NTFS implemented in Microsoft Windows NT and its derivatives, use ACLs[1] to provide a complex set of permissions.
There are four categories (system, owner, group, and world) and four types of access permissions (Read, Write, Execute and Delete).
[2] HFS, and its successor HFS+, as implemented in the Classic Mac OS operating systems, do not support permissions.
Beginning with version 10.4 ("Tiger"), it also supports the use of NFSv4 ACLs in addition to POSIX-compliant permissions.
The Apple Mac OS X Server version 10.4+ File Services Administration Manual recommends using only traditional Unix permissions if possible.
[5][6] IBM z/OS implements file security using RACF (Resource Access Control Facility)[7] The AmigaOS Filesystem, AmigaDOS supports a permissions system relatively advanced for a single-user OS.
In AmigaOS 1.x, files had Archive, Read, Write, Execute and Delete (collectively known as ARWED) permissions/flags.
OpenHarmony operating system alongside its client side ecosystem in Oniro OS and HarmonyOS with HarmonyOS NEXT versions and also Linux-based openEuler server OS natively uses its Harmony Distributed File System (HMDFS) that supports access token manager (role-based access control) and Core File Kit API capability-based with granular permission management with exception to openEuler.
[8][failed verification] Permissions on Unix-like file systems are defined in the POSIX.1-2017 standard,[9] which uses three scopes or classes known as owner, group, and others.
Each of the three characters represent the read, write, and execute permissions: The following are some examples of symbolic notation: In some permission systems additional symbols in the ls -l display represent additional permission features: To represent the setuid, setgid and sticky or text attributes, the executable character (x or -) is modified.
For the setuid or setgid attributes, in the first or second triad, the x becomes s and the - becomes S. For the sticky or text attribute, in the third triad, the x becomes t and the - becomes T. Here is an example: Another method for representing Unix permissions is an octal (base-8) notation as shown by stat -c %a.
However, when sharing files is desirable, the administrator can create a group containing the desired users, create a group-writable directory assigned to the new group, and, most importantly, make the directory setgid.