File inclusion via FWEB’s ‘@i’ command suffers from a design deficiency: they cannot be inhibited by means of FWEB’s preprocessor commands. (The reason is that ‘@i’ is processed very early in the input stage, before tokenization. This design decision was inherited from CWEB, and is very difficult to change.) A particularly annoying situation arises when the same file is included multiple times; various array space may be eaten up unnecessarily. The ‘-j’ option inhibits such multiple includes.