Difference between revisions of "Linux-Ubuntu/C2/File-System-in-Linux/English"

Title Slide

Learning Objectives

• Define Files, directories and inode.
• Create a file and add text in it.
• Create directories and
• Change and remove directories safely.

System Requirements

Ubuntu OS version 24 point 04.

Pre-requisites

To follow this tutorial,

Learners should know the basics of using the Linux terminal.

For the prerequisite Linux tutorials please visit

https://EduPyramids.org

• Learners should know the basics of using the Linux terminal.
• For the prerequisite Linux tutorials please visit this website.

Code files

The following code file is required to practice this tutorial

1. fs-commands.txt

This file is provided in the Code Files link of this tutorial page.

This file is provided in the Code Files link of this tutorial page.

Files

• In real life, a file is used to store documents and papers.
• Similarly, in Linux, a file is a container used to store information.

In Linux almost everything is treated as a file.

In real life, a file is used to store documents and papers.

Similarly, in Linux, a file is a container used to store information.

Directory

• A directory is a collection of files and other sub-directories.
• A directory helps us organize our files in a systematic manner.

A directory is a collection of files and other sub-directories.

A directory helps us organize our files in a systematic manner.

inode

inode.png

It has a name, creation, modification time and permission.

These properties are stored in a structure called inode.

An inode is a data structure identified by a unique number.

It is used by the system to identify a file.

It stores information about a file such as size, permissions, and ownership.

It also stores timestamps and the disk location of the file.

File name is only for human convenience.

A directory does not store files directly.

It is a file that maps file names to their corresponding inode numbers.

Linux File System hierarchy

Linux-filesystem.png

At the top of this tree is the root directory indicated by slash(/).

Every file and directory exists under root(/).

Types of Files

types-of-files1.png

Linux has three main types of files:

1. Regular files : They store data as a stream of characters.

For example: text files, images, videos.

1. Directories: Organize files and other directories.
2. Device files: These represent hardware such as disks, USBs, Cds.

They can be read and written like files.

Press Ctrl, Alt and T keys on your keyboard

Point to the output

/home/spoken

Let me type pwd and press Enter.

The output shows /home/spoken as the present working directory.

Terminal shows the following output.

• List of all files with file permissions,
• file owner's name,
• file size in bytes,
• last modification time,
• File or directory name.

ls -l >fileinfo and press Enter.

Observe that nothing is displayed on the screen.

cat fileinfo and press Enter.

So type cat space fileinfo and press Enter.

Output shows the file contents.

cat > file1.txt and press Enter.

It can also be used to create or append files.

Type cat space greater than file1 dot txt and press Enter.

Press Ctrl + D keys to end the input.

So let’s type I am creating a new file. and press Enter.

Whatever we type will be written into the file.

The input is ended by pressing Ctrl and D keys together.

cat >>file1.txt and press Enter.

cat space greater than greater than file1 dot txt and press Enter.

This is a new line in the file. and press Enter.

Press Ctrl + D keys together.

So type, This is a new line in the file. and press Enter.

Press Ctrl and D keys together to end the input.

cat space file1 dot txt and press Enter.

While recording, show the directory creation in the home directory.

Place the terminal and home directory side-by-side.

To create a directory I will type mkdir space test1 and press Enter.

If no output appears it means that the command has executed successfully.

So I will type mkdir space test2 space test3 and press Enter.

Show the folders test4 and test4.1

Highlight -p.

This will create a directory test4 point 1 within the test4 directory.

Here the argument hyphen p creates parent directories if they do not already exist.

Then test4 point 1 directory is created inside test4.

We are now in the test1 directory.

So type cd space dot dot

Press the backspace key to erase the prompt.

All the directories with the name test will be displayed.

Press the backspace key to erase the prompt.

Press the Enter key.

Let me type cd space dot dot slash dot dot slash

Here the first two dots move up one level.

Second two dots moves up one more directory level.

Press the Enter key.

Type rmdir space test1 and press Enter.

Now, we can see that the test1 directory is removed.

Highlight the output: rmdir: failed to remove 'test4': Directory not empty

The output shows

rmdir: failed to remove 'test4': Directory not empty.

This indicates that if the directory is not empty it cannot be deleted.

A directory must be empty before it can be removed using rmdir.

Summary

In this tutorial we have learn to:

• Define Files, directories and inode
• Create a file and add text in it
• Create directories and
• Change and remove directories safely

Assignment

• Create a file named myfile using the cat command
• Write one line of text in it.
• Display the contents of myfile using the cat command.
• Create a directory named mydir and create sub-directories inside it.

Thank you

Thank you.