# PDFX

PDFX is A-Shell's "print to PDF file" subsystem, which consists of an entire set of GDI printing directives related to producing and post-processing PDF files. All of these commands begin with "//PDFX," followed by a key and then a value. For example, the following directive tells PDFX to overwrite the existing file if it exists:

//PDFX,Save.When.Exists,1



The most common function of PDFX is to produce PDF documents such as invoices and automatically email them to clients. PDFX includes a variety of email-related commands for that purpose.

The PDFX subsystem is documented in a separate help file which you can access from the A-Shell [downloads...documents](http://microsabio.com/documents/) page. Contact MicroSabio if you have questions or would like to add PDFX to your A-Shell license.