Lowercase all file names in git repository

lowercase_filenames.sh

#!/bin/sh
# Lowercase all file names in git repository
# SPDX-License-Identifier: 0BSD

# FIXME: recurse subdirectories
for file in *; do
  lowercase_name=$(echo $file | awk '{ print tolower($0) }')

  # https://stackoverflow.com/a/30654833/8507637
  git mv "${file}" "_${lowercase_name}"
  git mv "_${lowercase_name}" "${lowercase_name}"
done