#!/bin/bash s='1.2.3.4 127.0.0.1 192.168.1.0/24 1111:2222:3333:4444:: 5.6.7.8' sed -En '/([0-9]+\.){3}[0-9]+/{s,,/ip add address=&,p}' <<< "$s"
Standard input is empty
/ip add address=1.2.3.4 /ip add address=127.0.0.1 /ip add address=192.168.1.0/24 /ip add address=5.6.7.8