3.1 Numeric mode

To use the symbolic mode, you need to first understand how the bits are represented in octal (base-8) numbers:

• 0001: execute (x) for other.
• 0002: write (w) for other.
• 0004: read (r) for other.
• 0010: execute (x) for group.
• 0020: write (w) for group.
• 0040: read (r) for group.
• 0100: execute (x) for user.
• 0200: write (w) for user.
• 0400: read (r) for user.
• 1000: sticky bit.
• 2000: set group ID.
• 4000: set user ID.

Using the symbolic mode, you can add up all the values representing the bits to be set. For example, the following comnand will allow all permissions to the user owner, read and execute only for the group owner, and no permission for others: