View source for Linux-for-Sys-Ads/C2/Creating-user-account/English

'''Title of script: Creating User Account'''

'''Author: Antara Roy Choudhury'''

'''Keywords: Creating user account, Different options, Specify user ID, Specify home directory, Specify login shell, Specify comments, /etc/passwd, /etc/shadow'''



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|| '''Visual Cue'''
|| '''Narration'''
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|| Slide 1: Introduction
|| Hello and welcome to the spoken tutorial on '''Creating User Account''' in '''Linux.'''
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|| Slide 2: Learning Objectives
|| In this tutorial we will learn about

*Creating '''user account '''with different options
*'''/etc/passwd file'''
*'''/etc/shadow file'''
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|| Slide 3: System requirement
|| To record this tutorial, I am using '''Ubuntu Linux 16.04 OS'''
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|| Slide:4 Prerequisite
|| To practice this tutorial, 
*You should have gone through the''' Linux '''tutorial series''' '''on this website.
*And you must have '''root access '''to the computer.
|-
|| Slide 5:
|| In an earlier tutorial on basics of '''system administration''', we have learnt

*To add a''' user '''using the following command:

'''adduser space option space username'''*Please note that the '''option field '''here, is not mandatory.
*We will elaborate on the '''option field''' in this tutorial.

|-
|| Press Ctrl+Alt+T
|| Open the '''Terminal '''by pressing '''Ctrl, Alt and T '''keys simultaneously on the keyboard.
|-
|| Type 

sudo su

[Enter]
|| First, you should login as '''superuser '''or '''root user'''.

To do so type: '''sudo space su '''and press '''Enter.'''
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|| Type

Password of your account

[Enter]
|| Type your''' password '''and then press '''Enter'''.
|-
|| Highlight # prompt
|| Notice, our '''login prompt '''has changed to a '''hash''' symbol.

This indicates that we are in the '''root user '''mode.
|-
|| Slide with a block diagram to explain the scenario
|| Now, let’s consider a scenario of a college.

We will have students, departments, etc.

As a '''system administrator''', you should first create a '''user account '''for individual students. 
|-
|| adduser amit

[Enter]
|| Let’s add one '''user''' say '''amit''' using '''adduser command'''.

So, on the '''terminal '''type: 

'''adduser space amit '''and press '''Enter'''
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|| Type

pass_amit

[Enter]
|| It will prompt us to type the '''password''' for the''' user amit.'''

Let’s type '''pass underscore amit '''and press '''Enter.'''
|-
|| Retype the same password

[Enter]
|| Retype the same '''password '''and press '''Enter.'''
|-
|| Type 

Amit

[Enter]
|| When it prompts for the '''Full Name '''field, type the name of the '''user '''as '''Amit '''with '''A '''in caps.

Press '''Enter.'''

Leave the other fields empty by pressing the '''Enter key.'''
|-
|| Press Y
|| Press '''Y '''to confirm that the information you provided is correct.

Press '''Enter'''
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|| On getting # prompt back
|| So, we got back our '''root command prompt.'''

The user '''amit''' is now created.
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|| Highlight appropriately in the output of previous command
|| '''Linux''' automatically assigns a '''UID '''or''' User ID''' to the '''user'''.

|-
|| Highlight appropriately in the output of previous command
|| It also creates a '''home directory '''for the '''user '''in the '''system’s home''' folder.

In this case, it is '''/home/amit'''
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|| Highlight appropriately in the output of previous command
|| A '''group '''is also created with the same name as the '''username '''of the '''user'''.
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|| Slide 6a:

|| Now, say 
*we want a '''customized user ID '''or '''group '''
*Or a '''home directory''' other than the default one
*Or we want to change the '''default login shell '''

|-
|-
|| Slide 6b:
|| 
*'''adduser''' supports options for each of these requirements.
*Also you can combine multiple options to set multiple values in a single '''command'''.

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|| Slide 7:
|| 
*'''Hyphen u '''option is used to set '''user ID'''
*'''Hyphen home''' sets '''user home directory'''
*'''Hyphen shell '''sets the '''login shell '''for the '''user'''
*'''Hyphen c''' option is used to mention '''comments'''

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|| Slide 8:
|| Let us take an example.

Say we want to add a '''user Kaushik with '''
*'''user ID '''as '''1050'''
*'''home directory '''as '''testdir '''
*'''login shell '''as''' /bin/sh'''
*Also add “'''Kaushik is a re-registered student” '''in the''' comments'''.

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|| Type:

adduser -u 1050 -home /home/testdir/ -shell /bin/sh 

-c "Re-Registered student"

kaushik

[Enter]
|| Switch to the '''terminal.'''

Let me clear the '''terminal'''.

Type the '''command '''as shown here 

Press '''Enter.'''
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|| Type

pass_kaushik

[Enter]
|| It will ask you to enter the '''password''' for '''Kaushik.'''

I will type the '''password '''as '''pass underscore kaushik '''

press '''Enter.'''
|-
|| Type

pass_kaushik

[Enter]
|| Retype the same '''password '''and press '''Enter.'''
|-
|| Type Kaushik

[Enter]
|| Give the '''Full Name '''of the '''user '''as '''Kaushik '''with '''K''' in caps 

press '''Enter.'''
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|| Press Enter
|| And proceed as we have done before.
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|| Show the output
|| So, the''' user kaushik''' is created now.
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|| Type:

ls /home/

[Enter]
|| Now type '''ls space /home '''and press '''Enter.'''


Notice, we have a new '''directory testdir.'''
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|| Slide 9:
|| How can we view other information such as '''user ID, login shell '''etc.?
*In '''Linux''', all '''configuration files '''are stored in simple '''text files'''.
*'''''/etc/passwd'' '''file contains the entire information about all the '''user accounts.'''

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|| cat /etc/passwd

[Enter]
|| Let us have a look at the '''/etc/passwd '''file.

Switch to the '''terminal''' 

Type '''cat space /etc/passwd '''and press '''Enter.'''
|-
|| Show file opened

And scroll down until you see user amit and kaushik

Highlight rows
|| There will be an entry in this file for every '''user '''on the system.

Our '''passwd''' file shows this line for user '''Amit'''.

Each line has seven '''fields '''separated by '''colon'''.

Let us understand the '''fields '''one by one.
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|| Slide
|| 
*The first '''field '''is the '''username amit.'''
*Remember, '''username '''should start with a lowercase letter
*Followed by any number of lowercase letters or digits
*No special character other than '''underscore '''is allowed in the '''username'''

You should remember this while you are creating a '''user account'''
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|| Slide
|| The second field is for '''password'''.

An '''x''' character indicates that the '''encrypted hash password '''is stored in the file '''/etc/shadow'''.
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|| Slide
|| The third field is '''user ID '''for that particular '''user'''.
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|| Slide
|| 
*'''User id 0''' is reserved for '''root user'''.
*'''User ids '''upto '''999 '''are reserved for other '''administrative '''or '''system users'''.
*Real '''user account id''' starts from '''1000'''.
*So, you should specify a number more than '''1000 '''in the '''adduser command'''.

|-
|| Slide
|| The fourth '''field '''stores the '''primary group id''' for the '''user'''.

At the fifth place, we have the''' comments field'''.

It basically stores information about the '''user '''such as name of the '''user''', '''room number, phone number, '''etc.
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|| Slide
|| The sixth '''field '''indicates the '''home directory''' for the '''user'''.

At the end, we have the '''login shell '''of the '''user'''.
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|| Switch to terminal and highlight the rows for amit and kaushik
|| Notice that, we have default values set for '''user Amit.'''

However, '''user kaushik '''is created with our customized values.
|-
|| Type

cat /etc/shadow
|| Now, let’s have a look at the '''/etc/shadow''' file, where the '''encrypted passwords '''are stored.

Type '''cat space /etc/shadow '''and press '''Enter.'''
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|| Show the output and highlight 
|| In this file, every line has information about a particular '''user'''.

And each line contains various fields separated by '''colon'''.

The first '''field '''is '''username''', which must correspond to '''username field '''in '''/etc/passwd''' file.
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|| (Suppose the entry looks like this 

Amit:yh65fgtr) 

Then highlight yh65fgtr
|| Notice, the second '''field '''is the '''encrypted password '''for that '''user'''.

Let us skip the other '''fields '''for now.
|-
|| Type '''exit '''and press '''Enter'''
|| To exit from the '''root user access''', type '''exit''' and press '''Enter.'''
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|| Retain same screen
|| This brings us to the end of this tutorial.

Let us summarize.
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|| Display Slide 16:

Summary
|| In this tutorial we learnt about-
*Creating '''user account '''with different options like
** Specific '''user id'''
** Specific '''Home Directory'''
** Specific '''shell'''
*And adding '''comments '''

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|| Display Slide 16:

Summary
|| We also learnt about some of the '''fields '''in the *'''/etc/passwd '''and
*'''/etc/shadow '''files.

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|| Slide 17:

Assignment

|| As an assignment 

Create '''user ankit '''with 
*'''User ID '''as '''1500'''
*'''Home directory '''named '''ankit underscore newdir'''
*'''Login shell '''as '''/bin/csh'''

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|| Slide 18:
|| 
*Include''' “Hostel 15”''' in the '''comment'''
*Use a single '''command''' to perform all the tasks
*Check the''' /etc/passwd''' file for the details of '''user account ankit'''

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|| Slide 19: About Spoken Tutorial project
|| The video at the following link summarises the Spoken Tutorial project.

Please download and watch it.
|- 
|| Slide 20: Spoken Tutorial workshops
|| The '''Spoken Tutorial Project''' team conducts workshops and gives certificates.

For more details, please write to us.
|-
|| Slide: Forum for specific questions:
|| Do you have questions in this Spoken Tutorial?

Please visit this site.

Choose the minute and second where you have the question.

Explain your question briefly.

Someone from our team will answer them.
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|| Slide: Forum for specific questions:
|| The Spoken Tutorial forum is for specific questions on this tutorial.

Please do not post unrelated and general questions on them.

This will help reduce the clutter.

With less clutter, we can use these discussion as instructional material.
|- 
|| Slide 22: Acknowledgement
|| Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.
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|| Slide 23: Thank You
|| The script has been contributed by Antara and this is Praveen from IIT Bombay signing off.

Thank you for joining.
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