File System Access Control List (FACL)
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Definition
A File System Access Control List is a set of permission rules attached to a file or folder that specifies which users or groups are allowed or denied actions such as read, write, modify, or execute. It is a common way operating systems enforce access control for stored data.
Examples
- A shared finance folder grants the Finance group read and write access, while all other users are denied access.
- A Linux file uses an extended ACL so one specific contractor can read a file without being added to the main group.
Discover 🔎
When you store data on a computer or file server, the system needs rules for who can access it. File System Access Control Lists are those rules. They are the reason one user can open a file and another user gets an access denied message. ACLs are a foundational part of access control because they translate policy into enforceable, system-level permissions.
Remember: An ACL is the rule list. The operating system checks the ACL every time someone tries to access the file or folder.
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