/usr/bin/uck-remaster-unpack-iso is in uck 2.4.7-0ubuntu2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92  | #!/bin/bash
###################################################################################
# UCK - Ubuntu Customization Kit                                                  #
# Copyright (C) 2006-2010 UCK Team                                                #
#                                                                                 #
# UCK is free software: you can redistribute it and/or modify                     #
# it under the terms of the GNU General Public License as published by            #
# the Free Software Foundation, either version 3 of the License, or               #
# (at your option) any later version.                                             #
#                                                                                 #
# UCK is distributed in the hope that it will be useful,                          #
# but WITHOUT ANY WARRANTY; without even the implied warranty of                  #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                   #
# GNU General Public License for more details.                                    #
#                                                                                 #
# You should have received a copy of the GNU General Public License               #
# along with UCK.  If not, see <http://www.gnu.org/licenses/>.                    #
###################################################################################
#############################
# general purpose functions #
#############################
function usage()
{
	echo "Usage: $0 [-m] iso-file.iso [remaster-dir]"
}
function failure()
{
	echo "$@"
	exit 1
}
#########################
# input parameter check #
#########################
use_mount=false
if [ x"$1" = x-m ]; then
	use_mount=true; shift
fi
ISO_IMAGE="$1"
REMASTER_HOME="$2"
if [ -z "$ISO_IMAGE" ]; then
	usage
	exit 1
fi
if [ -z "$REMASTER_HOME" ]; then
	REMASTER_HOME=~/tmp
fi
########
# main #
########
. libraries/remaster-live-cd.sh 2>/dev/null ||
	. /usr/lib/uck/remaster-live-cd.sh 2>/dev/null ||
	failure "libraries not found"
ISO_REMASTER_DIR="$REMASTER_HOME/remaster-iso"
ISO_MOUNT_DIR="$REMASTER_HOME/remaster-iso-mount"
# Check for previous use of union mounts and implicitly turn on -m iff found
if [ -d "$ISO_REMASTER_DIR"-cache ]; then
	use_mount=true
fi
if [ $use_mount = true ] && check_union_mounts; then
	# Mount r/w copy of iso
	if mountpoint "$ISO_REMASTER_DIR"; then
		: do nothing - is already mounted
	else
		union_mount "$ISO_IMAGE" "$ISO_REMASTER_DIR" ||
			failure "Can't union_mount $ISO_REMASTER_DIR"
	fi
	manifest_diff
	# Prevent immediate unmount by cleanup code
	trap : EXIT
else
	if [ $use_mount = true ]; then
		echo "Cannot use union mounts - using copy instead!"
		use_mount=false
	fi
	remove_iso_remaster_dir
	mount_iso
	unpack_iso
	unmount_iso
fi
 |