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losetup


SYNOPSIS

       Get info:

            losetup loopdev

            losetup -l [-a]

            losetup -j file [-o offset]

       Delete loop:

            losetup -d loopdev...

       Delete all used loop devices:

            losetup -D

       Print name of first unused loop device:

            losetup -f

       Set up a loop device:

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

       Resize 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 corre-
       sponding loop device is shown.

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


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 status of all loop devices. Note that not  all  information
              are accessible for non-root users. See also --list. The old out-
              put format (as printed without --list) is deprecated.
              present, use this device. Otherwise, print its name

       -h, --help
              print help

       -j, --associated file
              show status of all loop devices associated with given file

       -l, --list
              if  a  loop  device or the -a option is specified, print default
              columns for  either  the  specified  loop  device  or  all  loop
              devices, default is to print info about all devices.

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

       -O, --output columns
              specify which columns are to be printed for the --list output

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

       -P, --partscan
              force  kernel  to  scan  partition  table  on newly created loop
              device

       -r, --read-only
              setup read-only loop device

       --show print device name if the -f  option  and  a  file  argument  are
              present.

       -v, --verbose
              verbose mode


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 config-
       ured and 2 if an error occurred which prevented  from  determining  the
       status of the device.


FILES

       /dev/loop[0..N]
              # mount /dev/loop0 /mnt
               ...
              # umount /dev/loop0
              # losetup --detach /dev/loop0


AUTHORS

       Karel Zak <kzak@redhat.com>, based on 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/.


util-linux July 2003 LOSETUP(8)



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