#!/usr/bin/env zsh
set -e
autoload regexp-replace
typeset -A seen
while read url ; do
    url="$url " # to be sure that next line will work
    url=${${=url}[1]}
    dir=${url:gs#/#_#}
    regexp-replace dir "^.*__" ""
    regexp-replace dir "_$" "" || :
    dir=feeds/$dir
    seen[$dir]=1
    [[ -e $dir ]] && continue || :
    mkdir -p $dir/{cur,new,tmp} # make it maildir
    echo "$url" > $dir/url
done
for dir (feeds/*) [[ $seen[$dir] -eq 1 ]] || print disappeared: $dir