#!/bin/bash

#Logical partition:
PART_NUM=5
#Extended partition:
EXT_PART_NUM=2

IMG_FILE=archlinux-hf-2013-07-22.img

dd if=/dev/zero of=$IMG_FILE bs=1024000 conv=notrunc seek=6000 count=1

PART_START=$(parted $IMG_FILE -ms unit s p | grep "^${PART_NUM}" | cut -f 2 -d:)
[ "$PART_START" ] || exit 1

EXT_PART_START=$(parted $IMG_FILE -ms unit s p | grep "^${EXT_PART_NUM}" | cut -f 2 -d:)
[ "$EXT_PART_START" ] || exit 1

fdisk $IMG_FILE <<EOF
p
d
$EXT_PART_NUM
n
e
$EXT_PART_NUM
$EXT_PART_START

n
l
$PART_START

p
w
EOF

sudo kpartx -av $IMG_FILE
sudo e2fsck -f /dev/mapper/loop0p$PART_NUM
sudo resize2fs /dev/mapper/loop0p$PART_NUM
sudo kpartx -dv $IMG_FILE