By default Custom Addressbook stores all address data in the file address.dat or the file you last opened/saved through the main file menu. This file is in the same directory as the program itself. However, by specifying a command-line parameter the program can use another file. Always enclose the filename between double quotes (see the examples below).
addressbook "addr2.dat" (starts addressbook with the file addr2.dat which is in the same directory as the program) addressbook "c:\temp\address data\addr3.dat" (starts addressbok with the file addr3.dat which is in the directory "c:\temp\address data\").