File System Questions Medium
File system permissions refer to the access rights or privileges assigned to files and directories within a file system. These permissions determine who can perform specific actions on a file or directory, such as reading, writing, executing, or modifying it.
In most operating systems, including Unix-like systems (e.g., Linux) and Windows, file system permissions are based on a set of three categories: owner, group, and others. Each category can have different levels of permissions assigned to it.
1. Owner: The owner is the user who created the file or directory. The owner has the highest level of control and can typically perform all actions on the file or directory, including reading, writing, executing, and modifying permissions.
2. Group: A group is a collection of users who share common permissions. The group permissions apply to all users who belong to that specific group. Group permissions allow multiple users to have the same level of access to a file or directory.
3. Others: Others refer to all users who are not the owner or part of the group. These permissions apply to everyone else who does not fall into the owner or group category.
File system permissions are usually represented using a combination of letters or numbers. The most common representation is the symbolic notation, which uses letters to represent different permissions:
- "r" represents read permission, allowing the user to view the contents of a file or list the contents of a directory.
- "w" represents write permission, allowing the user to modify or delete a file, as well as create, delete, or rename files within a directory.
- "x" represents execute permission, allowing the user to run a file as a program or access a directory.
These permissions can be assigned separately for the owner, group, and others, using a combination of letters. For example, "rwx" represents read, write, and execute permissions for a specific category, while "r--" represents read-only permission.
File system permissions are essential for maintaining security and controlling access to files and directories. They ensure that only authorized users can perform specific actions, protecting sensitive data and preventing unauthorized modifications or deletions.