bash: clean filenames

clean_file_names.sh

#!/bin/bash
find . -depth -type f -exec bash -c '
for f; do
  dir=$(dirname "$f")
  name=$(basename "$f")

  ext="${name##*.}"
  base="${name%.*}"

  clean=$(echo "$base" | tr -cd "A-Za-z0-9\ \-_")

  # fallback if name becomes empty
  [ -z "$clean" ] && clean="file"

  target="$dir/$clean.$ext"

  mv -- "$f" "$target"
done
' bash {} +