Provided by: mount_2.27.1-6ubuntu2_i386 bug

NAME

       losetup - set up and control loop devices

SYNOPSIS

       Get info:

            losetup loopdev

            losetup -l [-a]

            losetup -j file [-o offset]

       Detach a loop device:

            losetup -d loopdev...

       Detach all associated loop devices:

            losetup -D

       Print the name of the first unused loop device:

            losetup -f

       Set up a loop device:

            losetup [-o offset] [--sizelimit size]
                    [-Pr] [--show] -f|loopdev file

       Resize a loop device:

            losetup -c loopdev

DESCRIPTION

       losetup  is  used to associate loop devices with regular files or block
       devices, to detach loop devices, and to query  the  status  of  a  loop
       device.   If  only  the  loopdev  argument  is given, the status of the
       corresponding loop device is shown.  If no option is  given,  all  loop
       devices are shown.

       Note  that the old output format (i.e. losetup -a) with comma-delimited
       strings is deprecated in favour of the --list output format.

OPTIONS

       The size and offset arguments may be  followed  by  the  multiplicative
       suffixes  KiB  (=1024),  MiB (=1024*1024), and so on for GiB, TiB, PiB,
       EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same  meaning
       as  "KiB")  or  the suffixes KB (=1000), MB (=1000*1000), and so on for
       GB, TB, PB, EB, ZB and YB.

       -a, --all
              Show the  status  of  all  loop  devices.   Note  that  not  all
              information  is accessible for non-root users.  See also --list.
              The old output format (as printed without --list) is deprecated.

       -c, --set-capacity loopdev
              Force the loop driver to reread the size of the file  associated
              with the specified loop device.

       -d, --detach loopdev...
              Detach  the  file  or  device associated with the specified loop
              device(s).

       -D, --detach-all
              Detach all associated loop devices.

       -f, --find
              Find the first unused  loop  device.   If  a  file  argument  is
              present,  use  the found device as loop device.  Otherwise, just
              print its name.

       -j, --associated file
              Show the status of all loop devices associated  with  the  given
              file.

       -J, --json
              Use JSON format for --list output.

       -l, --list
              If a loop device or the -a option is specified, print the
              default columns for either the specified loop  device  or
              all  loop devices; the default is to print info about all
              devices.  See  also  --output,  --noheadings  --json  and
              --raw.

       -n, --noheadings
              Don't print headings for --list output format.

       -o, --offset offset
              The  data  start is moved offset bytes into the specified
              file or device.

       -O, --output columns
              Specify the columns that are to be printed for the --list
              output.

       -P, --partscan
              Force  the  kernel to scan the partition table on a newly
              created loop device.

       --raw  Use the raw --list output format.

       -r, --read-only
              Set up a read-only loop device.

       --sizelimit size
              The data end is set to no more than size bytes after  the
              data start.

       --show Display  the  name  of the assigned loop device if the -f
              option and a file argument are present.

       -v, --verbose
              Verbose mode.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

ENCRYPTION

       Cryptoloop is no longer supported in  favor  of  dm-crypt.   For
       more details see cryptsetup (8).

RETURN VALUE

       losetup  returns 0 on success, nonzero on failure.  When losetup
       displays the status of a loop device, it returns 1 if the device
       is  not  configured  and  2 if an error occurred which prevented
       determining the status of the device.

FILES

       /dev/loop[0..N]
              loop block devices

       /dev/loop-control
              loop control device

EXAMPLE

       The following commands can be used as an example  of  using  the
       loop device.

              # dd if=/dev/zero of=~/file.img bs=1MiB count=10
              # losetup --find --show ~/file.img
              /dev/loop0
              # mkfs -t ext2 /dev/loop0
              # mount /dev/loop0 /mnt
               ...
              # umount /dev/loop0
              # losetup --detach /dev/loop0

ENVIRONMENT

       LOOPDEV_DEBUG=all
              enables debug output.

AUTHORS

       Karel  Zak <kzak@redhat.com>, based on the original version from
       Theodore Ts'o <tytso@athena.mit.edu>

AVAILABILITY

       The losetup command is part of the  util-linux  package  and  is
       available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.