ls -l purchases.dat payments.dat 
-rw-r--r-- 1 msaul msaul  82 2010-03-20 17:48 payments.dat
-rw-r--r-- 1 msaul msaul 159 2010-03-02 15:27 purchases.dat

cat purchases.dat 
A100:Annie Marie's Dance Academy:123:1500
F110:Frankies Repair Shop:1123:250
S100:Sandra's Counselling Service:67:500
A100:Annie Marie's Dance Academy:254:500

cat payments.dat
A100:Annie Marie's Dance Academy:123:750
A100:Annie Marie's Dance Academy:254:500

./makePayments.bash purchases.dat payments.dat 
MAIN MENU                                         # clear screen

1. Make a Vendor Payment
2. Display Vendor Purchases
3. Display Payments to Vendors
4. Exit

Please make a selection: 1
Enter the vendor number: F110                     # clear screen

Vendor Name: Frankies Repair Shop

1. Invoice #1123 Amount: 250

Please select transaction number: 1123
Enter Payment amount: 110.50
Payment transcation recorded.

Press <ENTER> to return to menu...
MAIN MENU                                         # clear screen

1. Make a Vendor Payment
2. Display Vendor Purchases
3. Display Payments to Vendors
4. Exit

Please make a selection: 3
Payments Report                                   # clear screen
================

Annie Marie's Dance Academy             $ 1250.00
Frankies Repair Shop                    $  110.50

Total Payments:                         $ 1360.50

Press <ENTER> to return to menu...
MAIN MENU                                         # clear screen

1. Make a Vendor Payment
2. Display Vendor Purchases
3. Display Payments to Vendors
4. Exit

Please make a selection: 4

# exit application and return to shell prompt