1 Create a simple file and do ls -ltr to see the details of the files.
•touch simple.txt
•ls -ltr
Each of the three permissions are assigned to three defined categories of users. The categories are:
• owner
In Linux and Unix-like operating systems, every file and directory has an owner associated with it. The owner is typically a user, and this ownership information is a fundamental part of the file's permissions and access control.The owner of a file or directory has specific rights and permissions to that file or directory, which can include reading, writing, and executing, depending on the file's permissions. The owner is granted these permissions, and they can control who else (if any) can access the file.To view the owner of a file or directory in a Linux system, you can use the ls command with the -l (long) option, like this:
• chown
The chown command in Linux is used to change the ownership of files and directories. It allows you to change the user and group ownership of a file or a set of files. The basic syntax of the chown command is:
example:- sudo chown alex simple.txt
ls -ltr
• group
In Linux, a "group" refers to a collection of user accounts that are managed together for various purposes, such as file permissions and access control. Groups are used to simplify user management and provide a way to grant or restrict access to files, directories, and resources.Here are some common commands and concepts related to groups in Linux:Create a Group: To create a new group, you can use the groupadd command. For example:
to create and check group :-
• sudo groupadd <groupname>
• cat /etc/group
• chgrp
In Linux, the chgrp command is used to change the group ownership of files and directories. It allows you to modify the group associated with a particular file or set of files. Here's the basic syntax for the chgrp command:
• sudo chgrp friends simple.txt
• ls -ltr
• others
In Linux, "others" refer to anyone who is not the owner of a file or directory and not part of the group that owns it. The concept of "others" is essential in file permissions and access control. Linux file permissions are typically divided into three categories for access control:
• Owner: The user who owns the file or directory.
• Group: The group associated with the file or directory.
• Others: All other users who are not the owner or part of the group.
chmod
The chmod command in Linux is used to change the permissions (mode) of files and directories. It allows you to specify who can read, write, and execute a file or directory.
permissions: This is a combination of letters and symbols that represent the desired permissions. It consists of three parts:
• User (owner) permissions: u (user) + +/- (add/remove) + r (read) or w (write) or x (execute).
• Group permissions: g (group) + +/- + r or w or x.
• Others permissions: o (others) + +/- + r or w or x.
• Alternatively, you can use numeric values to represent permissions: 4 for read, 2 for write, and 1 for execute. Add these values together for each category (user, group, others) to set the permissions.
• file_or_directory: The file or directory for which you want to change the permissions.
2 Write an article about File Permissions
Understanding File Permissions in Linux: A Comprehensive Guide
When it comes to managing a Linux system, understanding and correctly setting file permissions is essential for maintaining security, access control, and the integrity of your files and directories. In this guide, we'll dive into the world of Linux file permissions, exploring how they work and how to use them effectively.
File Permission Basics
In the Linux operating system, each file and directory is associated with a set of permissions that define who can read, write, and execute them. These permissions are typically represented using a combination of symbols and numbers, and they are divided into three categories:
• Owner: This is the user who owns the file or directory. The owner has the most control over the file, with the ability to modify permissions and content.
• Group: A group is a collection of users. Files and directories can be assigned to a specific group, and members of that group inherit the associated permissions. This is a way to grant or restrict access to a set of users.
• Others: This category encompasses all users who are not the owner or part of the group. It represents the rest of the world.
Each of these categories can be assigned the following permission types:
• Read (r): Allows viewing the contents of a file or listing the files in a directory.
• Write (w): Permits modifying or creating new files within a directory and editing the file's content.
• Execute (x): Enables running a file as a program or entering a directory.
Access Control List(ACL)
Access control list (ACL) provides an additional, more flexible permission mechanism for list systems.
Access control list is a service which is used for providing special permission to specific users and group to particular directories and file
use of ACL
think of a scenario in which a particular user is not a member of group created by you but still you want to give some read or write access, how can you do it without making user a member of group, here comes in picture Access Control List.