Welcome back friends. Throughout the course we have learned about various topics and learned a wide range of commands on our ETL environment. And here in this video we are going to learn about file system in depth and are more about what we can do with file system and what are the details is that we can gather for our solutions. So let's start we can create partitions on file systems. And the file system consists of various partitions that we have to understand. This drives are divided into various partitions the Linus drives are divided into partitions.

They are formed with file systems allowing user to store data with consisting of folders directories and various utilities. The default file system is called x 33. Which is fully formed l third extended to Mix file system. So, the file system was or whatever we say in the earlier slide earlier videos in the first three sections, the whole thing route home, etc, when and all the stuff like that, that is a file system. The default file system is a new version. The other common file systems are x 82 and MS DOS, which are typically used with floppies they are outdated.

So they are not used these days. ISO 9660 is typically used for CDs and GFS and GFS to is used for storage area networks or Sam. Then there is another concept called high node, I node is an entry in the table actually it is performed as an index node. It consists contain information about a file, which is a data about data All metadata about the file, the information the last created, edited the permissions and all information. It contains a list of all files in HD two or ESP three file system. It includes file type permission, user ID, group ID, the link count, which is a count of path names pointing to this file.

Multiple paths could point to the same file. In Linux, the file size and various timestamp timestamp is a unique moment of time which is recorded. We have hours minutes seconds followed by date and month. A timestamp is a certain point of time, which is unique. A time may differ from timezone throughout the world but timestamp is always the same. It It begins with the first formation of the database back in 90 70s and 80s till then, it is used as a common difference of time in databases these days also, it points to files data blocks or disk or other data about the files.

The directories are vital and file system that computers reference for a file is the ID number. The human way to refresh our file is by file name. A computer uses the inode number, but we use this file name because we could not remember a huge range of AI note number. However each eye note is assigned to a file name. Or directory is a mapping between the human name for file and a computer's AI note number. That is a visual representation.

Copy and I note Come on. I could we could work Here as the copy command or CP command, Allah allocates a free number, placing a new entry in the table. When we use this command, it creates a three inode number, a new one, placing a new entry in the inode table. It creates a D, D entry or directory entry. associating a name with the ID number, the name that we see it is actually what happens behind the curtain that we don't know actually. So if you want to understand how the system works, it is for you.

It copies data into the new file. These are the steps that the copy command follows. We simply write the CP command and we think everything is done. So what is actually being done here by the system is this. Then we have Move for move what happens exactly. If the destination of the move command is on the same file system as the sole the move command has to perform this task, it creates a new directory with this entry with the new file name and deletes the old directory entry with the old file name.

That's it. It has no impact on the inode table. It is simply the change of the difference. Only the timestamp is being changed not the table or the location of the data on that is no data is moved actually. The data is same at same place. Only the folder location or name or directory name is being changed.

If the direction is a different file system, move act as a copy and remove. cut and paste. RM What does RM Remove does it decremental encounter the spring I know number to be reused. Actually the when you delete a file, it deletes the link decrements the link counter and the inode number is free and it could be used for other files. It places data blocks on the free list the number which is free, it places on the free list that it is available for free. You could use it It removes the directory entry data is actually not actually removed, but will be overwritten when the data blocks are used.

So this is the thing that occurs on a system. When we delete. Actually nothing is being deleted, it is being overwritten or delete operation is an imaginary phenomena. That's why we can recover each and every file from a system Since when it was created, high was a huge chunk of system of files could be there. It could be hard if the file which is being deleted was a year or more than a year old. But we can recover that thing.

That's why over a time, address storage device like hard disk or pendrive, degrades, it could not be used. Because at a certain scale, the override operations could not be performed. And we need a new train. For hard links hard links are links that adds an additional D entry or directory entry to reference a single file. One physical file on the file system is there. Each directory references the same inode number.

It increments the link count the Remove command decrements the link count, remove command decrements the link cow and heartland incremental income to file exists as long as at least one link remains when you delete multiple links, that is a file being copied over different folders does not exist in different locations. Actually, different pointers or links are there. When you delete all the links, the file is being lost that difference is not there. Actually it is there. When the link count is zero the file is removed, theoretically, cannot expand drives or partitions. It could not expand overdrive.

Different partitions had different file if you create a copy or duplicate of the file in different partition, it will actually copy that file symbolic or soft link points to another file. ls minus l displays the link name and the first file as the file type one is for symbolic link. The content of a symbolic link is the name of the file that it references. There are seven fundamental file types. When we use the ls command list shell command, we have different file types. That is denoted by different alphabetic characters.

A regular file is represented by minus sign or dash, or directory is represented with a small d. a symbolic link is represented with a small L. A block a special file is represented with a small B. Character a special file is represented with a small C. A named pipe is represented with a small p, a socket or virtual port. represented with S. We can check free space and the system using the G VA utility or the command line with the GI utility we can move do so by moving with the applications system to use a disk usage analyzer. It will show you the free space and the use a space. You can defragment it and create your own thing. It has different options.

The d u produces text users report in kilobytes of the directory. It could be used to list the size of every file in the subdirectories by default, minus size and capital H options are used to display sizes and easier to read unit minus S is used to summarize the subdirectory and the money includes file system types. So, we can learn more and do an analysis over the file system and directories for removable media like pendrive CD drives and other drives this we have to do mounting and unmounting in Linux, when we insert a pendrive say pendrive on a system, we have to mount that printer to a particular location and when we remove we have to unmount it. So, what is the process that actually does some mounting integrates some foreign file system into the main tree. The pendrive contain can consist of different file system and the system consists of different file system as we have read x three or x 32 and different file system when the vendors file system has to be integrated In your systems, desktop environment or server environment, it has to be mounted.

However, in these days, auto mounting tools are there so you don't need to create a mounting location. Before accessing media must be mounted before they move in media must we unmounted this very simple thing in genome and Katie g y environment devices auto mount under media, they are automatically mounted in media location. If you're not using the UI mode, you have to specify the mounting location by commands as they are in console root can manually mount device there are two different methods, one for root and one for non root users. For root users, you have to provide a direct to the location Mount m&t. Then write these three commands. mk dir Create a device location within the mount then write the mount command for a particular location and when your work is done write the unmount command for the same location.

Similarly, for non root users, you can use the genome unmount command for unmounting and you know mount for mounting the file the directory will be same and you have to place the minus T and minus t arguments for CDs and DVDs, the same accessible from and they are ejected with right click eject. The USB media is handled with genome as we have learned. You can archive files or create a zip file, the zip or not actually zip zip rar identify, which is a shorter version or compressed format of the original file, archiving places, many file into one target file. It creates a single file, which consists of different files that are not executable until it has unzip. It has been unzipped. It is easier to keep backup because the size is less and the single file is there to store and transfer tar is a standard Linux archiving command.

We can use the tar command to create a archive and untagged to decompress archives are commonly compressed and algorithms applies that compressed file there are certain algorithms that are applied on compression uncompressing restores the original file, which are natively support the compression using the GZ organ If you can also use the Bz to all puns if there are various tools, various open source tools and things available online. Most of them are being archived in our and archive format either in tarball or new zip or other formats. There are various essentials or tar options that could be used. The actions which is required include minus c t and x. c creates an archive D creates a list of lists and archive. x extract the file from an archive. So you have to write these actions or options while creating as an archive file.

Typically, when you require archive names File after file archive, you can use F and there are optional of actions that can be used that for using the G zip compression j for PC to compression and V for verbose and x attribute that is to se line x and ACL properties. Sl n S is a security enhanced line x, which is being implemented by our HCl. The creating file archives you can use other tools as well. The format is being we have to write zip C'mon, set IP minus r, then provide the file name and the location then write unzip if you want to unzip the file with the extension dot zip under the file is here and read the file to Lackawanna Graphically you can do very easily without writing any color. So, that was a detail about file system. Now we know how move copy, remove and other commands are physically executed.

The concept is clear when your concepts are clear, you understand the operating system better than others. So you could administer it more preferably, you need to understand what is actually happening within the OS that we have done here. You should also explore some ethical hacking or system security utilities how they could be compromised, so, you should secure you must be aware of different type of attacks out there. The DoS attack DDoS attack for attack ping of death attack A taxi would explode if you are going to become a Server Administration Administrator, so keep learning keep moving ahead. We should have a bright future ahead