MacOS – Request Applescript to copy only one file type from 2 folders, into a 3rd folder

If the .mobi and .azw files are directly under the .sdr folders, try running a command like this in Terminal:

cd /containing/folder;for d in *.sdr;do ls "$d"|grep -Eq '\.(mobi|awz)$'||echo rm -r "$d";done

Remove echo to actually delete the folders.

This is rather easy combining some standard tools:

• file for looking up the mime type
• tr to remove the slashes (otherwise, you'd have nested folders for different file groups)
• well, some obvious mkdir and mv commands

for file in *
do
    mime=$(file --brief --mime-type "$file" | tr '/' '_')
    mkdir -p "$mime"
    mv "$file" "$mime/$file"
done

Alternatively, you could also directly list file extensions for each expected mime type and automatically rename them appropriately.

for file in *
do
    mime=$(file --brief --mime-type "$file")

    case "$mime" in
    "image/jpeg")
        extension="jpeg"
        ;;
    "text/plain")
        extension="txt"
        ;;
    "application/pdf")
        extension="pdf"
        ;;
    *)
        continue;
        ;;
    esac

    filename="${file%.*}"

    mv "$file" "$filename.$extension"
done

Be aware, that for sake of readability I did not take care of file names containing spaces. If you have them, you'll have to apply one of the patterns to deal with spaces in file names. As it rather seems you're not having them I left them out, as they make the scripts looking much more complicated as they are.