|
|
losetup — set up and control loop devices
losetup loopdev
losetup −l [−a]
losetup −j file [ −o offset ]
losetup −d loopdev...
losetup −D
losetup −f
losetup [
−o offset ] [
−−sizelimit
size ] [ −p pfd ]
[−rP] −f [−−show] | loopdev
file
losetup −c loopdev
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.
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. losetup -a -l).
+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,
−−allshow status of all loop devices. Note that not all
information are accessible for non-root users. See also
−−list. The old
output format (as printed without --list) is
deprecated.
−c,
−−set−capacity
loopdevforce loop driver to reread 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−alldetach all associated loop devices
−f,
−−findfind the first unused loop device. If a file argument is present,
use this device. Otherwise, print its name
−h,
−−helpprint help
−j,
−−associated fileshow status of all loop devices associated with
given file
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. See also −−output, −−noheadings and
−−raw.
−n,
−−noheadingsdon't print headings for −−list output format
−o,
−−offset offsetthe data start is moved offset bytes into the
specified file or device
−O,
−−output columnsspecify which columns are to be printed for the
−−list
output
−−sizelimit sizethe data end is set to no more than size bytes after the data
start
−P,
−−partscanforce kernel to scan partition table on newly created loop device
−−rawuse raw −−list output format
−r,
−−read−onlysetup read-only loop device
−−showprint device name if the −f option and a
file argument
are present.
−v,
−−verboseverbose mode
Cryptoloop is no longer
supported in favor of dm-crypt. For more details
see cryptsetup(8).
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 from determining the status of the device.
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