3. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file and no permissions to anyone else?

4. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file, read and write permission to group, and read permis- sion to other?

5. In UNIX, a file can be created by using a umask, which enables you to modify the default permissions for a file or directory. For example, a directory has the default per- mission of octal 777. If a UNIX administrator creates a directory with a umask of octal 020, what effect does this setting have on the directory? Hint: To calculate the solution, you can subtract the octal umask value from the octal default permissions