shell functions for bilibop scripts

 Bilibop helps to maintain a Debian GNU/Linux operating system installed
 on an external media (USB, FireWire, Flash memory, eSATA). It hardens
 standard rules and policies to make the system more robust in this
 particular situation.
 .
 This package provides shell functions usable by other bilibop scripts on the
 running system or into the initramfs environment. These functions use /dev,
 /proc and /sys databases to output the drive name or the partition hosting
 the running system, and are fully usable by any unprivileged user or
 application. Dm-crypt, LVM, loop devices, aufs and overlay root filesystems
 (and almost any combination of them) are supported. A 'drivemap' command is
 also provided, to show block devices in a tree of dependencies.