Apple Mac OS X Server Using chmod to Modify ACLs, To grant a user write permission for a file

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Using chmod to Modify ACLs

Using chmod, you can add and delete ACEs for a file or a folder. Here are a few of the parameters to be used with ACLs:

Parameter	Description
+a	Adds an entry to the ACL
+ai	Adds an inherited entry
-a	Removes an entry from the ACL

The following are some of the common permissions you can assign to files:

Permission	Description
delete	Grants permission to delete the item
readattr	Read an object’s basic attributes
read	Read the object
write	Write to the object
writeattr	Write an object’s basic attributes
readextattr	Read extended attributes
writeextattr	Write extended attributes
readsecurity	Read an object’s extended security information (ACL)
writesecurity	Write an object’s security information (ACL)
chown	Change an object’s ownership

The following are the permissions applicable to folders:

Permission	Description
list	List entries
add_file	Add a file
add_sudirectory	Add a subfolder
delete_child	Delete an object

To grant a user write permission for a file:

Enter the following command, replacing user1 with the name of the user you are granting permission to and file1 with the name of the file:

$ chmod +a "user1 allow write" file1

To deny a guest read permission for a file:

Enter the following command, replacing file1 with the name of the file:

$ chmod +a "guest deny read" file1

Chapter 9 Working with File Services