sanitize file names, or sanitize recursively

sanitize.sh

#!/usr/bin/env bash

sanitize_node() {
	shopt -s extglob

	filename=$(basename "$1")
	directory=$(dirname "$1")
	if [ -f "$1" ]; then
		extension=".${filename##*.}"
	else
		extension=""
	fi
	name="${filename%.*}"
	cleanname="${name//+([^[:alnum:]_-\.])/_}"
	if (test "$filename" != "${cleanname}${extension}"); then
		finalname="${cleanname}${extension}"
		if [ -e "${cleanname}${extension}" ]; then
			num=1
			while [ -e "${cleanname}-${num}${extension}" ]; do
				((num += 1))
			done
			finalname="${cleanname}-${num}${extension}"
		fi
		mv "$1" "$directory/$finalname"
	fi
}

usage() {
	echo "sanitize file names"
	echo "usage:"
	echo "- sanitize [file]"
	echo "- sanitize -R [directory]"
}

[[ "$1" == "-R" && -d "$2" ]] || [[ -f "$1" && "$2" == "" ]] || { usage && exit 1; }

if [ "$1" == -R ]; then

	export -f sanitize_node
	find "$2" -depth -exec bash -c 'sanitize_node "{}"' \;

else

	sanitize_node "$1"

fi

modified from https://odoepner.wordpress.com/2011/10/13/bash-script-to-recursively-sanitize-folder-and-file-names/