Write a Unix command for changing the file permissions rwxx--x of the file script_11.sh in such a way that the owner of the file can do everything and nothing other regular users of the system.

a.- Write the Unix commands in order to create a new user named user01 with permission of system administrator.

b.- Create the group named xproject and add the users user1, user02, user3. Create a shared directory xproject_documents in the home directory of user1, in such a way that all the members in the group xproject can read all the documents in the shared directory. Apply the least privilege rule for the configuration of the system.

c.- A regular user, user1 forgot the password, so as system administrator write a Unix command to create a new password for user1.

d. Set the system umask in order to get the permissions by default drwxr- -r- - for directories and -rw-r- -r- - for files.