Chapter 11, Problem 40E

a.

Program Plan Intro

File protection mechanism in UNIX environment:

• In UNIX environment, the file protection is represented in the table format and consists of three rows and three columns as follows:

Operation	Owner	Group	World
Read	Yes	Yes	Yes
Write/Delete	Yes	Yes	No

Explanation:

From the above table,

• Each cell in the table represents the Boolean values.
• The Boolean value determines whether the file is to be read, write, or execute.
  • The Boolean value “Yes” specifies that the permission is granted to access the file.
  • The Boolean value “No” specifies that the permission is not granted to access the file.

Explanation of Solution

b.

Access to write/delete the file:

From the above table,

• It is known that the owner and list of users in a group are only allowed to write or delete the data from the file.
  • The Boolean value “Yes” is present only on the “Owner”, and “Groupp&#...

Explanation of Solution

c.

Access to execute the file:

From the above table,

• It is known that only the “Owner” is allowed to execute the data from the file.
  • The Boolean value “Yes” is present only on the “Owner” and ind...

Explanation of Solution

d.

Content of the file:

From the above table,

• It is known that only the “Owner” is allowed to execute the data from the file.
• So, the file must be an executable file.
  • The Boolean value “Yes” is present only on the “Owner” to perform execution operation in the file...