would probably put it there

by default but i really want us to

specify where her home folder is going

to be so it's going to be right there

and then dash lowercase m so it goes

through the process of creating that

home folder so this would just specify

where it was but if we want to actually

have it created we need to do the dash m

and then dash capital g

and i want susie to be an administrator

so i want to add her to the

supplementary group sudo and adm so i

want her to have those groups if i press

enter

oh i forgot to specify her name so at

the last command or the last part of it

is susie right we have to say uh user ad

to the directory home susie create the

directory put the user in the these two

groups and then you have to actually

tell the command what is her name gonna

be i just forgot to type that so anyway

suzy and now we've created the user

susie we can see that by typing id

suzy and sure enough there she is uh

she's uid 1002 suzy group id 1002 susie

and then the supplementary groups that

we added her to of course there's the

her main group but then the adm and the

pseudo group that we added right up here

so that is how susie is now um

she has an account on our computer if we

look at the home directory we're going

to see

our two users bob and s powers already

were there and now susie has her home

directory there as well now i want to

show you can also add a group really

easily too there's not as many commands

there so we're just gonna actually say

sudo

group add

cool people

okay so now cool people is there but if

we still look at the idea of susie she

doesn't belong to that group because we

just created it didn't even exist when

we created her user so in order to add

her to that group we're going to use

another command and this one isn't

actually spelled out for you to learn in

the linux essentials objectives but it's

vital for you to know so we're just

going to cover it i'm going to say sudo

user mod

dash h if i want to see the help and the

same thing i'm going to pipe this

through

the head command and i want to show 25

lines

and what i specifically want to point

out here are these two things so dash

capital g just like when we're creating

a user we can add them to a

supplementary group so that's how we're

going to add susie to the cool people

group however we also have to specify

dash a and append it because

that will append this group to her list

of groups otherwise if we just do

capital g and put cool people that will

be the only supplementary group she

belongs to she will no longer be in the

adm and the pseudo group so we have to

append

to her list of groups that's vitally

important that we do both of these and

that's really why i wanted to show you

the help list so anyway we're gonna do

sudo

user mod

dash g

cool people and dash a so it appends and

then of course the username who we want

to add to that group is susie and now if

we do an id of susie

oh look at that susie still is in the

same groups that she was before

but also now she's in the cool people

group that we created and added her to

after the fact now there are some cool

things remember i mentioned the skeleton

group well if we look so i'm going to do

sudo

ls

home

susie

there's nothing in there because susie

was created with an empty home directory

but what if we wanted to preload

somebody's folder with some files well

we can do that but we have to do it

before we actually create her so let's

get rid of susie we're going to say sudo

user

dell and i want to do dash h so we can

see the options here and what we're

going to do is we're going to force it

so that it removes her files

and we want to make sure it removes her

home directory and her mail spool she

doesn't actually have a mail spool setup

but it's going to remove everything

about susie if we do r and app so we're

just going to say sudo user dell dash rf

susie and of course yeah it says there

is no mail spool there but if we look in

like the home directory now susie's gone

if we grep susie uh from the etc

password file

there's none in there and if we do id of

susie it's gonna be like there's no such

user okay so what i wanna do is go into

a folder called etc

scale all right and if we do ls there's

no main files in here but what if we

were to do sudo

um touch

cool file for

cool people

and now inside the scale folder there's

a file called cool file for cool people

okay and it's just an empty file we just

touched it and created an empty file but

it's there and now if we type cd if we

create a user again the next user we

create should have this automatically

put into their home folder so let's

create susie again from scratch and see

if that happens so we're going to say

sudo

user ad dash d home susie

dash m for create it dash g

we're going to put her in the sudo group

the adm group and the cool people

group

and then her name of course is going to

be susie press enter and now id susie

make sure we got it all in place yup

she's there it's all working and now if

we do sudo ls i have to do sudo because

otherwise the s powers user wouldn't

have access to susie's home folder but

if we do home

suzy and look inside her folder look at

that cool file for cool people was

automatically put in her folder

a copy of that etc skeleton folder or

etc scale is put in new users so you can

pre-populate things for when you create

new user accounts now one last thing we

have to do is when we create a user it

doesn't have a password so we have to

assign suzy a password if we want her to

actually be able to log in and that's a

really simple command it's the same

command that you change your own

password with right if i was going to

change my own password i would say pass

swd and it would ask me for my old

password and change it twice but if you

have root privilege like with sudo you

can say p-a-s-s-w-d

with the user as an argument so sudo

password of susie it's gonna say what is

her new password i'll say

suzy

suzy which is a terrible password don't

actually use a person's username as our

password but i want to show you that if

we now ssh which is a way to connect to

a computer uh localhost

it's go oh i did the wrong thing okay

ssh suzy at localhost so i'm trying to

connect to our local machine as susie

and i type in the suzy password and now

who am i who am i

i'm susie and i'm logged in in the susie

home folder and there's the cool file

for cool people now oddly creating and

deleting users is not something you do

all that often but if you do have to do

it please be sure to use the command

line tools rather than trying to

manipulate the password and the group

and the shadow file and everything by

hand because it's just an easy way to

make a mistake and create a an error

that'll lock possibly everybody out of

the system if you screw up the password

file even you won't be able to log in

right so use those tools that's what

they're there for um and remember to

learn everything

do what you love and most importantly be

kind if you have comments please leave

them in the comment section below and i

will see you in the next video bye