losetup - set up and control loop devices
SYNOPSIS
losetup [ -e encryption ] [ -o offset ] loop_device file
losetup [ -d ] loop_device
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 loop_device
argument is given, the status of the corresponding loop
device is shown.
OPTIONS
-d detach the file or device associated with the spec
ified loop device.
-e encryption
enable data encryption. The following keywords are
recognized:
NONE use no encryption (default).
XOR use a simple XOR encryption.
DES use DES encryption. DES encryption is only
available if the optional DES package has
been added to the kernel. DES encryption
uses an additional start value that is used
to protect passwords against dictionary
attacks.
-o offset
the data start is moved offset bytes into the spec
ified file or device.
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 losetup from determining the status of the
device.
FILES
/dev/loop0,/dev/loop1,... loop devices (major=7)
EXAMPLE
If you are using the loadable module you must have the
module loaded first with the command
# insmod loop.o
The following commands can be used as an example of using
the loop device.
losetup -e des /dev/loop0 /file
Password:
Init (up to 16 hex digits):
mkfs -t ext2 /dev/loop0 100
mount -t ext2 /dev/loop0 /mnt
...
umount /dev/loop0
losetup -d /dev/loop0
If you are using the loadable module you may remove the
module with the command
# rmmod loop
RESTRICTION
DES encryption is painfully slow. On the other hand, XOR
is terribly weak.
AUTHORS
Original version: Theodore Ts'o <tytso@athena.mit.edu>
Original DES by: Eric Young <eay@psych.psy.uq.oz.au>
Man(1) output converted with
man2html