alpine-chroot

 1#!/bin/sh
 2# umount all mountpoints of an existing alpine chroot.
 3
 4set -e
 5
 6if [ $# -lt 1 ]; then
 7	echo "USAGE: ${0##*/} CHROOT..." 1>&2
 8	exit 1
 9fi
10
11if [ $(id -u) -ne 0 ]; then
12	echo "${0##*/} has to be started as root." 1>&2
13	exit 1
14fi
15
16for chroot in $@; do
17	for mountpoint in /dev /sys /run /proc; do
18		busybox mountpoint -q "${chroot}/${mountpoint}" && \
19			umount -l "${chroot}/${mountpoint}"
20	done
21
22	for mountpoint in $(mount | cut -d " " -f3 | grep "^${chroot}"); do
23		umount -l "${mountpoint}"
24	done
25done