orders_to_csv.py

#!/usr/bin/env python

import argparse


def parse_orders(fname, outname=None, encoding="Windows-1252"):

    if outname is not None:
        fout = open(outname, "w")

    with open(fname, encoding=encoding) as f:
        date = None
        check = None

        quantity = None
        item = None
        price = None

        for line in f:
            line = line.strip()
            tokens = line.split()

            # Date
            if len(tokens) >= 2 and tokens[0].startswith("Date"):
                date = tokens[1]

            # Check
            if len(tokens) >= 2 and tokens[0].startswith("Check"):
                check = tokens[2]

            if date is not None and check is not None:
                # Quantity, Item
                if len(tokens) >= 3 and tokens[1] == "X":
                    quantity = tokens[0]
                    if tokens[-1].startswith("$"):
                        item = " ".join(tokens[2:-1])
                        price = tokens[-1][1:]
                    else:
                        item = " ".join(tokens[2:])

            if len(tokens) >= 1 and tokens[0].startswith("$"):
                # Price
                price = tokens[0][1:]

            # Print output and reset
            if quantity is not None and item is not None and price is not None:
                out = f'"{date}","{check}","{quantity}","{item}","{price}"'
                if outname is not None:
                    fout.write(out + "\n")
                else:
                    print(out)
                quantity = None
                item = None
                price = None

            # Subtotal
            if len(tokens) >= 1 and tokens[0].startswith("Subtotal"):
                check = None
                date = None

    if outname is not None:
        fout.close()


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("-out", help="Specify an output file name", default=None)
    parser.add_argument("inp", help="Specify an input file to parse")
    args = parser.parse_args()

    parse_orders(args.inp, args.out)

From the command line, you can do:

python orders_to_csv.py -out output.csv input.txt