When parsing a line for an argument, initial and trailing blanks are ignored. In addition, an argument field is delimited by a comma, or some of the special characters (particularly the comment, end of input, special delimiter characters). If an argument has no non-blank characters before a delimiter is reached, the argument is said to be an empty, null, or skipped argument. Conventionally, an empty argument is to be treated as indicating some default value. For example:
