Something

#!/bin/bash

set -e
set -x
METHOD=rsync
HOST=mirror.xxx.com
REPOPATH="ftp/mirror/ubuntu"
DIST=gutsy
REPOS="main/debian-installer main/installer-i386 main restricted"
ARCHS="i386"
WORKDIR="."

if test ! -d ftp;then
  mkdir ftp
fi

for REPO in $REPOS;do
  for ARCH in "$ARCHS";do
    REPOFILE=`echo "$REPO" | sed -e 's/\//-/g'`
    if test $METHOD = "rsync";then
      rsync rsync://$HOST/$REPOPATH/dists/$DIST/$REPO/binary-$ARCH/Packages.gz /tmp/repo.$REPOFILE.$ARCH.gz && echo ""
      if test -f "/tmp/repo.$REPOFILE.$ARCH.gz";then
        echo "dists/$DIST/$REPO/binary-$ARCH/Packages.gz" > /tmp/list.$REPOFILE.$ARCH.txt
        gunzip -c /tmp/repo.$REPOFILE.$ARCH.gz |grep ^Filename:|sed -e "s/Filename: //" >> /tmp/list.$REPOFILE.$ARCH.txt
      else
        if test "$REPOFILE" = "main-installer-i386";then
          echo "dists/$DIST/$REPO" > /tmp/list.$REPOFILE.$ARCH.txt
        fi
      fi
      rsync --recursive --links --hard-links --times --verbose --stats  --files-from=/tmp/list.$REPOFILE.$ARCH.txt rsync://$HOST/$REPOPATH ftp
    fi
  done
done