shar prefix for deb installation

#!/bin/sh
if [ "$(id -u)" != "0" ]; then
    echo "ERROR: Must be run as root"
    exit 1
fi
if [ "$1" != "xxx" ]; then
    D=$(readlink -f $0)
    X=$(mktemp -d)
    cd $X
    sh $D xxx
    dpkg -i *.deb
    rm -rv $X
    exit 0
fi