Merge pull request #2069 from pi-hole/fix/nullbyte

Fix error: /opt/pihole/gravity.sh: 385: Warning: command substitution: ignored null byte in input

gravity.sh

@@ -387,9 +387,8 @@ gravity_ConsolidateDownloadedBlocklists() {
     if [[ -r "${i}" ]]; then
       # Remove windows CRs from file, convert list to lower case, and append into $matterAndLight
       tr -d '\r' < "${i}" | tr '[:upper:]' '[:lower:]' >> "${piholeDir}/${matterAndLight}"
-
       # Ensure that the first line of a new list is on a new line
-      lastLine=$(tail -1 "${piholeDir}/${matterAndLight}")
+      IFS= read -r -d '' lastLine <"${piholeDir}/${matterAndLight}" || [[ $lastLine ]]
       if [[ "${#lastLine}" -gt 0 ]]; then
         echo "" >> "${piholeDir}/${matterAndLight}"
       fi