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Linux Storage Loop Devices

losetup — manage loop devices

losetup associates regular files with loop devices, allowing disk image files to be treated as block devices.

What losetup is good for

Incorrect loop mapping can cause data corruption. Always verify which loop device you are using.

10 Practical Examples

1) List loop devices

losetup -a

2) Associate image with next free loop device

sudo losetup -f image.img

3) Show next free loop device

losetup -f

4) Attach file explicitly

sudo losetup /dev/loop0 image.img

5) Mount image via loop

sudo mount -o loop image.img /mnt/test

6) Detach loop device

sudo losetup -d /dev/loop0

7) Detach all unused loop devices

sudo losetup -D

8) Read-only attach

sudo losetup -r /dev/loop0 image.img

9) Handle partitioned images

sudo losetup -Pf image.img

Creates loop partitions (e.g., /dev/loop0p1).

10) Verify mapping

lsblk
losetup -a