losetup: set up and control loop devices.
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 deviceis shown.
Tag | Description |
---|---|
-a, --all | show status of all loop devices. |
-c, --set-capacity loopdev | force 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 devices. |
-e, -E, --encryption encryption_type | enable data encryption with specified name or number. |
-f, --find | find the first unused loop device. If a file argument is 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. |
-o, --offset offset | the data start is moved offset bytes into the specified file or device. |
--sizelimit limit | the data end is set to no more than sizelimit bytes after the data start. |
-p, --pass-fd num | read the passphrase from file descriptor with number num instead of from the terminal. |
-r, --read-only | setup read-only loop device. |
--show | print device name if the -f option and a file argument are present.The short form of this option (-s) is deprecated. This short form could be in collision with Loop-AES implementation where the same option is used for --sizelimit.. |
-v, --verbose | verbose mode. |
Example-1:
To detach file or device associated with loop device :
# losetup -e des /dev/loop0 /file
OR
# losetup -d /dev/loop0
Example-2:
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/loop0Print