A script file reads rows from its standard input (stdin) and writes rows to its standard output (stdout). Each input row to the script file is sent as a string with the column values separated by the delimiter specified in the DELIMITER clause. If no DELIMITER clause is specified, the default is a tab. Each input row is separated from the next by a newline character.
The result of the script file must also be a delimited string and the values are converted back to data types specified in the RETURNS clause. Each output row must separated from the next by a newline character (\n).
Nulls are represented as empty strings. For example, the following example represents the input string for a row with three integer values where the last two are NULL (delimited by colons):
1::\n
The first value is 1, there is no value between the first and second delimiter, and no value between the second delimiter and the newline character. The input row is equivalent to (1, NULL, NULL).
If the return values from the script file are not in a delimited string format, the script execution fails.