Madhurig: Madhurig moved page Linux-Ubuntu/C2/Linux-File-Ownership-and-Permissions/English to Linux-New/C2/Linux-File-Ownership-and-Permissions/English

2026-03-24T11:10:18Z

Madhurig moved page Linux-Ubuntu/C2/Linux-File-Ownership-and-Permissions/English to Linux-New/C2/Linux-File-Ownership-and-Permissions/English

Madhurig at 11:53, 11 March 2026

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Madhurig at 12:10, 27 January 2026

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Ketkinaina at 11:31, 27 January 2026

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Ketkinaina at 11:29, 27 January 2026

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Ketkinaina: Created page with "'''Title of the Script:''' '''Linux File Ownership and Permissions''' '''Authors:''' '''Edupyramids''' '''Keywords:''' Linux, File Ownership, File Permissions, chown, chmod,..."

2026-01-25T20:08:08Z

Created page with "'''Title of the Script:''' '''Linux File Ownership and Permissions''' '''Authors:''' '''Edupyramids''' '''Keywords:''' Linux, File Ownership, File Permissions, chown, chmod,..."

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'''Title of the Script:''' '''Linux File Ownership and Permissions'''

'''Authors:''' '''Edupyramids'''

'''Keywords:''' Linux, File Ownership, File Permissions, chown, chmod, chgrp, Inodes, Hard link, Soft link, Symbolic link, Terminal commands, Linux file system, edupyramids, video tutorial.

{|border=1
|-
|| '''Visual Cue'''
|| '''Narration'''
|-
|| '''Slide 1'''

'''Title Slide'''
|| Welcome to this spoken tutorial on '''Linux File Ownership and Permissions.'''
|-
|| '''Slide 2'''

'''Learning Objectives'''
|| In this tutorial, we will learn to:
* Manage file ownership and permissions using '''c h own''' and '''c h mod''' commands.
* Change file group ownership using '''chgrp''' command.
* Describe '''i nodes '''and view '''i node''' numbers of the files.
* Create and verify '''hard links '''and '''symbolic links''' in Linux.
|-
|| '''Slide 3'''

'''System Requirements'''
|| To record this tutorial, I am using:

'''Ubuntu O S version 24 point 04'''
|-
|| '''Slide 4'''

'''Pre-requisites'''

[https://EduPyramids.org/ https://EduPyramids.org]<span style="color:#1155cc;"> </u>
|| To follow this tutorial,

learners should have '''Ubuntu version 24 point 04.'''

For the prerequisite Linux tutorials please visit this website.
|-
|| '''Slide 5'''

'''Code Files'''

The following code file is required to practice this tutorial.
# '''file-attr.zip'''
# '''fa-commands.txt'''

This file is provided in the '''Code Files''' link of this tutorial page.
|| The following code files are required to practice this tutorial.

These files are provided in the '''Code Files''' link of this tutorial page.
|-
|| '''Slide 6'''

'''File Attributes'''

'''File-attributes.png'''
|| File attributes are properties linked to a file.Attributes define ownership and permissions.

They include file type, size, and time details.They show who owns the file and who can access it.

File attributes are viewed using the '''l s hyphen l '''command.
|-
|| Switch to terminal

Type''' cd Desktop/file-attr'''

Press '''Enter'''

Highlight the output

'''/Desktop/file-attr$d'''
|| Let us move to the code files folder '''file hyphen attr'''

provided along with the tutorial.

I have downloaded it to my '''Desktop'''.

Now switch to the terminal.

Type '''c d space Desktop slash file hyphen a t t r '''and press Enter.Notice that the prompt path has changed.
|-
|| Type

'''ls -l example1'''

and press''' Enter'''

'''Highlight the output'''

'''point to the first character'''
|| Let us type

'''l s space hyphen l space example1'''

and press '''Enter. '''

Observe the output.

The first character in the output shows the file type.

If it is a '''hyphen''', it denotes a regular file.

If it is '''l,''' it denotes a '''symbolic link'''.

If it is '''d''', it denotes a '''directory.'''

We see a hyphen here since example1 is a regular file.
|-
|| highlight the next 9 characters
|| The next nine characters show '''permissions'''.

First three denote '''owner''' permissions,

Next three denote '''group''' permissions,

Last three denote '''others''' permissions

Here each set contains '''r, '''and''' w,''' means '''read, '''and''' write'''.
|-
|| Highlight '''example1'''

highlight '''spoken'''
|| Here we can see that the owner of the file '''example1''' is '''spoken'''.
|-
|| '''Slide 7'''

'''chown command'''
* The''' chown''' command changes the ownership of a file or directory.
* This is an admin command.
* Only the root user can change the owner of a file or directory.

'''chown [options] ownername filename or directoryname'''
|| * The''' c h own''' command changes the ownership of a file or directory.
* This is an admin command.
* Only the root user can change the ownership of a file or directory.
* Here is the syntax of the '''c h own''' command.
|-
|| '''Slide 8'''

'''chown options'''
* -R: change permissions for all files in the current directory and its sub-directories.
* -c: report changes made to files.
* -f: prevent chown from displaying error messages.
|| The '''c h own''' command comes with various options like '''hyphen R, hyphen c, hyphen f''' and others.
|-
||
|| Now we will look at some examples.
|-
|| '''Type'''

'''sudo chown demo example1'''

press '''Enter'''.
|| Let us change the owner of the '''file''' '''example1'''.

Type '''sudo space ch own space demo space example1'''

press Enter.
|-
|| Type the sudo password if prompted.
|| Type the password if prompted again.
|-
|| Type

''' ls -l example1'''

press Enter

Highlight the output
|| Let us see the file attributes of '''example'''1.

Type '''l s space hyphen l space example1''' and press Enter.

Observe that the new owner of the '''file''' is '''demo'''.

This works only if the user named '''demo''' exists.

Otherwise we will get an '''invalid user''' error.

Recall that we have given you an assignment in an earlier tutorial to create a user named''' demo'''.

If the user does not exist, please create the user.
|-
|| Type

'''mkdir pond'''

and press Enter.

Type the command

'''ls -l'''

press Enter

Highlight the pond directory details

highlight examples 1 to 5.
|| Now, we will see how to change the owner''' '''of a '''directory.'''

For that we will create a directory first.

Type '''m k dir space pond '''and press Enter.

To check, type '''l s space hyphen l '''and press Enter.

It displays a directory named''' pond''' and all the existing files examples.

Here we can see the owner of the directory '''pond''' is '''spoken'''
|-
|| Type

'''sudo chown -R demo pond '''
|| Let us change the owner of the directory''' pond''' to '''demo.'''

Type the following command and press '''Enter '''

Enter the sudo password, if required and press Enter again.
|-
|| Press '''Ctrl+L''' keys together.

Type '''ls -l '''and press '''Enter'''.
|| I will clear the screen by pressing '''Ctrl + L''' keys together for our convenience.

Now type,'''l s space hyphen l '''and press '''Enter'''

Here we can see the new owner of the directory '''pond''' is '''demo'''.
|-
|| '''Slide 9'''

'''Changing File Permissions'''

ch mod command is used to change the permissions of a file or directory.

The name chmod stands for change mode.

Using chmod we can grant or remove permissions for owner, group and others.

read (r)

write (w)

execute (x)

The command modifies only the permissions, not the file contents or ownership.
|| '''ch mod''' command is used to change the permissions of a''' file '''or''' directory'''.

The name''' c h mod '''stands for change mode.

Using '''chmod '''we can add or remove permissions such as: '''read, write, execute'''.

These permissions can be changed''' '''for '''owner, group '''and '''others.'''

It does not modify the file contents or change ownership.
|-
|| '''Slide 10'''

'''Syntax of chmod command'''

chmod [ugoa][+-=][rwx] file-or-directory
|| This is the syntax of the '''c h mod''' command.
|-
|| '''Slide 11'''

'''Permissions using three-digit octal number'''

chmod [0-7][0-7][0-7] file_or_directory

Each digit represents:

1st digit → owner permissions

2nd digit → group permissions

3rd digit → others permissions

Permission values:

r = 4 (read)

w = 2 (write)

x = 1 (execute)
|| Alternatively, we can set permissions using a three digit octal number.
|-
|| Press Clear and press Enter.
|| Now, we will look at some examples of '''ch mod'''.

Let me clear the screen
|-
|| Type'''chmod u+x example2'''

press Enter
|| To add execute permission to the '''owner''' of the file '''example2''' type:'''ch mod space u plus x space example2 '''and''' '''press '''Enter.'''

This will add the execute permission to the owner of the file example2.
|-
|| type

''' ls -l example2

'''press '''Enter'''

highlight the permissions in the output
|| To check that, type

'''l s space hyphen l space example2'''

and press '''Enter''' to see the changes

It has assigned''' read, write''', and''' execute '''permissions to the '''owner.Read '''and''' write''' only permissions to the '''group'''.And '''read-only''' permission to '''others''', for the file example2.
|-
|| Type

'''chmod 751 example2

'''press Enter

type '''ls -l example2'''

and press Enter

Highlight the output
|| Now type the command

'''ch mod space 751 space example2

'''press '''Enter'''

This command gives the''' owner read, write''', and '''execute '''permissions.

To check type, '''ls space hyphen l space example2''' and press Enter.

'''Read''' and '''execute''' permissions to the '''group'''.

And '''execute-only '''permission to '''others '''for the file '''example2'''.
|-
|| type '''chmod a<nowiki>=</nowiki>r example2'''

and press '''Enter'''
|| To assign '''read-only''' permission to '''example2''' for everyone, type the following command:

'''ch mod space a equal to r space example2''' and press '''Enter.'''
|-
|| type '''ls -l example2'''

press Enter

Highlight the output
|| Now type the command,

'''l s space hyphen l space example2 '''

and press Enter.

Observe that the file '''example2''' has '''read-only '''permission for all users.
|-
|| Type '''chmod g+w example3 '''

and press Enter
|| Let’s add the write permissions to the group for file '''example3'''.

Type the command'''ch mod space g plus w space example3 '''

and press '''Enter'''.
|-
|| Type'''ls -l example3'''

press Enter

Highlight the output
|| Now type,'''l s space hyphen l space example3'''

press '''Enter'''.

Note that the write permission has been added to the group.
|-
|| Type '''chmod a-w example3'''

press '''Enter'''
|| To remove the write permissions for all,type the command'''ch mod space a hyphen w space example3'''

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

'''ls -l example3'''

press Enter

Highlight the output
|| Now type, '''l s space hyphen l space example3'''

press Enter.

Observe that write permission for all has been removed
|-
|| '''Slide 12 '''

'''chgrp command'''

'''Ch-grp.png'''
||
* '''ch grp''' command changes the '''group ownership''' of a file or directory.
* Group members can then access it based on the set permissions'''.'''
* Only the owner of a file or a privileged user can change the group.
|-
|| '''Slide 13'''

'''Syntax of chgrp command'''
* The basic syntax of the ch grp command is:'''chgrp [options] group file'''
* To change the group of a directory and all its contents recursively:'''chgrp -R group directory'''
* Here, '''group''' is the new group name, and '''file''' or '''directory''' is the target.
||
* The basic syntax of the''' ch g r p''' command is:'''ch grp options group file.'''
* To change the group of a directory and all its contents recursively type:'''ch grp hyphen R group directory.'''
* Here, '''group''' is the new group name, and '''file''' or '''directory''' is the target.
|-
|| Switch to terminal

Press Clear and press Enter.

type

'''ls -l example4'''

press '''Enter'''

Highlight the permissions in the output
|| Let's look at some examples of '''ch grp''' commands.

Type the command,

'''l s space hyphen l space example4 '''

and press '''Enter.'''

Here we can see the group permission is given for the user '''spoken'''.
|-
|| Type '''sudo chgrp demo example4'''

press Enter
|| To change the group permission, type the command'''sudo space ch grp space demo space example4 '''press Enter.Enter the sudo password, if required.
|-
|| Type

'''ls -l example4'''

press '''Enter'''

Highlight the permissions in the output
|| Now type the command'''l s space hyphen l space example4'''

press '''Enter'''

Observe that the group has changed from '''spoken''' to '''demo'''
|-
|| '''Slide 14'''

'''Inode'''
|| An '''i node''' is a unique number that stores file or directory information.

Files are hard links to i nodes, which the system uses to access data.
|-
|| Switch to the terminal

type the command

'''ls -i example5'''

press Enter

Highlight the number in the output
|| We can use''' l s space hyphen i''' command to see the '''i node '''number of a file.

type the command,''' l s space hyphen i space example5'''

press '''Enter.'''

The number written before the file is the i node number of the file.

The '''i node''' number may vary for the users.
|-
|| '''Slide 15'''

'''Hard Links'''
|| A hard link is another name for an existing file.

Both files point to the same '''i node.'''

Since they share the same i node, they share the same data on disk.

The file is not copied, only a new filename is created.
|-
|| '''Slide 16'''

'''Inode and Hard Links'''
|| An i node can have multiple directory entries through hard links.

Hard links let multiple filenames point to the same i node.

To create links in Linux, we use the '''ln''' command.
|-
|| '''Slide 17'''

'''Syntax of ln'''

'''ln source link'''
|| The syntax of '''ln''' command to create a hard link is:

'''ln space source space link'''

The source is an existing file, and the link is the new filename.

Both files point to the same i node and share the same data.

Any change made to one file will reflect in the other file.
|-
|| Type: clear

and press enter

'''ln example2 exampleln'''

press Enter

Point to the command.
|| Now we will look at some examples of hard links

Let me clear the screen again.

Type the command,

'''l n space example2 space example l n'''

press Enter.

This command creates a hard link named '''exampleln''' to the file '''example2.'''
|-
|| Type '''ls -i example2 exampleln'''

press Enter

Highlight to the output
||

To display the i node number of both the files, type the command'''l s space hyphen i space example2 space exampleln'''

and press '''Enter.'''

The output shows that both files have the same i node number.

File '''exampleln''' is the hard link for file example2
|-
|| '''Slide 18'''

'''Soft Link'''
|| A soft link or a symbolic link is a special type of file.

It holds a reference to another file or directory.

This reference is an absolute or relative path.
|-
|| '''ln -s target-filename symbolic-filename'''
|| The syntax of''' l n command''' to create soft links is'''l n space hyphen s space target hyphen filename space symbolic hyphen filename.'''
|-
||
|| Now we will look at some examples of soft links.
|-
||

type '''ln -s example2 examplesoft''' press Enter
|| To create a soft link, type the command

'''l n space hyphen s space example2 space examplesoft '''and press Enter.
|-
|| type the command

''' ls -li example2 examplesoft '''press Enter
|| Now, let us display the i node number and list both the files.

Type the command,

'''l s space hyphen l i space example2 space examplesoft'''

press '''Enter.'''

Observe that the '''i node''' number of both the files is different.

'''examplesoft''' is a''' soft link''' of''' example2'''.
|-
|| '''Slide 19'''

'''Summary'''

In this tutorial, we have learnt to:
* Manage file ownership and permissions using '''chown''' and '''chmod''' commands.
* Change file group ownership using '''chgrp''' command.
* Describe '''inodes '''and view '''inode''' numbers of the files.
* Create and verify '''hard links '''and '''symbolic links''' in Linux.
|| With this we come to the end of this tutorial.

Let us summarise.
|-
|| '''Slide 20'''

'''Assignment'''
# Create a file named '''sample.txt'''.
# Display its permissions using the ls -l command.
# Change the permissions so that only the owner can read and write the file.
# Display the inode number of '''sample.txt'''.
|| As an Assignment, please do the following.
|-
|| '''Slide 21'''

'''Thank you'''
|| This '''Spoken Tutorial''' is brought to you by '''EduPyramids Educational Services Private Limited SINE IIT Bombay.'''Thank you.
|-
|}

@@ Line 124: / Line 124: @@
 Last three denote '''others''' permissions
-Here  '''r,  w, x''' means '''read, 'write'''   '''execute'''.
+Here  '''r,  w, x''' means '''read''', '''write''' and  '''execute'''.
 |-
 || Highlight '''example1'''

← Older revision	Revision as of 11:10, 24 March 2026
(No difference)

@@ Line 572: / Line 572: @@
 |-
 || '''ln -s target-filename symbolic-filename'''
-|| The syntax of''' l n command''' to create soft links is'''l n space hyphen s space target hyphen filename space symbolic hyphen filename.'''
+|| The syntax of''' l n command''' to create soft links is'''l n space hyphen s space target filename space symbolic filename.'''
 |-
 ||

@@ Line 60: / Line 60: @@
 '''File-attributes.png'''
-|| File attributes are properties linked to a file.Attributes define ownership and permissions.
+|| File attributes are properties linked to a file. Attributes define ownership and permissions.
-They include file type, size, and time details.They show who owns the file and who can access it.
+They include file type, size, and time details. They show who owns the file and who can access it.
 File attributes are viewed using the '''l s hyphen l '''command.
@@ Line 83: / Line 83: @@
 Now switch to the terminal.
-Type '''c d space Desktop slash file hyphen a t t r '''and press Enter.Notice that the prompt path has changed.
+Type '''c d space Desktop slash file hyphen a t t r '''and press Enter. Notice that the prompt path has changed.
 |-
 || Type
@@ Line 314: / Line 314: @@
 and press '''Enter''' to see the changes
-It has assigned''' read, write''', and''' execute '''permissions to the '''owner.Read '''and''' write''' only permissions to the '''group'''.And '''read-only''' permission to '''others''', for the file example2.
+It has assigned''' read, write''', and''' execute '''permissions to the '''owner.
 |-
 || Type
@@ Line 446: / Line 450: @@
 press Enter
-|| To change the group permission, type the command'''sudo space ch grp space demo space example4 '''press Enter.Enter the sudo password, if required.
+|| To change the group permission, type the command'''sudo space ch grp space demo space example4 '''press Enter. Enter the sudo password, if required.
 |-
 || Type