added utc-to-local.sh

#!/bin/bash

# Usage: input: 2018-03-19T17:42:23.000Z

input=$1

tmpstr=$(echo $input | grep -oE "\d+-\d+-\d+T\d+:\d+.\d+.000Z")

if [ ! -z "$tmpstr" ]; then

  dstring=${tmpstr/.000Z/ +0000}

  local_time=$(date -jf "%Y-%m-%dT%H:%M:%S %z" "$dstring" "+%Y-%m-%d %H:%M.%S")

  echo $local_time

else

  echo Unsupported $input: Please convert to yyyy-mm-ddTHH:MM:ss.000Z format.

fi