Here it is a simple guide that shows how to convert .chm to .pdf files.

First of all, a little introduction:
CHM (Microsoft Compiled HTML Help) is a Microsoft proprietary online help format, that consists of a collection of HTML pages and an index and that is often used for software documentation
PDF (Portable Document Forma) instead probably doesn’t need any introduction, since everyone knows it. Anyway, PDF is a file format used to represent documents in a manner independent of application software, hardware, and operating systems. Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, and other information needed to display it.

 

After this breifly introduction, I’m gonna explain how to convert .chm to pdf filed.
You need to install the chm2pdf application, a phyton script that converts CHM files into PDF files.

chm2pdf supports batch conversion, command line, PDF security options, password protection and compression modes.

 

To install it, you just have to do this:
     sudo aptitude install chm2pdf

 

After that, you can use chm2pdf to convert .chm to .pdf files.

For example, if you have an unstructured HTML files inside the CHM file:
     chm2pdf –webpage my-file.chm

If you have a structured HTML files:
     chm2pdf –book my-file.chm

By default, the correspondent pdf file will be created with the same name of the chm file. If you want to change this beaviour, just use the option:
     — produces my-file.pdf

Of course, there are more options that you can use, about title, compression, table of contents … just check the man page