OS X - Access Control Lists (ACL)

Contents

Background

Every modern operating system provides a more fine graded method of access control to operating system items then the classic Unix security which can provide read, write and execute permission to the three groups Owner, Group and Others. Mac OS X uses two types of permissions on files, file modes and Access Control Lists (ACLs).

Managing ACL's

The command s

chmod

-a
remove acl
+a
add acl
-a#
# specifies th rule which should be deleted or modified ACL command "user

ls -le

-e
show ACLs 

   ls -le  OSX-Acl.txt 
   -rw-r--r--+ 1 tuxi  staff  29 16 Aug 12:59 OSX-Acl.txt
    0: user:tuxi deny read,write
    1: user:tuxi allow append


area uesed to manage ACLs on OSX

Samples

Complete Sample of ACLs

In a shell type the following commands to test. 







   ls -le  OSX-Acl.txt 
   -rw-r--r--+ 1 tuxi  staff  58 16 Aug 13:06 OSX-Acl.txt
    0: user:tuxi allow append

Samples using chmod for ACLs

chmod 
 chmod +a "admin allow write" myfile.txt
 chmod +a "guest deny read" myfile.txt
 chmod +a "admin allow delete" myfile.txt
 chmod +ai "others allow read" myfile.txt
 chmod +a# 2 "others deny read" myfile.txt
 chmod -a# 1 myfile.txt
 chmod -a "admin allow write" myfile.txt
 chmod =a# 1 "admin allow write,chown"

Issues


Fixing "Finder wants to make changes" message


If the "Finder wants to make changes. Type your password to allow this." dialog appears when you attempt to move, rename, or delete files, it's likely incorrect permissions on your files have accidentally been set. More specifically, the Access Control Lists (ACLs) on the affected files causes the problem.
To correct the problem, you'll need to use the Terminal to remove the ACL from the problem file with the following command:
chmod -N filename

Status: Published Date: 2017/06/05 14:13:04 Revision: 1.1
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