x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
LOSETUP(8) System Administration LOSETUP(8)
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 used 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 cor-
responding 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 informa-
tion 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.
-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 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 out-
put.
-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 dis-
plays 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
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/.
util-linux July 2014 LOSETUP(8)
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