A loop device allows any file to be mounted as a filesystem image. Not to be confused with a loopback interface in networking.

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What is a “loop device” when mounting?

I am doing a mounting of an iso file and looking at this tutorial. They use the command: $ mount -o loop disk1.iso /mnt/disk I'm trying to understand the use of -o loop. So I have two questions: ...
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3answers
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How to setup a growable loopback device?

I know I can create and use a loopback device like this: # Create the file truncate disk.img --size 2G # Create a filesystem mkfs.ext4 disk.img # Mount to use mount disk.img /mnt # Clean up umount ...
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Creating formatted partition from nothing

I need to create filesystem with just one partition from nothing (/dev/zero). I tried this sequence of commands: dd if=/dev/zero of=mountedImage.img bs=512 count=131072 fdisk mountedImage.img n ...
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When mounting, when should I use a loop device?

According to the following question: What is a "loop device" when mounting? A loop device is a file that acts as a block-based device. While I can understand that conceptually, how is this ...
8
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Mounting multiple img files as single loop device

Is there a way to take a disk img file that is broken up into parts and mount it as a single loop device?
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GNU/Linux: overlay block device / stackable block device

GNU/Linux has union mount that overlays dirs. So you can mount a writeable dir on top of a read-only dir. When the writeable dir is unmounted the read-only dir is untouched. I am looking for the same ...
6
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How to atomically allocate a loop device?

I am writing some shell scripts to handle some disk image stuff, and I need to use loop devices to access some disk images. However, I am not sure how to properly allocate a loop device without ...
6
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1answer
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Mounting an old floppy image file (.ima format) - how hard can it be?

I'm trying to mount and access a floppy image file in the .ima format (raw dump to floppy, similar to .img) on ArchLinux. This file is part of a set of 30. It is not bootable, but rather a ...
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How can I mount partitons in a full disk image (i.e. image with partition table) with fuse?

It's a bit indirect, but it's possible mount a partition with a disk image using mount or losetup's "offset" parameter. I'm looking to be able to use fuse to do the same thing in user space Use ...
4
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2answers
638 views

loop-device: is this a Linux entity or a lower-level one?

Here's an Ubuntu How-to about booting from ISO-image on flash. http://ubuntuforums.org/showthread.php?t=1288604 What I don't get is creation of loop-device in GRUB2 prior to booting a kernel: ...
4
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Finding the offset for ext4 partition

I've created an image of my hd with dd, but grub was installed on it, and I'm trying to figure out how to mount the image file, but mount doesn't recognise it as an ext4 partition because of the grub ...
4
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767 views

How can I partition a volume in a regular file without loop?

I'm trying to play around with OS development, and I started with a boot loader, where phase 0 loads phase 1 from a file (specified by inode) on an ext4 partition (specified by first LBA). Of course, ...
4
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1answer
453 views

Virtual file made out of smaller ones (for mac-like sparse bundle solution)

I'd like to recreate a feature of Mac OS X called sparse bundles (disk images made out of smaller files, making them easy to backup after a small change). For that I'm looking for a way to ...
3
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3answers
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How to add more /dev/loop* devices on Fedora 19

How to add more /dev/loop* devices on Fedora 19? I do: # uname -r 3.11.2-201.fc19.x86_64 # lsmod |grep loop # ls /dev/loop* /dev/loop0 /dev/loop1 /dev/loop2 /dev/loop3 /dev/loop4 /dev/loop5 ...
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creating a device image for a network location

I have a dedicated ubuntu server with hetzner.de. hetzner also provides a seperate backup space accessible via samba/ftp/sftp/scp. In their support document about backups, the following line is ...
3
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1answer
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How do I setup more then 10 loopback device?

From this answer the solution is to modprobe loop max_loop=64 Which makes me allowed to use 64 loopback devices then mknod -m 660 /dev/loop8 b 7 8 To create the devices. I did this for 8, 9, 10 ...
3
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711 views

How to remove length limit from losetup -a

I am using losetup -a to see my loop devices, but it has a length limit (which is 62 characters). So I can't know for sure which loop device I really want. Ex: [root@r7byach]# losetup -a ...
3
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1answer
50 views

How to find which images belong to which /dev/loop?

I work a lot with imaged drives, meaning a do a dd-copy of the drive in question and then work on the image instead of the drive itself. For most work, I use kpartx to map the drive's partitions to a ...
3
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155 views

Source path of loop-device

Out of curiosity, I would like to know is there any way to find out the source of mounted partition ? e.g. Output of df -h is : /dev/loop1 3M 3M 0 100% /media/loop From this output, I know a ...
3
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3answers
119 views

Create Linux distro with minimal number of files

I'm thinking about designing a system for a project using some single-board computer (RaspberryPi, CubieTruck etc) that runs Linux. My main requirement is keeping the complexity of the booted SD card ...
3
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2answers
585 views

How to add a ms-dos partition table to a loop device?

I recently made a dd from a disk partition. I want to use it as a disk in a virtual machine. I can't because the disk has no partition table. Can I had a partition table to a loop device? how? ...
3
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1answer
64 views

How to make sure a loopfile is only mounted once?

When mounting a filesystem image via mount -o loop, is there any mechanism to prevent the same file to be mounted a second time?
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Provide loop device functionality for a regular file under a unique name

I want to add a few image files with file systems to a LVM volume group. If I make them available as loop devices changes are pretty high that one day the script gets corrupted due to an increasing ...
2
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2answers
185 views

Loop Mounting in Parallel

I am doing a project in which I need to mount 100+ loop devices and merge it into AUFS mountpoint As an observation, for sequentially mounting 90 loop devices, it takes 25 seconds. I am looking for ...
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How to iterate through a comma-separated list and execute a command for each entry

I have been give a command which outputs a comma-separated list for autosys jobs in the variable $all_jobs: box=box-of-jobs;all_jobs=$(jobscout -box $box | egrep "^\w+" | tr '\n' ',' | sed s/.$//); ...
2
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3answers
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Ensure that loopback root and host are unmounted on shutdown

I'm trying to setup a Linux system that runs from an LVM-formatted image file. After some tinkering with the initramfs and boot options I managed to make it up and running by mounting the host file ...
2
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2answers
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How is the loopback network interface implemented?

The loopback network interface "is a virtual network device implemented entirely in software," according to another question on Unix.SE. But how is this implementation actually accomplished, and how ...
2
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2answers
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Mount an ISO virtually using /dev/sr0 device

I'm doing a study about how CD-ROM can be mounted virtually and all I could find out was mounting using loop devices. mount -o loop disk1.iso /mount-point This is fairly easy. I understand that ...
2
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1answer
268 views

mapping a split file to /dev/loop0

I have a iscsi disk 2TB large. I make backup of that disk every week. The backup script copies the image of the whole iscsi disk into a file on my NFS. Unfortunately, it does not copy the image in one ...
2
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2answers
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mount: could not find any free loop device

When I try to mount an ISO image with mount -o loop I get mount: could not find any free loop device Running losetup -a shows /dev/loop0: [0005]:2464 (/dev/sda1) /dev/loop1: [0005]:3439 ...
2
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1answer
55 views

Grub change loopback amount?

I'm having an issue with loopback. It looks like there is only 8. I did a search and apparently the problem is grub by default only has 8 loopback (devices?). If i look in /dev/ i see loop 0-7 so that ...
2
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1answer
633 views

unetbootin: cannot mount squashfs on loop device

Im having a bit of fun with unetbootin with linux mint 16 setup in it. However when I try run the default menu item I get an error that ends with this: can not mount /dev/loop0 ...
2
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1answer
179 views

File containing ext filesystem

Let's suppose I create a file, map it to /dev/loop0, and create a LUKS partition inside dd if=/dev/zero of=myfile bs=1M count=1000 losetup /dev/loop0 myfile cryptsetup -c aes-cbc-essiv:sha256 -s 256 ...
2
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2answers
209 views

Loop device with 4K sectors

Using the losetup command, you can turn a regular file into a pretend block device. You can then partition and format it like any other device. Is there some way to make Linux pretend that this ...
2
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1answer
232 views

How to find alternative superblocks in ext3 file system of partition-less qcow2?

I have an interesting case, where e2fsck refuses to recognize the file system inside a qcow2 image file. Using testdisk I am able to see the partition, so some markers would be left. The reason this ...
2
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2answers
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busybox initramfs loop mount

I'm trying to loop mount my root filesystem (a loop file) within a busybox initramfs. I try to run the command: mount /rootfs.raw /root ... which works on my Ubuntu laptop, however, I simply get ...
2
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2answers
559 views

Second loopback network interface (for netem)

I would like to add a second loopback network device on Linux, so that I have lo and (e.g.) lo2. This is so that I can use netem to simulate a throttled network over lo2 without compromising my ...
2
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2answers
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slitaz 4.0 grub2 loopback concatenate multiple initrd images

I'm trying to get slitaz 4.0 ISO to boot using a grub2 loopback on a multiboot USB; insmod font if loadfont /boot/grub/unicode.pf2 ; then insmod gfxterm # insmod efi_gop # insmod efi_uga ...
2
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2answers
176 views

Generating a .img from tarball: The /dev/loop devices

I'm trying to make a .img from a tarball using the following script I found: #!/bin/bash # Packages required # dosfstools parted # Can be run on any Linux system # loop.max_part=15 must be in ...
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3answers
634 views

how to pipe the output of cut to the foreach command?

I have the cut command I want that grabs the first word in each line of a file. I then want to put each word from the cut command into a foreach. I then want to do a grep command inside the body of ...
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3answers
515 views

Why does this work: “cp image.bin /dev/mapper/loop0p1”?

Why does this work? cp image.bin /dev/mapper/loop0p1 image.bin is a partition image. I have tried it and works, but why? Shouldn't a dd be used?
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298 views

How is the loopback device traffic allowed?

How can I allow the traffic to be sent on the loopback device (lo)? What is the iptables command for it?
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4answers
127 views

Executing a command within `if` statement and on success perform further steps

I was trying to execute a program which will create a directory on the basis of a complete path provided to it from the prompt and, if the directory already exists it will return an error (for ...
1
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1answer
355 views

How to achieve `losetup -a` behaviour with busybox?

busybox (at least version 1.7, which I'm bound to use) to not provide the losetup -a switch to obtain a list of currently used loop devices plus the associated filename. Is there any way to obtain ...
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1answer
45 views

BASH: looping through ls [duplicate]

I'm having trouble with this piece of code: 22 for filename in "$( ls "$1" | grep ".*\.flac$" )"; do 23 file_path="$1${filename}" 24 ffmpeg -i "${file_path}" -f ...
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1answer
113 views

Can't losetup anything on armhf NAS

I'm pretty new to linux and chrooted my NAS with armhf architecture and tried looping device: losetup -f losetup: Could not find any loop device. Maybe this kernel does not know about the loop ...
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1answer
654 views

Mount image user-readable with udisks2

Loop devices, i.e. for mounting raw disk images, can be managed without root privileges using udisks. For testing purposes, an image can be created and formatted like so: dd if=/dev/urandom ...
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How do users mount .bin/.cue or .iso with loopback device as read only?

Can users mount any of the following image files as read-only using a loopback device? If it is possible then can anyone give me examples?
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1answer
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Installing Arch Linux on an SSD

I'm making my way through this: https://wiki.archlinux.org/index.php/Beginners%27_guide I've done this successfully a couple of times when working with conventional HDDs but I've recently bought and ...
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Loopback (bind) mount automatically mounting additional ext4 USB drive

I have a USB (ext4) drive connected and it's registered in /etc/fstab. It mounts at /media/Backup fine. I want to mount a specific directory on that drive using a bind / loopback mount (this is ...