mount_stuff_into_chroot

#!/bin/bash

help() {
   echo 'usage: mount_stuff_into_chroot [--umount] path_to_chroot'
   echo '       mount_stuff_into_chroot --help'
   echo
   echo '    Mounts /proc /sys and /dev into chroot'
   echo '    and makes sure /tmp is correctly set up.'
   echo
   echo '    With --umount: umounts all those filesystems'
   echo '    again, that were previously mounted into'
   echo '    the chroot.'
   echo
   exit 1
}

[ "$1" == "--help" ] && help

if [ "$1" == "--umount" ]; then
  MOUNT_OR_UMOUNT=umount
  shift
else
  MOUNT_OR_UMOUNT=mount
fi

if [ "$1" == "" ]; then
  echo "ABORTING: chroot path not given" >&2
  exit 1
else
  CHROOT="$1"
fi

set -e          # stop on error
set -u          # stop on undefined variable
set -o pipefail # stop part of pipeline failing

if [ "$MOUNT_OR_UMOUNT" == "mount" ]; then
  for fs in proc sys dev tmp; do
    if [ ! -d "${CHROOT}/${fs}/" ]; then
      sudo mkdir "${CHROOT}/${fs}/"
    fi
  done

  sudo mount -t proc  /proc "${CHROOT}/proc/"
  sudo mount -t sysfs /sys  "${CHROOT}/sys/"
  sudo mount --bind   /dev  "${CHROOT}/dev/"

  # /tmp
  chmod ugo+rwx "${CHROOT}/tmp/"
  chmod +t      "${CHROOT}/tmp/"
else 
  sudo umount -l "${CHROOT}/dev/"
  sudo umount "${CHROOT}/sys/"
  sudo umount "${CHROOT}/proc/"
fi