I have about 200 .djvu ebooks which I want to convert into .pdf. Since one-by-one conversion is tiresome I want to know if there is a way to convert them all at once. Any help will be appreciated.
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possible duplicate of Converting DJVU to PDF – qbi Feb 28 '13 at 10:18
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1@qbi Where does it tell how to convert multiple djvu files? – mikewhatever Feb 28 '13 at 12:49
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my question is about BULK conversion! – kernel_panic Feb 28 '13 at 14:23
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@mikewhatever, This is basically combination of two questions: http://askubuntu.com/q/46233/58990 and a variation of question like http://askubuntu.com/q/35922/58990. Also the first question already includes a lot of information, which would be replicated here. – ignite Feb 28 '13 at 15:10
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You could use ddjvu, in a shell script. That said, the output PDFs are much larger (x10), which makes it hardly worth the effort. Ubuntu has no problem reading djvu files, but if your reason is good enough, use the following script.
Warning: Do not try it on 200 files right away. Run a test first on one or two small ones, to get the feel of how long it takes, and to make sure you are satisfied with the result. Press Ctrl + C, in case you want to stop the process.
#!/bin/bash
for i in *.djvu;
do ddjvu -format=pdf -scale=100 "$i" "${i/%.djvu/}.pdf"
done
...or the same, as a one-liner
for i in *.djvu; do ddjvu -format=pdf -scale=100 "$i" "${i/%.djvu/}.pdf";done
Simply run that in a folder with djvu files. The -scale=100 option downscales the output images, which makes the process much faster, and the output files' size more reasonable. Without it, the resulting PDFs were much larger then the originals, and took ages to convert, at least in my tests.
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mikewhatever
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1With
-scale=100I get a blurred pdf. Without it I get a sharp pdf. – Alessandro Jacopson Jan 04 '14 at 12:19 -
Whatever works for you. If the process is slow, you could try adjusting the scale value relative to your display's DPI. There are other options as well: http://linux.die.net/man/1/ddjvu – mikewhatever Jan 04 '14 at 12:29
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For an approach that preserves the text layer see here. For batch operation you could use the above one-liner approach or GNU Parallel. – Stefan Schmidt Aug 31 '23 at 11:53
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Personally I really like Calibre, which is a great for managing, converting, synching, sharing and editing ebooks. You can do batch conversions with it and djvu to PDF is supported. To install, just enter the following via cli:
sudo apt-get install calibre
You can find info on the software at http://calibre-ebook.com/about
I hope it helps. :)
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