Modify directory contents based on a collection of existing files http://hitherejoe.com/wordpress/using-bash-modify-directory-contents-based-existing-files/

DirectoryContents

#! /bin/bash
path="./current/";
assets="./assets/";
 
files=( "$path"* )
files=( "${files[@]##*/}" )
 
for dir in $assets*; do
	for file in "$dir"/*; do
		filename="${file##*/}"
		if ! [[ ${files[*]} =~ "$filename" ]]; then
  			rm $file
		fi
	done
done