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Calibre helper scripts (ISBN guessing, RTF to DOC conversion,hanging books detection, ...).

Project description

This is a set of standalone scripts which I wrote to help managing my Calibre ebook-library.

Script list

The following scripts are available:


Checks books without ISBN (set in metadata) for ISBN-like string present in leading pages. If found, add it to the metadata (what makes it possible to download full metadata, covers, etc).


Convert any .doc to .rtf (unless already present) - using openoffice.


Checks given directory tree for books not yet present in calibre, add them if found. Uses binary file comparison to check whether the file is identical (file name and metadata are not used, on purpose).


Checks whether Calibre database directory contains some unregistered files and report them if found.


Report duplicates, adding information of which of them are surely safe to merge (because duplicated books are identical or because formats do not overlap), and which require careful examination (because different files in the same format exist).

Script details


Queries Calibre for all books without ISBN, then tries to locate ISBN inside (via scanning a few leading pages) and updates Calibre book metadata if ISBN is found.

Run it without parameters:


Any ISBN numbers found will be added to the book metadata (and the script will report them). Books are scanned from the newest, so you can abort (Ctrl-C) script once it handled new books.

Later on ISBN can be used to grab the book metatada and/or book cover inside Calibre GUI. Just spawn Calibre and look for books with ISBN set and missing metadata, for example using query like:

isbn:~[0-9] not publisher:~[a-z]

(above means: isbn contains some digit, publisher does not contain any letter). Depending on your workflow, you can then either

  • grab metadata automaticaly (mark all those books, right click, pick Edit Metadata Information/Download Metadata)
  • review each book individually (mark those books, right click, pick Edit Metadata Information/Edit Metadata Individually, then click Fetch Metadata on every book successively and review whether it fits).


Queries Calibre for all books which have only .doc format, then uses OpenOffice to convert them to .rtf and add this format as an alternative.

OpenOffice (and pyuno libraries provided by it) are used in the process.

Run it without parameters:


Note: from time to time the script happens to crash on the end of the job (while finishing). I haven’t diagnosed the reasons (most likely the problem is in the libraries I use), but the crash is harmless and does not influence the actual conversion process.


Reports the files present inside Calibre library directory but not present in the database (and therefore not visible in the Calibre interface).

The files are reported to standard output. To add them all to calibre, pipe output. For example:

calibre_find_books_missing_in_database | xargs -d "\n" calibredb add

(but, better, review everything beforehand)


The problematic scenario may happen for example if Calibre is used from two or more machines over synchronized or networked directory and, by mistake, two copies are run simultaneously. Or in case of some crashes.


Scans given directory and/or specified files, adds to calibre all books which are not yet present there.

Duplicate checking is done solely according to the file content. The file is skipped if identical file is already present in Calibre.

I initially wrote this script to handle I want to ensure everything is already imported and can be deleted scenario, but over years I tend to use it for most batch ebook imports.


calibre_add_if_missing /home/jan/OldBooks

(import any books below OldBooks which are not yet present, don’t touch this directory - which probably can be removed afterwards).

Or maybe:

calibre_add_if_missing --tag="programming,web-development" \
    --move=$HOME/ebooks-done  ./freshly-bought/*.epub

(add all .epub files from ./freshly-bought, tag them with programming and web-development, move all succesfully imported files to ~/ebooks-done/).

For all options, run:

calibre_add_if_missing --help


Analyzes calibre database looking for likely duplicates, and reports them, adding info of which of those are surely identical, and which require examination.

Do not perform any changes, just prints report (as text, or html, or javascript-enabled html from which reviewed items can be removed by clicking).


calibre_report_duplicates -f txt

(text output to the console):

calibre_report_duplicates -f html -o /tmp/report.html

(HTML output redirected to file):

calibre_report_duplicates -f js -o /tmp/report.html

(also HTML, but with buttons to hide rows, handy for review).

See also:

calibre_report_duplicates --help

Installation and configuration


Calibre must be installed, properly configured and has some database (otherwise it does not make sense to run those scripts). The:


command must be in PATH (or calibredb variable inside .ini file must be properly set, see below).

Tools providing commands:


should be installed and present in PATH (or properly configured in .ini, or disabled in .ini, see below). On Ubuntu Linux or Debian Linux those can be installed from standard repositories, just install the following packages:


Python 2.6 or 2.7 is required (scripts are using some features introduced in 2.6 - in particular tempfile extensions, subprocess and namedtuple). Also, lxml library must be installed. On Debian or Ubuntu just install the following packages:


For calibre_convert_docs_to_rtf to work, ootools library must be installed. Simplest method to install it:

easy_install ootools

(on Ubuntu sudo easy_install ootools).

I develop and use those scripts on Ubuntu Linux. They should work on Windows or Mac if necessary tools are installed, but I’ve never tried it.

Actual installation


sudo pip install mekk.calibre


pip install --user mekk.calibre

should do (the latter requires adding ~/.local/bin to PATH). In case you don’t want to mess with your system or user directories, consider using virtualenv.


The ~/.calibre-utils file can be used to configure some program settings. The file is created, if missing, whenever any of the scripts is run, and can be customized.

Here is the default content:

catdoc = catdoc
archmage = archmage
djvutxt = djvutxt
calibredb = calibredb
pdftotext = pdftotext

guess_lead_lines = 10000
guess_lead_pages = 10

The commands section defines location of the external tools being used. In case the commands are present in PATH, bare names can be used. Otherwise full path can be specified. Finally, if some tool is missing, it can be defined as empty string.

The isbn-search section specifies how many leading pages (in page-based document formats like PDF or DJVU) or lines (in the free formats like TXT or CHM) are scanned looking for ISBN-like strings.

For example, the file can be changed so:

catdoc = /usr/local/bin/catdoc
archmage =
djvutxt =
calibredb = /opt/calibre/calibredb
pdftotext = pdftotext

guess_lead_lines = 12000
guess_lead_pages = 15

In such a case catdoc will be used from /usr/local/bin, calibredb will be expected in /opt/calibre, pdftotext will be sought in PATH, and archmage and djvutxt will be treat as missing (so the isbn guessing script won’t be able to scan CHM and DJVU files for ISBN and will ignore them).


(only major changes described)


calibre_add_if_missing: added --force-language (to set book language attribute).

calibre_add_if_missing crashed in case it was to move the file out (--move option was used), but identically named file already existed in the target directory. After the fix, file is moved to some subdirectory of target instead.


calibre_report_duplicates enhancements:

  • output format is chosen by --format=txt or --format=html (instead of --html)
  • added javascript-enabled output (--format=js) which supports clicking-out report items
  • using SimHash instead of difflib to look for similar titles. MUCH faster, provides a bit different but sensible results
  • reporting similar authors
  • new option --cache (use cached manifest to speed up reruns on large libraries)
  • new option --output (name output file)


Fixed errors:

  • calibre_guess_and_add_isbn crashed with Unicode decode error while saving isbn to book with non-ascii character in title (wrong diagnostic print),
  • as since calibre 1.0 calibredb catalog --sort-by=id crashes (and, therefore scripts internally using this command crash too), we use sort by timestamp instead.


calibre_add_if_missing fixes:

  • even runs executed without --cache preserve cached metadata for possible next run,
  • runs with --cache ignore cached data if they are more than 24 hours old,
  • in case file found in calibre catalog does not exist (what can happen if it was renamed or deleted while we run, or if cache is in use and some books were removed since it was created), calibre_add_if_missing just warns, but continues it’s work (instead of exiting with an error).


Python3 compatibility work, scripts should be runnable under Python3 (note: daily I still use them under 2.7, so 3 is less tested).

calibre_add_if_missing performs some comparison of epub internals in case possible duplicate of similar size exists. In particular, it is able to ignore calibre_bookmarks (so duplicate epub is not added due to this file being added or modified by viewer).

calibre_add_if_missing has --cache option (reuse cached catalog from previous run to speed up processing on large libraries).

calibre_add_if_missing has --dry-run option.


calibre_add_if_missing has --move option (move succesfully added files to another directory - likely something trash-like).

calibre_add_if_missing has --title-from-name option (force using filename as title instead of processing metadata).

calibre_add_if_missing has --tag and --author options (force given tags and/or author instead of processing metadata).

calibre_add_if_missing copies filename as title for .doc, .docx, .rtf and .txt files. Those extremely rarely have sensible metadata.


calibre_find_books_missing_in_database no longer reports book subdirectories and such (reasoning: I use book subfolders to store things like source code added to the book or book sources, at the same time it is not the place where calibre would put the book by itself).

Fixed two more “UnicodeEncodeError” bugs (reported for books without files and with unicode character in names)


calibre_guess_and_add_isbn catches various errors, reports them, and continues to work. For any errors information mentions problematic book name.

Ctrl-C aborts ISBN guessing and properly cleans up.

#5 - fix for ISBN’s containing X letter.


calibre_add_if_missing disables Calibre own duplicate checking (which is title based, so too simplistic, and occasionally rejects fine books) and prints detailed info about found actual duplicates (if present).

Some calibre_report_duplicates improvements:

  • pruning some redundant matches (if a is similar to b, a is similar to c, and b is similar to c, we don’t report the latter),
  • books which have same/similar author and title are not reported as duplicates if they have the same series and different series index (so different volumes of the same book are no longer reported as possible duplicates).

calibre_guess_and_add_isbn fixes:

  • #3 - avoiding crash on latin-1 encoded chm files (during ISBN detection)
  • handling some Unicode charactes in ISBN text (hard space, long dash, …)
  • verifying ISBN checksum before using it.


Added calibre_report_duplicates.

calibre_add_if_missing can be given individual files (initially only complete directories could be processed).


First serious release. Working calibre_find_books_missing_in_database, calibre_guess_and_add_isbn, calibre_convert_docs_to_rtf, calibre_add_if_missing.

Project details

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