KindleGen Usage

Download Kindlegen for Linux
Read publishing guidelines

Extract package anywhere

docs/english/Readme.txt content (relevant):

Creating Kindle ebooks - Advanced users:
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Advanced users can use the command line tool to convert EPUB/HTML to Kindle ebooks. This interface is available in Windows, Mac and Linux platform. This tool can be used for automated bulk conversions.

KindleGen for Linux 2.6 i386 :
1. Download the KindleGen tar.gz from www.amazon.com/kindleformat/kindlegen to a folder such as Kindlegen in home directory (~/KindleGen).
2. Extract the contents of the file to '~/KindleGen'. Open the terminal, move to folder containing the downloaded file using command "cd ~/KindleGen" and then use command "tar xvfz kindlegen_linux_2.6_i386_v2.tar.gz" to extract the contents.
3. Open the Terminal application and type ~/KindleGen/kindlegen. Instructions on how to run KindleGen are displayed.
4. Conversion Example: To convert a file called book.html, go to the directory where the book is located, such as cd desktop, and type ~/KindleGen/kindlegen book.html. If the conversion was successful, a new file called book.mobi displays on the desktop.
5. Please note: It is recommended to follow these steps to run KindleGen. Double-clicking the KindleGen icon does not launch this program. Run the above commands without quotes

Instructions on how to run KindleGen:
Navigate in terminal to folder
type ./kindlegen for usage information:

*************************************************************
 Amazon kindlegen(Linux) V2.9 build 0730-890adc2
 A command line e-book compiler
 Copyright Amazon.com and its Affiliates 2013
*************************************************************
Usage : kindlegen [filename.opf/.htm/.html/.epub/.zip or directory] [-c0 or -c1 or c2] [-verbose] [-western] [-o ]
Note:
   zip formats are supported for XMDF and FB2 sources
   directory formats are supported for XMDF sources
Options:
   -c0: no compression
   -c1: standard DOC compression
   -c2: Kindle huffdic compression
   -o : Specifies the output file name. Output file will be created in the same directory as that of input file. should not contain directory path.
   -verbose: provides more information during ebook conversion
   -western: force build of Windows-1252 book
   -releasenotes: display release notes
   -gif: images are converted to GIF format (no JPEG in the book)
   -locale : To display messages in selected language
      en: English
      de: German
      fr: French
      it: Italian
      es: Spanish
      zh: Chinese
      ja: Japanese
      pt: Portuguese
      ru: Russian

First impressions:
This program should be able to convert .html/.htm and .epub files...
it converts them to .mobi to a filesize at least double the original (depending on images and compression)
Uploaded to Kindle, all the files seem to work fine. Text formatting is kept in some way - not perfect, but readable. Kindle shows Title and author for the epub, and title set for the html (not filename!)

Seems okay, but I do not have a real chance to generate a beautiful book this way easily... maybe converting from epub might be a chance to keep the book beautiful...

...or should really read the  publishing guidelines to learn the proper formatting.