Operating Systems
File Permissions
Definition
File permissions dictate who can read, write, and execute files. The operating system is responsible for enforcing these permissions to control access to data.
Why It Matters
Permissions are a fundamental aspect of security and multi-user systems. They prevent unauthorized users from accessing or modifying sensitive files.
Contextual Example
In a Linux system, the command `ls -l` shows permissions like `-rwxr-xr--`. This means the owner has read, write, and execute permissions (rwx), users in the group have read and execute permissions (r-x), and others have only read permission (r--).
Common Misunderstandings
- Incorrectly configured permissions are a common source of both security vulnerabilities and application errors (e.g., a web server not having permission to read its own files).
- The `chmod` and `chown` commands in Unix-like systems are used to change permissions and ownership.