Makes folders for each epub in the current directory, based on title and author tags.

make-epub-folders.sh

#!/bin/bash

#Requires exiftool installed

#Subfolder to store results in
containingfolder="./epubs-folder/"

for i in *.epub; do
    [ -f "$i" ] || break

    title=$(exiftool -T -Title "$i")
    author=$(exiftool -T -Creator "$i")
    dirname=${title// /_}"-"${author// /_}
    
    mkdir -p ${containingfolder}${dirname}
    
    mv "$i" "${containingfolder}${dirname}"
    
    echo $dirname
done

#Outputs any folders with multiple files
find ${containingfolder} -type f -iname '*.epub' -printf '%h\n'|sort|uniq -cd