public final static void main( String[] args )
    {
        if( args.length < 3 ){
            usage("Not enough arguments.");
        }   // end if: args.length < 3
        else {
            String flag = args[0];
            String infile = args[1];
            String outfile = args[2];
            if( flag.equals( "-e" ) ){
                Base64.encodeFileToFile( infile, outfile );
            }   // end if: encode
            else if( flag.equals( "-d" ) ) {
                Base64.decodeFileToFile( infile, outfile );
            }   // end else if: decode    
            else {
                usage( "Unknown flag: " + flag );
            }   // end else    
        }   // end else
    }   // end main