Specifications

128 Chapter 8 Managing User and Group Accounts
Mac OS X provides distinct permissions for these types of users:
 The owner of the item, who is usually the person who created the item
 Any member of the group assigned to the item by Mac OS X
 Any other user with access to the computer
These are the levels of permission:
 Read & Write, which allows a user to open the item to see its contents and change it.
 Read Only, which allows a user to open the item to see its contents, but not change
or copy the contents.
 Write Only, which makes a folder into a drop box. Users can copy items to the drop
box but cannot open the drop box to see its contents. Only the owner of the drop
box can open it to access items.
 No Access, which blocks access to the item so users can’t open the item, change its
contents, or copy its contents.
Viewing Permissions
Each security group is assigned a code that controls that group’s permissions:
 r (read) allows the user to see the item but not make changes.
 w (write) allows the user to see and make changes to the item.
 x (execute) allows the user to run scripts or programs.
 - (access) means access is turned off.
To view permissions for files and folders, enter the ls -l command. For each file or
folder listed, you see the permissions, owner and group name, and file or folder name.
Examples of permission settings:
Following are examples of permission settings:
 The following file (-) displays read, write, and executable permissions for owner (rwx),
group (rwx) and all others (rwx):
-rwxrwxrwx
 The following file (-) displays read, write, and executable permissions for owner (rwx),
and group (rwx), but no permissions for others (---):
-rwxrwx---
 The following file (-) displays read, write, and executable permissions for owner (rwx),
but no permissions for group (---) or others (---):
-rwx------
 The following file (-) displays read and write, but no executable permissions for
owner (rw-), group (rw-), and others (rw-):
-rw-rw-rw-