save config diffs

bin/create_config.sh

@@ -129,7 +129,7 @@ fi
 
 # --- create target file
 diff "${tmpfile}" "${outfile}" >> ${cfgdiff} 2>/dev/null
-if [ $? -eq 0 && -f "${outfile}" ]; then
+if [ $? -eq 0 -a -f "${outfile}" ]; then
     _warn "INFO: no changes."
 else
     mv -f "${tmpfile}" "${outfile}" || exit 4