This command is used to extract the columns necessary for the matching engine from a data file that has extra information such as transaction numbers, etc. The only necessary information for the matching engine ultimately must take the form of five columns: 1) a date column, 2) a "side" column such as the word "buy" or "sell," 3) a symbol column, 4) a number of shares column, and 5) a total net proceeds column. Armed with this information in this column order, the matching engine can create the necessary results file. The reorder command simply takes an input file that likely will have several additional unecessary columns, and writes to an output file. The command takes a final parameter that is a list that represents the column placement in the input filefor the five items listed above. For example, the engine ultimately takes a first column that is the date of the transaction. However, if that information is the 11th column in your data file provided by your brokerage, you would start the list with 11. Then you would add a comma and the number of the column in the input file that has the side, etc.