losetup 命令

常用示例

说明

losetup sets up and controls loop devices, which allow regular files to be accessed as block devices. This is commonly used for mounting disk images, ISO files, or encrypted containers.

参数

-a, --all

Show status of all attached loop devices.

-f, --find

Find the first unused loop device. With no other arguments, print its name; with a backing file, attach the file to it.

-P, --partscan

Force the kernel to scan the partition table on the newly created loop device.

-r, --read-only

Set up a read-only loop device.

-d, --detach _loopdev_

Detach the specified loop device.

-D, --detach-all

Detach all currently attached loop devices.

-j, --associated _file_

Show loop devices associated with _file_.

--show

Print the assigned device name (useful together with -f).

-o, --offset _bytes_

Start the loop device at _bytes_ offset into the backing file.

--sizelimit _bytes_

Limit the loop device to _bytes_ starting at offset.

-b, --sector-size _bytes_

Set the logical sector size (512, 1024, 2048, or 4096).

--direct-io=on|off

Enable or disable kernel direct I/O on the backing file.

-c, --set-capacity _loopdev_

Force the kernel to reread the size of the backing file.

-L, --nooverlap

Fail if any existing loop device already covers the same byte range of the backing file.

-O, --output _columns_

Specify which columns to print (use `--list --output list` to see available).

-l, --list

Use a listing format similar to `losetup -a` but with extra columns.

-J, --json

Output as JSON (use with --list).

--help

Display help information.