#!/bin/sh

# can use ls pipe to sed pipe to bash, similar to eval? see comment at link:
# link also show perl-rename approach
# https://linuxconfig.org/rename-all-files-from-uppercase-to-lowercase-characters
# if only change ' ' to '_' `rename` might be sufficient, for upper to lower case might need perl-rename if want concise

# ./_filename will be renamed ./filename, not what I want, need improve
# -exec can't replace -execdir here, can write a -exec version

find "$@" -depth -execdir sh -c 'dest="$(echo "$1" | tr -d "\047" | sed -E -e "s/([[:lower:]])([[:upper:]])/\1_\2/g" | tr "[:upper:] " "[:lower:]_" | tr -s "[:punct:]" | sed -E -e "s#/-#/#g" -e "s/_([[:punct:]])/\1/g" -e "s/([[:punct:]])_/\1/g" | tr -s "[:punct:]")"; [ -e "$dest" ] || mv -v -- "$1" "$dest"' shell '{}' \;