#! /bin/bash

basedir=/root/Verzeichnis/

for i in `ls $basedir`
do
  echo "Directory: $i"
        for j in `ls $basedir$i/*.ext`
        do
            echo "Full file name: $j"
            fl = <Hier soll nur der Dateiname rauskommen>
            echo "File: $fl"
            echo "New name: /root/NeuesVerzeichnis/${i}_${fl}.ext"
        done
done