 that are shown files and directories in Linux. So, these are the learning outcomes. At the end of this session, students will be able to demonstrate the file and the directories permission in the Linux. So, we will start with the file management. As we know that the file management system is the set of the system software that provides a service to user and application in use of files. So, in this video, first we will discuss about the file management in the Linux. All the data in the Linux is organized into files. All files are organized into directories. So, these directories are organized into the tree-like structure called the file system. So, when you are working with the Linux the one way or the another you will spend most of the time working with this file. So, in this video we will see how the users can create and remove the files, directories, change permission of the files and directories etc. So, these are the hierarchical file system in which the first the root is shown here means under the root there are the sub directories or the files in the Linux system. Now, we will discuss with the three types that are the files which have in the Linux. Basically, there are three types of files ASCII files, directory files and the device file. So, now consider what are the ASCII files? So, this is the most common type of the file found on the most of the system. It is the sequence of characters or bytes for example of this file would be the source code file or executable files or binary files. To the Linux operating system there is a no difference between the text file or the binary file. Both are the stream of the bytes divided up to the blocks and stored on the filling system. Next we will see that is the directory files. A directory is a special type of the files. It is the file soft file. This type of file does not contain any text or executable programs but a list of file names and the directory names and other related information such as location on the storage device size of the file and their ownership. Next is the device file. The Linux provide the standard interface between the hardware such as disk printers and the operating system. Means all input and output on the Linux system is handled through this of this file. The computer terminal as far as the Linux operating system is concerned is a file. So, now moving we will see the access mode in the files and the directory. So, in the file so there are three access mode that is read write and executable. So, when there is only the read permission so it grants the capability to read just view the content of the file. You cannot modify the content of the file. Next one is the write that is grant is a capability to modify or remove the content of the file. Means you can modify the file or the directory inside whatever the data is there. Next one is executable. User can execute the permission that can run the file as a program. Similarly, if you see that is the access mode to the directory mode also there are three types that is read write and execute. Read write and execute. The user can read the content and can look at the file names inside the directory. So, such type is the read access mode. So, write mode the user can add or the delete files of the content of the directory executable. The user must have the execute access to the bin directory in order to execute or the command. Next, we will see the file directory permissions. So, now if you want to change the permissions of the file from read to write or write to executable or any other form that is executable to the just read file. So, there are some conditions are there in the Linux. So, we will discuss about the file permission and the access mode in the Linux. Every file in the Linux has the following structures. That is owner permission, group permission and other world that is the permissions are there. So, in owner permission, the owner permission determines the what actions the owner of the file can perform on the file. Group the same way as same as in the owner, the group will has the permission to determine what the actions a user who is a member of that group that a file belongs to that can perform on the file. And other world permissions are nothing but the permission of the others indicate what actions all other users can perform on the file. Next, you can have the changing permissions of the file. To change the file of the directory permissions, you can use the chmod that is a change mode command. There are two ways of to change more that is a symbolic mode or the absolute mode. So, by seeing the symbolic mode, by seeing the symbolic mode, the easiest way to the beginner is to modify the file or the directory permission is to use the symbolic mode. With the symbolic mode permissions, you can add, delete or specify the permission sets by you want by using the operators in the following table. Now, suppose if you want to add the selected permission to the file directory, then you have to make use of an plus sign. Next, if you want to remove the permission of the file of the directory, then you have to make use of an minus sign equals is a set of selected permissions. In the similar manner, if you want to make use of an the absolute permission, that is a second way to modify the permission of the file, the ch command is to number specify the each set of the permission for the file. Each permission is assigned a value for the following table, as shown in the below. The total of each set of the permission provides the number of for that set. That is for example, if no permission is there, then is minus minus minus is there for the reference. If you want to give the execute permission, then it is given by donated by X. If it is has the right permission, then it is denoted by W. If it is have only the read permission, it will be have R. If the file contains all the read, write and executable, it will show in the RWX. So these are the file containing. So last time we have seen how to use the terminal now. So in the in the first slide, we have seen that. So how you are going to change or the directory or you can make the directory also you can create the file by using the terminal, we will see the live demo now. So just we'll switch on to the terminal which is there in the Linux you want to. So this is the terminal which is used in the Linux. So when we open the terminal, we have to change the user from the normal user to the super user if you want to change the permission of the file here. So for that reason, so first is command is to set by changing the super user is so that is the super user. So now you can have the root. So you have all the privilege right to change the file permission unless and until you don't have the root permission, you don't you are not allowed to change the file name. So first we'll see how many files or the directories are there on the desktop here or on the root folder here. So for that, there is one Alice command is there. So these are the files are there analog example music. So these are the folders which are there in the blue and which are the executable files are there. So which are on the green and these are the white files are there. So that is an the text files are there. So to differentiate between the directories and files. So we are going to have such type of colors here. So now if you want to go into an desktop there, so we have to type the CD and it is a case in situ we have to type it. So we'll go to the desktop folder. So now you are going to an desktop folder LS if you list all the files, there are no files on the desktop. So that's why it is showing the zero files on the desktop here. So after that, we can create the new file by using the command touch. So to see as touch file one dot C, if you type this, so the touch file has been created on the desktop folder. If you want to see, then you have to make it the command that is an LS. So the file dot C has been created. So if you want to see what are the contents are there in the files, so you can make it use of cat command that is file. So just you make it tab you will go to that file. So there is no content in there. If you want to modify that file, if you want to write the data, then there is one more command nano file. So it will open the terminal. So where you can have hello everyone. If you want to save control x y just so if you want to see what we have done there, so just go to the cat command file. So you'll see hello everyone here. So now in the same manner, if you want to create the directory, then you can make it by the command m d i r i c t. So it will be make directory. So if you don't LS, so as shown in the previous, it will show in the blue because it is in directory form and it is in file. So if you want to go into that, you have to change directory i c t LS. So there are no files inside this here. If you want to remove that directory, then is one more command remove i c t folder that is it will be removed here. So no such file or directory is there because you have to change that directory. Just we have to come out from the directory. Now you can use remove directory. So if you have seen, so there is no file here. So here i c t is there. Here no i c t folder is formed. So now we'll see now how to change the permission of an file or the directory. So for that we have seen the command that is c h m o d triple seven means if you are going to see the absolute that is the you have to give the number triple seven means you can have read write and execute permission to that file. So now you have changed the file permission here. So you can change the file permission. So we if you are seen LS, so we'll see in the file dot c which has been ready to execute read and write here. So these are the basic commands you have to remember while you are going to do with the files that is the touch file to create the new file cat to see the inside whatever the file contents are there nano to modify the files make directory or the remote directory or if you want to change the permission of the files you can have the change mode command here. You tell the difference between the cat command and the touch command. So the touch command is used to create the new file with the size zero and the cat command is used to see what are the contents are there inside the file. So these are the my references. Thank you.