Compare 2 calibre libraries

[Erromanski]

My friend and I both have a large calibre library. Probably with a lot of books the same, but also books that we don't have both. We could have the same books with different formatted titles, authors etc. How can we compare our libraries to find unique books?

[brewjono]

I have wanted to do this same thing myself so am keen to hear if there are any suggestions.

[kovidgoyal]

Take the metadata.db files from the two libraries and sue them to create two empty libraries with no actual book files. Then use copy to library in calibre to merge the two. Then use the duplicate finder plugin to check for duplicates in the merged libraries.

Or output the list of books as an XML or CSV catalog and use any tool you like to compare it like a spreadsheet program or a diff tool.

[eltrkbrd]

After recently experimenting with calibre portable and figuring out how to merge libraries & remove duplicates, I've decided to share my experience with other calibre neophytes out there in hopes that it may simplify things a bit...

The calibre "convert books" | "create a catalog" | export to CSV (w/ title field only) option works nice just for a simple book list comparison. For this task I used Notepad++ (Windows) with the built in "compare" plugin along with the TextFX plugin to sort lines (unique).

Another option as Kovid suggested is to simply copy the calibre metadata.db file for each existing library without the books into separate directories, then merge and compare with Kiwidude's "Find Duplicates" plugin.

I found it easier to first click calibre "Add books" | then "control the adding of books" | select the "automerge added books" and choose "ignore duplicate" from the drop down list options & finally select the "check for duplicates" under "automatic adding" tab on that same window.

After changing the above options in calibre, click the library (books) icon in the toolbar and select "switch/create library" | "use the previously existing library (default option)" | browse to the folder you saved the metadata.db file to; say library1 for example | then click ok to open library1 in calibre. Then browse again to the folder you saved the metadata.db file for say library2 in and click ok to open that in calibre.

Note that you can now easily switch libraries using the "quick switch" option by clicking the small black down arrow icon to the right of the library icon in calibre.

Once you are in say library #2, select all ebooks (ctrl + a) | then right click and select the option "copy to library" library1. Now quick switch to library1 and you will notice all the book entries from library2 will have been merged with libary1 and the duplicates ignored.

Some other tips I picked up searching the forums here is to use the "Duplicate Finder" plugin's "binary compare" feature to remove binary identical books. Then search for “formats:false” to delete empty book entries from calibre without any ebook formats (book entries withouth any pdf,epub,mobi files, etc.). Alternatively, you can add the "formats" custom column in calibre and sort by that column to delete the empty book entries from calibre (binary compare doesn't automatically delete the book entries from calibre because of metadata that you may want to retain/merge).

For more tips on using Duplicate Finder, see:
https://www.mobileread.com/forums/sho...d.php?t=131017
http://blog.calibre-ebook.com/2011/1...te-finder.html

Lastly, my personal thanks to Kovid Goyal and the many others in the calibre community for making this open source project such an inspiration...

Enjoy!

[Richs]

Great post!!! thanks for simplifying that.

[joalmoju]

I use the connect to option, it let you use a folder (for example an USB storage with a calibre library). It let me compare which books are in both libraries and copy them.

[Tanjamuse]

What about overwriting if you have updated the metadata in one library? Or keeping the newest?

[allowingtoo]

Originally Posted by eltrkbrd

After recently experimenting with calibre portable and figuring out how to merge libraries & remove duplicates, I've decided to share my experience with other calibre neophytes out there in hopes that it may simplify things a bit...

I found it easier to first click calibre "Add books" | then "control the adding of books" | select the "automerge added books" and choose "ignore duplicate" from the drop down list options & finally select the "check for duplicates" under "automatic adding" tab on that same window.

Lastly, my personal thanks to Kovid Goyal and the many others in the calibre community for making this open source project such an inspiration...

Enjoy!

I know this is a VERY old post but FINALLY!! Something that worked for me. I tried the old tried and true way via the Calibre manual importing my books from my old computer to my new computer and ended up with some errors for some reason and all my books did not get imported. So I kept searching and ran across this and it worked.