Ok, I solved that with this script:
#!/usr/bin/env bash
electrum daemon -d -D .
for file in *;
do
echo Using wallet: $file
electrum load_wallet -w "./$file" -D . --password xyz
if [[ $? -ne 0 ]]; then
#echo ERROR
continue
fi
electrum unlock -w "./$file" -D . --password xyz
electrum listaddresses -w "./$file" -D . | electrum getprivatekeys - -D . -w "./$file" | jq -r ".[]"
electrum close_wallet -w "./$file" -D .
done 2> /dev/null
electrum stop