Bdtyktl

Update for Ubuntu 16.04: With the new losetup this is now easier:

sudo losetup -Pf disk_image.raw

See the rest of the answer for older versions of Ubuntu.

An easy solution is using kpartx: it will figure out the partition layout and map each to a block devices. After that all you have to do is mount the one you want.

Open Terminal, locate the disk image, and enter this command:

$ sudo kpartx -av disk_image.raw 

add map loop0p1 (252:2): 0 3082240 linear /dev/loop0 2048

add map loop0p2 (252:3): 0 17887232 linear /dev/loop0 3084288

This created loop0p1 and loop0p2 under /dev/mapper. From the output you can see the sizes of the partitions which helps you identify them. You can mount the one you want with:

$ sudo mount /dev/mapper/loop0p2 /mnt

Alternatively, the block device is detected by Nautilus and you can mount it from the side bar:

When you are done, unmount what you mounted and remove the device mapping:

$ sudo umount /mnt

$ sudo kpartx -d disk_image.raw

Edit : works with util-linux >=2.21. At the time of writing ubuntu ships with version 2.20 only

From man losetup :

       -P, --partscan

          force kernel to scan partition table on newly created loop device

So just run

$ sudo losetup -f --show -P /path/to/image.img

to create device nodes for every partition of your disk image on the first unused loop device and print it to stdout.
If using /dev/loop0 device it will create at least /dev/loop0p1 that you will be able to mount as usual.

Try gnome-disk-image-mounter:

gnome-disk-image-mounter sda.img

No sudo required. It will be mounted at /media/your_user_name/partition_name, just like USB drives.

losetup -P automation

losetup -P is the best method starting in Ubuntu 16.04 as mentioned at https://askubuntu.com/a/496576/52975 , here are functions to automate if further. Usage:

$ los my.img

/dev/loop0

/mnt/loop0p1

/mnt/loop0p2



$ ls /mnt/loop0p1

/whatever

/files

/youhave

/there



$ sudo losetup -l

NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE                                                                                      DIO

/dev/loop1         0      0         0  0 /full/path/to/my.img



$ # Cleanup.

$ losd 0

$ ls /mnt/loop0p1

$ ls /dev | grep loop0

loop0

Source:

los() (

  img="$1"

  dev="$(sudo losetup --show -f -P "$img")"

  echo "$dev"

  for part in "$dev"?*; do

    if [ "$part" = "${dev}p*" ]; then

      part="${dev}"

    fi

    dst="/mnt/$(basename "$part")"

    echo "$dst"

    sudo mkdir -p "$dst"

    sudo mount "$part" "$dst"

  done

)

losd() (

  dev="/dev/loop$1"

  for part in "$dev"?*; do

    if [ "$part" = "${dev}p*" ]; then

      part="${dev}"

    fi

    dst="/mnt/$(basename "$part")"

    sudo umount "$dst"

  done

  sudo losetup -d "$dev"

)

loop module max_part config

This is a decent method before 16.04.

loop is a kernel module, built into the kernel in Ubuntu 14.04.

If you configure it right, Linux automatically splits up the devices for you.

cat /sys/module/loop/parameters/max_part

says how many partitions loop devices can generate.

It is 0 by default on Ubuntu 14.04 which is why no auto-splitting happens.

To change it, we can either add:

options loop max_part=31

to a file in /etc/modprobe, or:

GRUB_CMDLINE_LINUX="loop.max_part=31"

to /etc/default/grub and then sudo update-grub.

How to set a module parameter is also covered at: How to add kernel module parameters?

After a reboot, when you do:

sudo losetup -f --show my.img

it mounts the image to a /dev/loopX device, and automatically mounts the partitions to /dev/loopXpY devices.

So this is the most convenient method if you are willing to reboot.

See also

• https://unix.stackexchange.com/questions/9099/reading-a-filesystem-from-a-whole-disk-image


• https://superuser.com/questions/117136/how-can-i-mount-a-partition-from-dd-created-image-of-a-block-device-e-g-hdd-u


• Mount single partition from image of entire disk (device)


• https://stackoverflow.com/questions/1419489/loopback-mounting-individual-partitions-from-within-a-file-that-contains-a-parti

Use losetup to attach the whole disk image.

# sudo losetup /dev/loop2 sda.img

Then use mdadm to create an md device and block devices will be created for all of the partitions.

# sudo mdadm --build --level=0 --force --raid-devices=1 /dev/md2 /dev/loop2

mdadm: array /dev/md2 built and started.

Now you should see the partition devices.

nile-172-b0fef38-76:/mnt/sdb1 # ls -l /dev/md2*

brw-rw---- 1 root disk   9, 2 Oct 10 12:37 /dev/md2

brw-rw---- 1 root disk 259, 0 Oct 10 12:37 /dev/md2p1

The simplest way, in my opinion, is using mount -o loop,offset=... as mentioned in this answer on StackOverflow. The idea is as follows:

fdisk -l $IMAGE

# calculate the offset in bytes

mount -o loop,offset=$OFFSET $IMAGE $MOUNTPOINT

The method is best because it doesn't require deleting the loop device after you umount the mounted partition.

To further simplify the task (which is needed if you do it often), you may use my script mountimg to do everything for you. Just get it from https://github.com/AlexanderAmelkin/mountimg
and use like this:

mountimg /media/external_media/sda.img 2 /media/sda_image

You may as well specify filesystem type and any other additional mount options if you like:

mountimg /media/external_media/sda.img 2 /media/sda_image -t vfat -o codepage=866,iocharset=utf-8

When you're done with the partition, simply umount it:

umount /media/sda_image