#!/bin/bash

ftp_dir="path/to/catalog"
archive_dir="$ftp_dir/archive"
datetime=$(date +%d.%m.%Y)
remove_days="30"

if [[ $(find $ftp_dir -maxdepth 1 -type f | wc -l) == 0 ]]; then
 exit 0
else
  mkdir $archive_dir/$datetime
  find $ftp_dir -maxdepth 1 -type f -print0 | xargs -0 -I {} mv {} $archive_dir/$datetime
  chown -R www-data: $archive_dir/$datetime
fi

find $archive_dir  -mtime +$remove_days -delete