# The procedures to add multiarch i386 in Debian Jessie
# Add (For example, i386)

# dpkg --add-architecture i386
# apt-get update

Comment: Nothing is really changed until you do the above command to update the available package lists


dpkg --get-selections | grep ":i386" | awk '{print $1}'


Before you remove the selected architecture, please remove/purge all the package in this architecture:

apt-get purge `dpkg --get-selections | grep ":i386" | awk '{print $1}'

Remove (For example, i386)

dpkg --remove-architecture i386