ACL Formats

ACLs have two basic formats:

Trivial ACL – Contains only entries for traditional UNIX user categories that are represented as owner@, group@, and everyone@.

For a newly created file, the default ACL has the following entries:

0:owner@:read_data/write_data/append_data/read_xattr/write_xattr
/read_attributes/write_attributes/read_acl/write_acl/write_owner
/synchronize:allow
1:group@:read_data/read_xattr/read_attributes/read_acl/synchronize:allow
2:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
:allow

For a newly created directory, the default ACL has the following entries:

0:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
/append_data/read_xattr/write_xattr/execute/delete_child
/read_attributes/write_attributes/read_acl/write_acl/write_owner
/synchronize:allow
1:group@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow
2:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
/read_acl/synchronize:allow

Non-Trivial ACL – Contains entries for added user categories. The entries might also include inheritance flags, or are ordered in a non-traditional way.

A non-trivial entry might look like the following example, where permissions are specifically granted to user Jan.
```
0:user:jan:read_data/write_data:file_inherit:allow
```