How to open PDF raw?

Question

I\'ve been wanting to see the insides of a PDF for a while, like, the raw source code of it so I can look at it. Any way of doing that?

Answer 1

Looking at the raw code of PDFs will not serve you much unless you also have an idea about its internal structure. You should get yourself a copy of the official PDF reference (download PDF), and you should have read some introductionary article such as this [gone] or this to begin with.

Even after such a preparation, you'll not discover much useful when staring at the raw code. Because PDFs usually will contain parts which are "filtered" (that means: compressed).

How to look at the real PDF source behind the 'raw' binary parts

Jay Birkenbilt's qpdf is a very useful commandline tool (available for Linux, Mac OSX and as source code, under the open source Artistic License), which can unpack most filtered content and re-organize the internal structure in a way that gives you much more insight into it (all objects are numerically ordered, etc.). The commandline to achieve this is:

 qpdf  --qdf  original.pdf  unpacked.pdf

Another useful and free tool (GPL licensed, but Linux-only AFAIK) to look into PDFs is of course PDFEdit. This one even comes with a GUI (if you prefer that), while still allowing you access to the internal structure and "raw" PDF code.