The Unix File System: A Comprehensive Guide for Beginners and Pros

• Introduction

• Listing files and directories

• Creating and deleting files and directories

• Copying and moving files and directories

• Permissions and ownership

• Links and symlinks

• Conclusion

  Introduction

  The Unix file system is a hierarchical system that organizes files and directories into a tree-like structure. It is a powerful and flexible system that is used in a wide variety of operating systems, including Unix, Linux, and macOS.

  In this blog post, we will explore some of the most important commands used to manage the Unix file system. We will also learn about some of the key concepts of the Unix file system, such as permissions, links, and symlinks.

  Listing files and directories

  Web servers: Web servers use the Unix file system to store the web pages and other resources that are served to web browsers.

  Databases: Databases use the Unix file system to store database files, which contain the data that is stored in the database.

  The ls command is used to list the contents of a directory. By default, the ls command will list all of the non-hidden files and directories in the current directory. To list hidden files and directories, use the -a option.

    ls -a
  

  To list the contents of a specific directory, specify the path to the directory after the ls command.

    ls /tmp
  

  

  

  To list the contents of a directory in a long format, use the -l option. This will list information such as the file size, permissions, and date and time of modification.

    ls -l
  

  Creating and deleting files and directories

  The touch command is used to create a new file. If the file already exists, the touch command will update the timestamp of the file.

    touch myfile.txt
  

  The mkdir command is used to create a new directory.

    mkdir mydir
  

  The rm command is used to delete a file.

    rm myfile.txt
  

  The rmdir command is used to delete a directory.

    rmdir mydir
  

  Copying and moving files and directories

• The cp command is used to copy a file or directory. To copy a file, specify the source file and the destination file after the cp command. To copy a directory, specify the source directory and the destination directory after the cp command.

    cp myfile.txt mydir/myfile.txt
  

    cp -r mydir mynewdir
  

  The mv command is used to move a file or directory. To move a file, specify the source file and the destination file after the mv command. To move a directory, specify the source directory and the destination directory after the mv command.

    mv myfile.txt mydir/myfile.txt
  

    mv mydir mynewdir
  

  Permissions and ownership

  Every file and directory in the Unix file system has a set of permissions that determine who can read, write, and execute the file or directory. The permissions are divided into three categories:

  • Owner: The owner of the file or directory has the highest level of permissions.

  • Group: The group of the file or directory has the next highest level of permissions.

  • Other: The other users of the system have the lowest level of permissions.

You can use the chmod command to change the permissions of a file or directory.

    chmod 755 myfile.txt

The number 755 represents the following permissions:

• Owner: read, write, and execute

• Group: read and execute

• Other: read and execute

• more generally, the read command has an octal value of four, the write command has an octal value of two and the execute command has an octal value of one

You can use the chown command to change the ownership of a file or directory.

    chown myuser myfile.txt

This will change the ownership of the file myfile.txt to the user myuser.

Links and symlinks

A link is a special file that points to another file. When you access a link, the system will automatically access the file that the link points to.

To create a link, use the ln command.

    ln myfile.txt mylink.txt

This will create a link to the file myfile.txt named mylink.txt.

A symlink is a special type of link that points to a file or directory that may not exist. When you access a symlink, the system will check to see if the file or directory that the symlink points to exists. If it does not exist, the system will return an error.

To create a symlink, use the ln -s command.

    ln -s myfile.txt mysymlink.txt

This will create a symlink to the file myfile.txt named mysymlink.txt.

Conclusion

The Unix file system is a powerful and flexible system that is used in a wide variety of operating systems. By understanding the basic commands and concepts of the Unix file system, you will be able to manage your system files without the use of an operating system which will ease your work from constantly moving the mouse on your machine.