How can I print just one page or a few pages from a big document? How can I print pages in reverse order?

Try using a host-specific program, like the UNIX command psrev, which is part of the TranScript suite of software from Adobe Systems. Or use the more general utilities Ghostview, psutils or psxlate.

There is no guarantee that a given PostScript document can be split in such a manner. The reason is that some programs which generate PostScript code don't conform to the Adobe Document Structuring Conventions (DSC). (See Section 9, ``Encapsulated PostScript''.) A notable example of this is Microsoft Word.