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Can "traditional unix permissions" conflict with or override ACL permissions in OSX? Are there cumulative effects between these or are "traditional permissions" ignored when ACL permissions are enabled?

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up vote 1 down vote accepted

If there is no matching ACL entry in OS X, then the Unix permissions are evaluated. If there is a matching entry, it does not evaluate the Unix permissions.

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On pretty much every *nix in existence (which includes OS X) ACLs on native filesystems supplement standard *nix permissions.

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Ok, just to be 100% clear, what you're saying is that if the unix permissions on a file are set to r--r--r--@, and the ACL permissions are set to -rw-rw-rw-@, no one will be able to write to this file? – user52429 Aug 27 '10 at 13:58
Those look like some mighty strange ACL permissions... – Ignacio Vazquez-Abrams Aug 27 '10 at 14:13
Sorry, those ACL permissions should not have been specified that way. I think I found the answer I was looking for though. – user52429 Aug 27 '10 at 14:20

To determine whether or not to allow an action, the [ACE] rules are considered in order. The first rule that is applicable to the current actor and action determines the decision, and no further rules are considered. If none of the rules apply, then the decision is determined by the traditional Unix file permissions.


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