FB2 converter to EPUB2, KEPUB, MOBI 7/8, AZW3

A complete rewrite of fb2mobi

Aims to be faster than python implementation and much easier to maintain. Simpler configuration, zero dependencies, better diagnostics and no installation required.

Russian WiKi and forum.

Essential differences:

no UI: use Libro or MyHomeLib
no XSL pre-processing (see document.transform configuration instead)
no XML configuration - use TOML, YAML or JSON format instead
no "default" external configuration, path to configuration file has to be supplied - always
no overwriting of configuration parameters from command line, options either specified in configuration file or on command line
slightly different hyphenation algorithm (no hyphensReplaceNBSP)
fixes and echancements in toc.ncx generation
go differs in how it processes images, it is less forgiving than Python's PILLOW and do not have lazy decoding (see use_broken_images configuration option)
small changes in result formatting, for example:
- chapter-end vignette would not be added if chapter does not have text paragraphs
- html tags unknown to fb2 spec may be dropped depending on context
- page size is calculated based on proper Unicode code points rather than byte size
- ...
full support for kepub format
processing of files, directories, zip archives and directories with zip archives - no special consideration is made for .fb2.zip files.
flexible output path/name formatting
fb2c could be build for any platform supported by go language. If mobi or azw3 are required additional limitations are imposed by Amazon's kindlegen
fb2c has no dependencies and does not require installation or any kind

Installation:

Download from the releases page and unpack it in a convenient location.

Starting with v1.60.1 macOS releases for Intel and Apple silicon are build separately. I do not have kindlegen for Apple Silicon - not sure if one even exists, so manage your expectations.
Starting with v1.58.0 releases are packed with zip and signed with minisign. Here is public key for verification:

RWTNh1aN8DrXq26YRmWO3bPBx4m8jBATGXt4Z96DF4OVSzdCBmoAU+Vq

Usage:

Configuration is fully documented here. In order to customize program behavior use "export" command to the directory of your choice and then supply path to your configuration file during program run.

Program has detailed logging configured by default (by default conversion.log in current working directory) - in case of problems, take a look there first.

>>> ./fb2c

NAME:
   fb2converter - fb2 conversion engine

USAGE:
   fb2c [global options] command [command options] [arguments...]

VERSION:
   "program version" ("go runtime version") : "git sha string"

COMMANDS:
   convert     Converts FB2 file(s) to specified format
   synccovers  Extracts thumbnails from documents (Kindle only!)
   dumpconfig  Dumps active configuration (JSON)
   export      Exports built-in resources for customization
   help, h     Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --config FILE, -c FILE  load configuration from FILE (YAML, TOML or JSON). if FILE is "-" JSON will be expected from STDIN  (accepts multiple inputs)
   --debug, -d             prepare archive with details of a current run (may overwrite some log settings) (default: false)
   --help, -h              show help (default: false)
   --version, -v           print the version (default: false)

Additional help for any command could be obtained by running ./fb2c help COMMAND-NAME.

Examples:

In order to convert all fb2 files in c:\books\to-read directory and get results in d:\out directory without keeping original subdirectory structure sending files to Kindle via e-mail in process execute

fb2c.exe convert --nodirs --stk --to epub c:\books\to-read d:\out

If you want resulting mobi files to be located alongside with original files, do something like

fb2c.exe convert --to mobi c:\books\to-read c:\books\to-read

MyHomeLib support:

Windows builds come with full MyHomeLib support. Just make sure that your MyHomeLib\converters directory does not contain old fb2mobi and/or fb2epub subdirectories and unpack Windows distribution file for your archtecture there. It is a drop-in replacement and should be functional out of the box in most cases.

NOTE:

fb2mobi.exe looks for fb2mobi.toml in its directory (similarly fb2epub.exe looks for fb2epub.toml), so any additional customization is easy.
Do not install MyHomeLib in either %ProgramFiles% or %ProgramFiles(x86)% directory - it is bad idea. Since for regular user accounts In Windows those places are write-protected you will have difficulties copying converters there and converters will have problems creating conversion logs which are enabled by default.

BREAKING CHANGES:

Starting with version 1.62.0 "Send to Kindle" functionality supported for EPUB files only. This reflects current Amazon intention to completely drop MOBI support on backend. As the result converter drops "transfer" subcommand, disables sending of MOBI files via e-mail and moves support for this from fb2mobi to fb2epub.
Starting with version 1.64.0 --debug flag produces zip archive with artifacts for debugging either in directory of the converter or if it is inaccessible in temporary directory. Environment variable FB2C_DEBUG set to "Yes" could be used with fb2epub.exe and fb2mobi.exe for similar effect. Resulting archive could be shared to facilitate troubleshooting.

rupor-github / fb2converter