File Ownership and Security

Three groups of users can access files: owner, group, and other. File access is divided into three types of permissions: read, write, and execute.

Who Has Access?

The three basic classes of users are:

Owner - Usually the person who created the file.
Group - Users that have been grouped together by the system administrator. For example, the members of a department might belong to the same group.
Other - All other users on the system.

Types of Access Permissions

The access permissions on a files specify how that file can be accessed by the owner, members of the group, and other users.

Read Permission - Allows access to retrieve, copy, or view the contents of the object.
Write Permission - Allows access to change the contents of the object or remove the object.
Execute Permission - For a file, allows access to run the file (for executable files, scripts, and actions). For a folder, allows access to run commands, scripts, and actions within that folder.

If you do not have permission to write inside a folder, the folder's icon will look like this:

If you do not have read or execute permission for a folder, the folder's icon will look like this:

Examples

To make a folder private:

Change the folder's properties, giving yourself (the owner) read, write, and execute permission, but giving no permissions for group and other. This means that only you and the root user can view the contents of the folder.

To make an object that you've created available for everyone to use but protect it so it isn't inadvertently overwritten:

Change the file's properties, giving read and execute permission to owner, group, and other. Don't give anyone write permission.

Default Permissions

The default permissions used when you create a new file or folder may be altered by your system administrator. To determine what your current defaults are, create a new file or folder, then open the Permissions dialog box for that file or folder.

Check with your system administrator regarding how to change your default permissions.

To Change the Owner of a File or Folder

You must be the owner or the system administrator (root user) in order to change the ownership of a file or folder.

Select the object's icon.
Choose Change Permissions from the Selected menu or from the object's pop-up menu (displayed by pressing Shift+F10 or the right mouse button).
Type the new owner's name into the Owner Name text field.
Click OK or press Return.




	NOTE: If you give ownership of the file to another user, you may not be able to change the permissions again unless that user returns ownership to you.

If you do not have permission to change the properties, some of the controls in the Permissions dialog box are unavailable.

To Change the Permissions on a File or Folder

You must be the owner or the system administrator (root user) in order to change the permissions of a file or folder.

Select the icon for the file or folder.
Choose Change Permissions from the Selected menu or from the icon's pop- up menu (displayed by pressing Shift+F10 or the right mouse button).
Select the permissions for the file or folder.
The permissions selected in the Group row indicate the access privileges for any user belonging to the named group. The permissions selected for the Other row apply to all other users.
Read
The file can be read
Write
The file can be altered
Execute
The file can be run
If you give ownership of the file to another user, you may not be able to change the permissions again unless that user returns ownership to you. If you do not have permission to change the properties, some of the controls in the Permissions dialog box are unavailable.
Click OK or press Return.




	NOTE: The Group row of permissions shows the permissions for users who are members of the group listed in the Group Name text field. You can specify a different group by typing a new name in this field.

File Ownership and Security

Technical documentation

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