sudo aptitude purge `dpkg --get-selections | grep ":i386" | awk '{print $1}'`
# or
sudo apt-get purge ".*:i386"
sudo dpkg --remove-architecture i386
==== add i386 architecture ====
dpkg --add-architecture i386
apt-get update
apt-get install gpm tcpdump bmon tinc ppp pptpd mc links2 gparted hdparm smartmontools smart-notifier valgrind openssh-server
apt-get install wireshark mtr