while ! ip link show up | egrep -q "^[0-9]+: +$tapname:"; do
echo "Waiting for $tapname to come UP...$(($expire - $(date +%s)))s left" >&2
while ! ip link show up | egrep -q "^[0-9]+: +$tapname:"; do
echo "Waiting for $tapname to come UP...$(($expire - $(date +%s)))s left" >&2