#!/bin/bash
s='52.200.238.131 - - [31/Jan/2017:10:30:21 +0000] "POST /v1/articles?key=sEahu58asdasd'
echo $s | sed -E 's#.*(\[[0-9]{2}/[A-Za-z0-9]{3}/[0-9]{4}).*(key=[A-Za-z0-9]+).*#\2 \1#'
IyEvYmluL2Jhc2gKcz0nNTIuMjAwLjIzOC4xMzEgLSAtIFszMS9KYW4vMjAxNzoxMDozMDoyMSArMDAwMF0gIlBPU1QgL3YxL2FydGljbGVzP2tleT1zRWFodTU4YXNkYXNkJwplY2hvICRzIHwgc2VkIC1FICdzIy4qKFxbWzAtOV17Mn0vW0EtWmEtejAtOV17M30vWzAtOV17NH0pLiooa2V5PVtBLVphLXowLTldKykuKiNcMiBcMSMn