man apt-clone

[adric]

APT-CLONE(8)                                                     APT-CLONE(8)

NAME
       apt-clone  -  ZFS  integrated APT package handling utility -- command-
       line interface

SYNOPSIS
       apt-clone [-hltsyv] [-a=clone-name] [-r=clone-name]
                 [-b=bootmenu-count] [-k=clone-count] [-x=http-proxy]
                 apt-cmd pkg1 pkg2...

DESCRIPTION
       apt-clone is the command-line tool for handling packages, and  may  be
       considered  the  user's "front-end" to the apt-get(8). It manages GRUB
       menu and ZFS 'syspool' filesystems. Two upgrade methods supported:  1)
       safe  upgrades via cloning a currently active filesystem and later ch-
       rooting into it to  perform  actual  upgrade  operation;  2)  in-place
       (live)  upgrades  by checkpointing a currently active filesystem prior
       to any upgrade modifications done by apt-get utility. The live upgrad-
       ing,  as the name implies, happens in-place on the running system, and
       without reboot. Unless the safe -s option is explicitly specified, the
       system  will automatically detect whether the upgrade will require re-
       boot, and if so, it will clone the active filesystem and  safely  per-
       form  the  software upgrade within this ZFS clone. A user then has two
       options: reboot into the new  (upgraded)  system  folder  or  continue
       working  (and possibly activate the upgrade and reboot into it later)...

Full man page at http://www.nexenta.org/os/AptCloneMan