#!/bin/bash set -e format_offset () { i=$1 if ((i == 0)) then echo "" elif ((i > 0)) then echo "+$i" else echo "$i" fi } $NFT add table t for offset in -11 -10 0 10 11 do $NFT add flowtable t f "{ hook ingress priority filter `format_offset $offset`; devices = { lo }; }" $NFT delete flowtable t f done