Last issue, we discussed a PDF editing tool kit for .Net servers. But what if you don't use a .Net-based system?We found two more promising products: Appligent's StampPDF Batch for Red Hat 7 & 9, Mac OS X, Windows NT\/2000\/XP and HP-UX; and PDF Tool's pdstamp, which is available for Win32 systems, Linux, Mac OS, Sun Solaris 2.6 - 2.9, IBM AIX 4.3, HP-UX 11.0, and FreeBSD 4.7.Both tools are command-line server applications that, no surprise here, stamp custom text and images into PDF documents. The stamping attributes are placed in text files that get passed to the applications.StampPDF also includes 32 Stamping Variables - variables that can be used to create stamping data - including file name, file path, file information, a variety of date\/time formats, page numbering and Bates numbers (a unique number, usually numerical, named after the Bates automatic numbering machine that used to be used to physically stamp documents).StampPDF pricing starts at $1,995. (Note that this company won't let you see its documentation unless you fill out a form. As Homer Simpson says: "Du'oh.")Pdstamp, while very similar in concept to StampPDF, is priced starting $375 for Win32 systems and $275 for Linux. PDF Tools also offers an extensive suite of PDF utilities.