+ -y: In addition to -d, which specifies an absolute date, the -y switch
+ specifies an offset, in days. For example, "-y 15" would increment the
+ "pretend date" 15 days from whatever was specified by the -d switch
+ (or now, if no -d switch was given).
+
+ -n: When used with "-d" and/or "-y", specifies that invoices should be dated
+ with today's date, irregardless of the pretend date used to pre-generate
+ the invoices.
+