#!/bin/sh

COLS="name,type,size,mountpoint"

drives=$(lsblk -rpo "$COLS" | awk '$2=="part"&&$4!~/boot|home|SWAP/&&length($4)>1{printf "%s (%s) on %s\n",$1,$3,$4}')
[ -z "$drives" ] && exit
chosen=$(echo "$drives" | dmenu -i -p "Which drive?" | awk '{print $1}')
[ -z "$chosen" ] && exit
sudo -A umount "$chosen" && notify-send "$chosen unmounted"