In the data file employees.dat we have employee records with the following fields of information (ID, FN, LN, D, #) where

ID: Employee identification number

FN: Employee first name

LN: Employee last name

D: Department

#: Office number

Write a shell script for processing employees.dat in such a way that we get the list of records (ID, FN, LN) and the total number of employees in the standard output as well as the file employees_by_office.dat that contains employee records with the following fields of information (#, ID, FN, LN, D). Records in the file employees_by_office.dat must be sorted by the key #, and fields are separated by the symbol :.