#!/bin/sh -e standalone_usr() { local device_root=$(stat --printf='%d\n' /) local device_usr=$(stat --printf='%d\n' /usr) if [ "$device_root" != "$device_usr" ]; then return 0 fi return 1 } booted_with_initramfs() { # created by update-initramfs if [ -d /run/initramfs/ ]; then return 1 fi return 0 } has_initramfs() { standalone_usr || return 0 booted_with_initramfs || return 0 echo "/usr is a standalone filesystem, this requires using an initramfs." exit 1 } case "$1" in install) # check the prerequisites on the first install if [ -z "$2" ]; then has_initramfs fi ;; esac