Module 2: Filesystem and Permissions

Lesson 1: Filesystem Hierarchy Standard (FHS)

1.1 Understanding FHS

1.1.1 What is FHS?

The Filesystem Hierarchy Standard (FHS) is a set of conventions for organizing the structure of directories in Unix-like operating systems, including Linux. It defines the purpose of each directory and the types of files they should contain.

1.1.2 Overview of Important Directories

/etc: System Configuration Files

Contains configuration files and directories used by the system and various applications.

/var: Variable Data Files

Holds variable data files such as logs, temporary files, and spool directories.

/home: User Home Directories

Home directories for individual users are located here, providing a personal workspace.

Lesson 2: File and Directory Permissions

2.1 Understanding File Permissions

In Linux, each file and directory has permissions that define who can read, write, and execute them. Permissions are represented by three groups: owner, group, and others.

• Read (r): Allows viewing the contents of a file or listing the files in a directory.

• Write (w): Permits modifying the file or adding, deleting, and renaming files in a directory.

• Execute (x): Grants the ability to execute a file or access a directory.

Permissions are denoted as a string of characters, such as rwxr-xr--, where the first three represent owner permissions, the next three represent group permissions, and the last three represent others' permissions.

2.2 Changing File Permissions

The chmod command is used to modify file permissions.

Symbolic Method:

chmod who_operator_permission file

Example:

chmod u+x file

Numeric Method:

 chmod 755 file

2.3 User and Group Ownership

chown: Change file owner and group.

chown user:group file

In this module, we've explored the Filesystem Hierarchy Standard (FHS) and gained an understanding of important directories such as /etc, /var, and /home. Additionally, we delved into file and directory permissions, covering the concepts of read, write, and execute permissions, and learned how to change permissions using the chmod command. We also explored the chown command for managing user and group ownership. These concepts are fundamental to effective Linux system administration and provide a solid foundation for managing and securing the file system.