Difference between revisions of "Linux/C2/File-Attributes/English-timed"

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|'''Time'''
 
|'''Time'''
 
|'''Narration'''
 
|'''Narration'''
 +
 
|-
 
|-
 
| 00:00
 
| 00:00
 
| Welcome to this spoken tutorial on '''Linux''' '''File Attributes'''.
 
| Welcome to this spoken tutorial on '''Linux''' '''File Attributes'''.
 +
 
|-
 
|-
 
| 00:05
 
| 00:05
 
| The prerequisites for this tutorial is to create empty files named as example1, example2, example3, example4, example5, and testchown.  
 
| The prerequisites for this tutorial is to create empty files named as example1, example2, example3, example4, example5, and testchown.  
 +
 
|-
 
|-
 
|00:18
 
|00:18
 
|Please create empty directories named as test_chown and directory1 also.  
 
|Please create empty directories named as test_chown and directory1 also.  
 +
 
|-
 
|-
 
| 00:25
 
| 00:25
 
| A file attribute is ''metadata'' that describes or is associated with a computer file.  
 
| A file attribute is ''metadata'' that describes or is associated with a computer file.  
 +
 
|-
 
|-
 
|00:33
 
|00:33
 
|File attribute is the characteristics that describes a file such as owner, file type, access permissions etc.  
 
|File attribute is the characteristics that describes a file such as owner, file type, access permissions etc.  
 +
 
|-
 
|-
 
| 00:45
 
| 00:45
 
| 'c-h own' command is used to change the ownership of the file or directory. This is an admin command, '''root''' user only can change the owner of a file or directory.  
 
| 'c-h own' command is used to change the ownership of the file or directory. This is an admin command, '''root''' user only can change the owner of a file or directory.  
 +
 
|-
 
|-
 
| 01:00
 
| 01:00
 
| The syntax of '''chown''' command is '''<nowiki>chown space options space ownername space filename or directoryname </nowiki>'''
 
| The syntax of '''chown''' command is '''<nowiki>chown space options space ownername space filename or directoryname </nowiki>'''
 +
 
|-
 
|-
 
| 01:13
 
| 01:13
 
| We may give following options with '''chown''' command.  
 
| We may give following options with '''chown''' command.  
 +
 
|-
 
|-
 
|01:18
 
|01:18
 
|'''-R''' : To change the permission on files that are in the sub-directories of the directory that you are currently in.  
 
|'''-R''' : To change the permission on files that are in the sub-directories of the directory that you are currently in.  
 +
 
|-
 
|-
 
|01:28
 
|01:28
 
|'''-c ''': Change the permission for each file.  
 
|'''-c ''': Change the permission for each file.  
 +
 
|-
 
|-
 
|01:33
 
|01:33
 
|'''-f''' : Prevents '''chown''' from displaying error messages.  
 
|'''-f''' : Prevents '''chown''' from displaying error messages.  
 +
 
|-
 
|-
 
| 01:37
 
| 01:37
 
| Now we will look at some examples.  
 
| Now we will look at some examples.  
 +
 
|-
 
|-
 
| 01:40
 
| 01:40
 
| So, go to the terminal. We will move to the directory where we have created empty files and folders. For that, '''cd space Desktop slash file attribute''' and press Enter.
 
| So, go to the terminal. We will move to the directory where we have created empty files and folders. For that, '''cd space Desktop slash file attribute''' and press Enter.
 +
 
|-
 
|-
 
| 01:56
 
| 01:56
−
| Now type the command:  
+
| Now type the command: $ ls space -l space testchown that is t-e-s-t-c-h-o-w-n and press Enter.
−
$ ls space -l space testchown that is t-e-s-t-c-h-o-w-n and press Enter.
+
 
 
|-
 
|-
 
| 02:11
 
| 02:11
 
| Here we can see the owner of the file 'testchown' is shahid.
 
| Here we can see the owner of the file 'testchown' is shahid.
 +
 
|-
 
|-
 
| 02:18
 
| 02:18
−
| To change the owner of the file, type the command:  
+
| To change the owner of the file, type the command: $ sudo space c-h own space that is a-n-u-s-h-a anusha space testchown that is t-e-s-t-c-h-o-w-n  
−
$ sudo space c-h own space that is a-n-u-s-h-a anusha space testchown that is t-e-s-t-c-h-o-w-n  
+
Press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
| 02:36
 
| 02:36
 
| Enter the sudo password and press Enter again. Press Enter.  
 
| Enter the sudo password and press Enter again. Press Enter.  
 +
 
|-
 
|-
 
| 02:44
 
| 02:44
−
| Now, type: $ ls space -l space t-e-s-t-c-h-o-w-n  
+
| Now, type: $ ls space -l space t-e-s-t-c-h-o-w-n and press Enter. Here we can see the new owner of the file is anusha.
−
and press Enter.  
+
 
−
Here we can see the new owner of the file is anusha.
+
 
|-
 
|-
 
| 03:03
 
| 03:03
 
| Now we will see how to change owner of the directory.  
 
| Now we will see how to change owner of the directory.  
 +
 
|-
 
|-
−
|03:07
+
| 03:07
−
|Type the command: $ ls -l and  press Enter.  
+
| Type the command: $ ls -l and  press Enter. Here we can see the owner of the directory 'test_chown' is shahid.  
−
Here we can see the owner of the directory 'test_chown' is shahid.  
+
 
 
|-
 
|-
 
| 03:21
 
| 03:21
 
| To change the owner of the directory, type the command:  
 
| To change the owner of the directory, type the command:  
 +
 
|-
 
|-
−
|03:26
+
| 03:26
−
|$ sudo space chown space minus capital R space a-n-u-s-h-a anusha space test_chown which is directory name and press Enter.  
+
| $ sudo space chown space minus capital R space a-n-u-s-h-a anusha space test_chown which is directory name and press Enter.  
−
|-
+
 
−
|03:44
+
−
|Enter the sudo password if required and press Enter again.
+
 
|-
 
|-
 +
| 03:44
 +
| Enter the sudo password if required and press Enter again.
  
 +
|-
 
| 03:49
 
| 03:49
−
| I will clear the screen by pressing '''Ctrl+L''' for our convenience. Now type: $ ls space -l and press Enter.  
+
| I will clear the screen by pressing '''Ctrl+L''' for our convenience. Now type: $ ls space -l and press Enter.Here we can see the new owner of the directory is anusha.  
−
Here we can see the new owner of the directory is anusha.  
+
 
 
|-
 
|-
 
| 04:06
 
| 04:06
 
| '''chmod''' command is used to change the access mode or permissions of one or more files.  
 
| '''chmod''' command is used to change the access mode or permissions of one or more files.  
 +
 
|-
 
|-
 
| 04:13
 
| 04:13
−
| Syntax of the '''chmod''' command is  
+
| Syntax of the '''chmod''' command is chmod space [options] space mode space filename We may give the following options with '''chmod''' command.
−
<nowiki>chmod space [options] space mode space filename space chmod space [options] space filename </nowiki>
+
  
−
We may give the following options with '''chmod''' command.
 
 
|-
 
|-
−
|04:29
+
| 04:29
−
| -c : Print information about files that are changed.  
+
|''' -c''' : Print information about files that are changed.  
 +
 
 
|-
 
|-
 
|04:34
 
|04:34
−
| -f : Do not notify user of files that '''chmod''' cannot change.  
+
|'''-f '''': Do not notify user of files that '''chmod''' cannot change.  
 +
 
 
|-
 
|-
 
| 04:41
 
| 04:41
−
| There are following types of access or permissions:  
+
|There are following types of access or permissions:  
 +
 
 
|-
 
|-
 
|04:44
 
|04:44
−
|r : Read  
+
|r : Read, w : Write, x : Execute, s : Set user (or group) ID
  
−
w : Write
 
−
 
−
x : Execute
 
−
 
−
s : Set user (or group) ID
 
 
|-
 
|-
 
| 04:54
 
| 04:54
 
| Alternatively, we may specify permissions by a three-digit octal number.  
 
| Alternatively, we may specify permissions by a three-digit octal number.  
 +
 
|-
 
|-
 
|05:00
 
|05:00
 
|The first digit stands for owner permission, the second stands for group permission, and the third stands for others permission.
 
|The first digit stands for owner permission, the second stands for group permission, and the third stands for others permission.
 +
 
|-
 
|-
 
| 05:09
 
| 05:09
−
| Permissions are calculated by adding the following octal values:  
+
| Permissions are calculated by adding the following octal values: 4 that is Read 2 that is Write 1 that is Execute
−
4 that is Read  
+
  
−
2 that is Write
 
−
 
−
1 that is Execute
 
 
|-
 
|-
 
| 05:20
 
| 05:20
 
| Now we will look at some examples of '''chmod'''. Move to terminal and enter the command to add execute-by-user permission to file 'example1'.
 
| Now we will look at some examples of '''chmod'''. Move to terminal and enter the command to add execute-by-user permission to file 'example1'.
 +
 
|-
 
|-
 
|05:30
 
|05:30
 
| Before that, I will again clear the screen by pressing '''Ctrl+l'''.
 
| Before that, I will again clear the screen by pressing '''Ctrl+l'''.
 +
 
|-
 
|-
−
| 05:36
+
| 05:36
−
| Now, let's type:  
+
| Now, let's type: $ chmod space u+x space example1 press Enter.  
−
$ chmod space u+x space example1  
+
 
−
press Enter.  
+
 
|-
 
|-
−
| 05:49
+
| 05:49
−
| Now type: $ ls space -l space example1  
+
| Now type: $ ls space -l space example1 press Enter to see the changes.  
−
press Enter to see the changes.  
+
 
 
|-
 
|-
 
|06:01
 
|06:01
 
|Here you can see, to assign the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.  
 
|Here you can see, to assign the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.  
 +
 
|-
 
|-
 
| 06:15
 
| 06:15
−
| Now type the command: $ chmod space 751 space example1  
+
| Now type the command: $ chmod space 751 space example1 press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
| 06:26
 
| 06:26
−
| Now type:  
+
| Now type: $ ls space -l space example1 and press Enter.  
−
$ ls space -l space example1  
+
 
−
and press Enter.  
+
 
|-
 
|-
 
|06:35
 
|06:35
 
|Here we can see that above command has assigned the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.  
 
|Here we can see that above command has assigned the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.  
 +
 
|-
 
|-
 
| 06:52
 
| 06:52
 
| To assign read-only permission to file example1 for everyone, type the command: $ chmod space <nowiki>=r space </nowiki>example1  
 
| To assign read-only permission to file example1 for everyone, type the command: $ chmod space <nowiki>=r space </nowiki>example1  
 
and press Enter.  
 
and press Enter.  
 +
 
|-
 
|-
 
| 07:08
 
| 07:08
−
| Now type the command: $ ls space -l space example1  
+
| Now type the command: $ ls space -l space example1 press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
|07:19
 
|07:19
 
|Here we can see that the 'read only' permission has been assigned to file example1 for everyone.  
 
|Here we can see that the 'read only' permission has been assigned to file example1 for everyone.  
 +
 
|-
 
|-
 
| 07:30
 
| 07:30
 
| To change the permission recursively and assign the read and execute access for everyone and also write access for the owner of the directory 'directory1', type the command:  
 
| To change the permission recursively and assign the read and execute access for everyone and also write access for the owner of the directory 'directory1', type the command:  
 +
 
|-
 
|-
−
|7:44
+
|07:44
−
|$ chmod space minus capital R space 755 space directory1  
+
|$ chmod space minus capital R space 755 space directory1. Press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
| 08:00
 
| 08:00
−
| Now type:  
+
| Now type: $ ls space -l press Enter to see the changes.  
−
$ ls space -l  
+
−
press Enter to see the changes.  
+
  
 
|-
 
|-
 
| 08:09
 
| 08:09
−
| To give the user execute permission on file example2, type the command:  
+
| To give the user execute permission on file example2, type the command: $ chmod space u+x space example2 press Enter.  
−
$ chmod space u+x space example2  
+
 
−
press Enter.  
+
 
|-
 
|-
 
| 08:27
 
| 08:27
−
| Now type the command:  
+
| Now type the command: $ ls space -l space example2 and press Enter.  
−
$ ls space -l space example2  
+
 
−
and press Enter.  
+
 
|-
 
|-
 
|08:40
 
|08:40
 
|Here we can see that execute permission has been assigned to user on 'example2'.
 
|Here we can see that execute permission has been assigned to user on 'example2'.
 +
 
|-
 
|-
 
| 08:50
 
| 08:50
 
| To add the write permissions to the group for file example3  
 
| To add the write permissions to the group for file example3  
−
type the command:  
+
 
−
$ chmod space g+w space example3  
+
type the command: $ chmod space g+w space example3. Press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
| 09:10
 
| 09:10
−
| and now type:  
+
| and now type: $ ls space -l space example3 press Enter.  
−
$ ls space -l space example3  
+
 
−
press Enter.  
+
 
|-
 
|-
 
|09:23
 
|09:23
 
|Here we can see the write permission has been added to group.  
 
|Here we can see the write permission has been added to group.  
 +
 
|-
 
|-
 
| 09:30
 
| 09:30
−
| To remove the write permissions for all, type the command:  
+
| To remove the write permissions for all, type the command: $ chmod space a-w space example3  
−
$ chmod space a-w space example3  
+
 
−
press Enter.  
+
Press Enter.  
 +
 
 
|-
 
|-
 
| 09:45
 
| 09:45
−
| Now, type:  
+
| Now, type: $ ls space -l space example3 press Enter.  
−
$ ls space -l space example3  
+
 
−
press Enter.  
+
 
|-
 
|-
 
|09:55
 
|09:55
 
|Here we can see the write permission, for all, has been removed.  
 
|Here we can see the write permission, for all, has been removed.  
 +
 
|-
 
|-
 
| 10:02
 
| 10:02
 
| '''chgrp''' command is used to change the group of one or more files to new group.  
 
| '''chgrp''' command is used to change the group of one or more files to new group.  
 +
 
|-
 
|-
 
|10:10
 
|10:10
 
|New group is either a group ID number or a group name located in /etc/group.  
 
|New group is either a group ID number or a group name located in /etc/group.  
 +
 
|-
 
|-
 
|10:20
 
|10:20
 
|Only the owner of a file or a privileged user may change the group.  
 
|Only the owner of a file or a privileged user may change the group.  
 +
 
|-
 
|-
 
| 10:26
 
| 10:26
−
| The syntax for the '''chgrp''' command is
+
| The syntax for the '''chgrp''' command is chgrp space [options] space newgroup space files.
−
<nowiki>chgrp space [options] space newgroup space files.</nowiki>
+
 
 
|-
 
|-
 
| 10:36
 
| 10:36
 
| Let's go to terminal. Now we will look at some examples of '''chgrp''' command.
 
| Let's go to terminal. Now we will look at some examples of '''chgrp''' command.
−
Type the command: $ ls space -l space example4  
+
 
−
press Enter.  
+
Type the command: $ ls space -l space example4. Press Enter.  
 +
 
 
|-
 
|-
 
|10:57
 
|10:57
 
|Here we can see the group permission is for user shahid.  
 
|Here we can see the group permission is for user shahid.  
 +
 
|-
 
|-
 
| 11:03
 
| 11:03
 
| To change the group permission, type the command: $ sudo space chgrp space rohit space example4
 
| To change the group permission, type the command: $ sudo space chgrp space rohit space example4
 +
 
|-
 
|-
 
|11:20
 
|11:20
−
|press Enter.  
+
|Press Enter. Enter the sudo password if required.  
−
Enter the sudo password if required.  
+
 
 
|-
 
|-
 
| 11:27
 
| 11:27
−
| Now type the command: $ ls space -l space example4  
+
| Now type the command: $ ls space -l space example4. Press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
|11:38
 
|11:38
 
|Here, we can see that the group has changed from shahid to rohit.  
 
|Here, we can see that the group has changed from shahid to rohit.  
 +
 
|-
 
|-
 
| 11:46
 
| 11:46
 
| The 'inode number' is a unique integer assigned to the device.
 
| The 'inode number' is a unique integer assigned to the device.
 +
 
|-
 
|-
 
|11:51
 
|11:51
 
| 'Inode' stores basic information about a regular file or a directory.  
 
| 'Inode' stores basic information about a regular file or a directory.  
 +
 
|-
 
|-
 
|11:57
 
|11:57
 
|All the files are hard-links to inodes.  
 
|All the files are hard-links to inodes.  
 +
 
|-
 
|-
 
|12:00
 
|12:00
 
|Whenever a program refers to a file by name, the system actually uses the filename to search for the corresponding 'inode'.  
 
|Whenever a program refers to a file by name, the system actually uses the filename to search for the corresponding 'inode'.  
 +
 
|-
 
|-
 
| 12:12
 
| 12:12
 
| We can use 'ls space -i' command to see the 'inode number' of a file.  
 
| We can use 'ls space -i' command to see the 'inode number' of a file.  
 +
 
|-
 
|-
 
|12:19
 
|12:19
−
|Type the command: $ ls space -i space example5  
+
|Type the command: $ ls space -i space example5. Press Enter.  
−
press Enter.  
+
 
 
|-
 
|-
 
|12:29
 
|12:29
 
|Number written before the file is the 'inode number' of the file.  
 
|Number written before the file is the 'inode number' of the file.  
 +
 
|-
 
|-
 
| 12:35
 
| 12:35
 
| 'Inodes' are associated with precisely one directory at a time.  
 
| 'Inodes' are associated with precisely one directory at a time.  
 +
 
|-
 
|-
 
|12:41
 
|12:41
−
|Hard-links are to associate multiple directory entries with a single inode.  
+
|Hard-links are to associate multiple directory entries with a single inode. '''ln''' is the command to make link.  
−
'''ln''' is the command to make link.  
+
 
 
|-
 
|-
 
| 12:52
 
| 12:52
 
| The syntax of '''ln''' command to create the hard-link is:  
 
| The syntax of '''ln''' command to create the hard-link is:  
 +
 
|-
 
|-
 
|12:57
 
|12:57
 
|ln space source space link where 'source' is an existing file and 'link' is the file to create.
 
|ln space source space link where 'source' is an existing file and 'link' is the file to create.
 +
 
|-
 
|-
 
| 13:06
 
| 13:06
 
| Now we will look at some examples of hard-links.  
 
| Now we will look at some examples of hard-links.  
 +
 
|-
 
|-
 
|13:10
 
|13:10
−
|Let me clear the screen again. Now type the command:  
+
|Let me clear the screen again. Now type the command: $ ln space example1 space exampleln press Enter.  
−
$ ln space example1 space exampleln press Enter.  
+
 
 
|-
 
|-
 
| 13:25
 
| 13:25
−
| To display the 'inode number' of both the files, type the command:  
+
| To display the 'inode number' of both the files, type the command: $ ls space -i space example1 space exampleln press Enter.
  
−
$ ls space -i space example1 space exampleln
 
−
press Enter.
 
 
|-
 
|-
 
|13:41
 
|13:41
 
|Here we can see that 'inode number' of both the files are same, file 'exampleln' is the '''hard link''' for file 'example1'.  
 
|Here we can see that 'inode number' of both the files are same, file 'exampleln' is the '''hard link''' for file 'example1'.  
 +
 
|-
 
|-
 
| 13:54
 
| 13:54
 
| '''Soft link''' '''symbolic link''' is a special type of file that contains a reference to another file or directory in the form of an '''absolute''' or '''relative path'''.  
 
| '''Soft link''' '''symbolic link''' is a special type of file that contains a reference to another file or directory in the form of an '''absolute''' or '''relative path'''.  
 +
 
|-
 
|-
 
| 14:07
 
| 14:07
 
| The syntax of '''ln''' command to create soft-links is:  
 
| The syntax of '''ln''' command to create soft-links is:  
 +
 
|-
 
|-
 
|14:12
 
|14:12
 
|ln space -s space {target-filename} space {symbolic-filename}  
 
|ln space -s space {target-filename} space {symbolic-filename}  
 +
 
|-
 
|-
 
| 14:19
 
| 14:19
 
| Now we will look at some examples of soft-link.  
 
| Now we will look at some examples of soft-link.  
 +
 
|-
 
|-
 
| 14:25
 
| 14:25
−
| To create the soft-link, type the command:  
+
| To create the soft-link, type the command: $ ln space -s space example1 space examplesoft  
−
$ ln space -s space example1 space examplesoft  
+
 
 
|-
 
|-
 
|14:40
 
|14:40
 
|press Enter.  
 
|press Enter.  
 +
 
|-
 
|-
 
| 14:43
 
| 14:43
−
| Now, to display the inode-number and list of both the files, type the command:  
+
| Now, to display the inode-number and list of both the files, type the command: $ ls space -li space example1 space examplesoft  
−
$ ls space -li space example1 space examplesoft  
+
 
 
|-
 
|-
 
|15:01
 
|15:01
 
|press Enter.  
 
|press Enter.  
 +
 
|-
 
|-
 
|15:03
 
|15:03
 
|Here we can see that inode-number of both the files are different and 'examplesoft' is a soft-link of example1.  
 
|Here we can see that inode-number of both the files are different and 'examplesoft' is a soft-link of example1.  
 +
 
|-
 
|-
 
| 15:16
 
| 15:16
 
| So, in this tutorial, we have learnt about the '''Linux Files Attributes''' like changing permission, ownership and group of a file.  
 
| So, in this tutorial, we have learnt about the '''Linux Files Attributes''' like changing permission, ownership and group of a file.  
 +
 
|-
 
|-
−
|15:26
+
| 15:26
 
|We also learnt about the '''inode''', '''soft''' and '''hard links''' of a file.
 
|We also learnt about the '''inode''', '''soft''' and '''hard links''' of a file.
 +
 
|-
 
|-
 
|15:31
 
|15:31
 
| This brings me to the end of this tutorial.  
 
| This brings me to the end of this tutorial.  
 +
 
|-
 
|-
 
|15:35
 
|15:35
 
|Spoken Tutorials are a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT.  
 
|Spoken Tutorials are a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT.  
 +
 
|-
 
|-
 
|15:44
 
|15:44
 
|More information on the same is available at the following link.
 
|More information on the same is available at the following link.
 +
 
|-
 
|-
 
|15:50
 
|15:50
 
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Latest revision as of 16:58, 23 March 2017

Time Narration
00:00 Welcome to this spoken tutorial on Linux File Attributes.
00:05 The prerequisites for this tutorial is to create empty files named as example1, example2, example3, example4, example5, and testchown.
00:18 Please create empty directories named as test_chown and directory1 also.
00:25 A file attribute is metadata that describes or is associated with a computer file.
00:33 File attribute is the characteristics that describes a file such as owner, file type, access permissions etc.
00:45 'c-h own' command is used to change the ownership of the file or directory. This is an admin command, root user only can change the owner of a file or directory.
01:00 The syntax of chown command is chown space options space ownername space filename or directoryname
01:13 We may give following options with chown command.
01:18 -R : To change the permission on files that are in the sub-directories of the directory that you are currently in.
01:28 -c : Change the permission for each file.
01:33 -f : Prevents chown from displaying error messages.
01:37 Now we will look at some examples.
01:40 So, go to the terminal. We will move to the directory where we have created empty files and folders. For that, cd space Desktop slash file attribute and press Enter.
01:56 Now type the command: $ ls space -l space testchown that is t-e-s-t-c-h-o-w-n and press Enter.
02:11 Here we can see the owner of the file 'testchown' is shahid.
02:18 To change the owner of the file, type the command: $ sudo space c-h own space that is a-n-u-s-h-a anusha space testchown that is t-e-s-t-c-h-o-w-n

Press Enter.

02:36 Enter the sudo password and press Enter again. Press Enter.
02:44 Now, type: $ ls space -l space t-e-s-t-c-h-o-w-n and press Enter. Here we can see the new owner of the file is anusha.
03:03 Now we will see how to change owner of the directory.
03:07 Type the command: $ ls -l and press Enter. Here we can see the owner of the directory 'test_chown' is shahid.
03:21 To change the owner of the directory, type the command:
03:26 $ sudo space chown space minus capital R space a-n-u-s-h-a anusha space test_chown which is directory name and press Enter.
03:44 Enter the sudo password if required and press Enter again.
03:49 I will clear the screen by pressing Ctrl+L for our convenience. Now type: $ ls space -l and press Enter.Here we can see the new owner of the directory is anusha.
04:06 chmod command is used to change the access mode or permissions of one or more files.
04:13 Syntax of the chmod command is chmod space [options] space mode space filename We may give the following options with chmod command.
04:29 -c : Print information about files that are changed.
04:34 -f ': Do not notify user of files that chmod cannot change.
04:41 There are following types of access or permissions:
04:44 r : Read, w : Write, x : Execute, s : Set user (or group) ID
04:54 Alternatively, we may specify permissions by a three-digit octal number.
05:00 The first digit stands for owner permission, the second stands for group permission, and the third stands for others permission.
05:09 Permissions are calculated by adding the following octal values: 4 that is Read 2 that is Write 1 that is Execute
05:20 Now we will look at some examples of chmod. Move to terminal and enter the command to add execute-by-user permission to file 'example1'.
05:30 Before that, I will again clear the screen by pressing Ctrl+l.
05:36 Now, let's type: $ chmod space u+x space example1 press Enter.
05:49 Now type: $ ls space -l space example1 press Enter to see the changes.
06:01 Here you can see, to assign the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.
06:15 Now type the command: $ chmod space 751 space example1 press Enter.
06:26 Now type: $ ls space -l space example1 and press Enter.
06:35 Here we can see that above command has assigned the read/write/execute permission by owner, read/execute permission by group, and execute-only permission by others to file example1.
06:52 To assign read-only permission to file example1 for everyone, type the command: $ chmod space =r space example1

and press Enter.

07:08 Now type the command: $ ls space -l space example1 press Enter.
07:19 Here we can see that the 'read only' permission has been assigned to file example1 for everyone.
07:30 To change the permission recursively and assign the read and execute access for everyone and also write access for the owner of the directory 'directory1', type the command:
07:44 $ chmod space minus capital R space 755 space directory1. Press Enter.
08:00 Now type: $ ls space -l press Enter to see the changes.
08:09 To give the user execute permission on file example2, type the command: $ chmod space u+x space example2 press Enter.
08:27 Now type the command: $ ls space -l space example2 and press Enter.
08:40 Here we can see that execute permission has been assigned to user on 'example2'.
08:50 To add the write permissions to the group for file example3

type the command: $ chmod space g+w space example3. Press Enter.

09:10 and now type: $ ls space -l space example3 press Enter.
09:23 Here we can see the write permission has been added to group.
09:30 To remove the write permissions for all, type the command: $ chmod space a-w space example3

Press Enter.

09:45 Now, type: $ ls space -l space example3 press Enter.
09:55 Here we can see the write permission, for all, has been removed.
10:02 chgrp command is used to change the group of one or more files to new group.
10:10 New group is either a group ID number or a group name located in /etc/group.
10:20 Only the owner of a file or a privileged user may change the group.
10:26 The syntax for the chgrp command is chgrp space [options] space newgroup space files.
10:36 Let's go to terminal. Now we will look at some examples of chgrp command.

Type the command: $ ls space -l space example4. Press Enter.

10:57 Here we can see the group permission is for user shahid.
11:03 To change the group permission, type the command: $ sudo space chgrp space rohit space example4
11:20 Press Enter. Enter the sudo password if required.
11:27 Now type the command: $ ls space -l space example4. Press Enter.
11:38 Here, we can see that the group has changed from shahid to rohit.
11:46 The 'inode number' is a unique integer assigned to the device.
11:51 'Inode' stores basic information about a regular file or a directory.
11:57 All the files are hard-links to inodes.
12:00 Whenever a program refers to a file by name, the system actually uses the filename to search for the corresponding 'inode'.
12:12 We can use 'ls space -i' command to see the 'inode number' of a file.
12:19 Type the command: $ ls space -i space example5. Press Enter.
12:29 Number written before the file is the 'inode number' of the file.
12:35 'Inodes' are associated with precisely one directory at a time.
12:41 Hard-links are to associate multiple directory entries with a single inode. ln is the command to make link.
12:52 The syntax of ln command to create the hard-link is:
12:57 ln space source space link where 'source' is an existing file and 'link' is the file to create.
13:06 Now we will look at some examples of hard-links.
13:10 Let me clear the screen again. Now type the command: $ ln space example1 space exampleln press Enter.
13:25 To display the 'inode number' of both the files, type the command: $ ls space -i space example1 space exampleln press Enter.
13:41 Here we can see that 'inode number' of both the files are same, file 'exampleln' is the hard link for file 'example1'.
13:54 Soft link symbolic link is a special type of file that contains a reference to another file or directory in the form of an absolute or relative path.
14:07 The syntax of ln command to create soft-links is:
14:12 ln space -s space {target-filename} space {symbolic-filename}
14:19 Now we will look at some examples of soft-link.
14:25 To create the soft-link, type the command: $ ln space -s space example1 space examplesoft
14:40 press Enter.
14:43 Now, to display the inode-number and list of both the files, type the command: $ ls space -li space example1 space examplesoft
15:01 press Enter.
15:03 Here we can see that inode-number of both the files are different and 'examplesoft' is a soft-link of example1.
15:16 So, in this tutorial, we have learnt about the Linux Files Attributes like changing permission, ownership and group of a file.
15:26 We also learnt about the inode, soft and hard links of a file.
15:31 This brings me to the end of this tutorial.
15:35 Spoken Tutorials are a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT.
15:44 More information on the same is available at the following link.
15:50 This script has been contributed by ----------------------(name of the translator) and this is -----------------------(name of the recorder) from --------------------------(name of the place)signing off . Thanks for joining.

Contributors and Content Editors

Minal, PoojaMoolya, Pratik kamble, Ravikala, Sandhya.np14

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