#!/bin/bash
s='<a href="url with spaces">description with spaces</a>'
sed -Ee 's`.*href="(.*)">(.*)</a>.*`"\1","\2"`' <<< "$s"
awk -F'href="|">|</a>' '{gsub(/ /, "%20",$2);print "\""$2"\",\""$3"\""}' <<< "$s"