Mount a single partition from an image of an entire disk

For those of you out there with Raspberries Pi who want to mount your SD cards on your Linux VMs:

1. Get the partition layout of the image:

    $ sudo fdisk -lu sda.img
    ...
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    ...
      Device Boot      Start         End      Blocks   Id  System
    sda.img1   *          56     6400000     3199972+   c  W95 FAT32 (LBA)

2. Calculate the offset from the start of the image to the partition start:

    Sector size * Start = (in this case) 56 * 512 = 28672

3. Mount it on /dev/loop0 using the offset

    sudo losetup -o 28672 /dev/loop0 sda.img

4. Now the partition resides on /dev/loop0. You can fsck it, mount it etc:

    sudo fsck -fv /dev/loop0
    sudo mount /dev/loop0 /mnt

   and unmount it:

    sudo umount /mnt
    sudo losetup -d /dev/loop0

Super useful. Thanks arrange!