xorriso-dd-target - Man Page

The most simple and most boring use case is a program run without device names and without options -list_all, -plug_test, -DO_WRITE, -dummy_force. It prints on standard output (stdout) only the names of advisable devices without "/dev/" prefix. One name per line and without any reasoning text.
The possible sudo password prompt, the message line about sudo, and the empty line after it do not go to stdout.
Example:
$ xorriso-dd-target -with_sudo
Testing sudo to possibly get password prompting done now:
[sudo] password for thomas:
sudo /bin/lsblk seems ok.

sde

For the more curious user, there is option -list_all which prints the evaluation of each disk-like device that is listed by program lsblk. Optical drives, floppy disks, RAM block devices, loop devices are excluded, though.
Each device is shown by one line of the form
 name : advice : reasoning : info
name is the device name without "/dev/" prefix.
advice is either "YES" or "NO". "YES" indicates that the device appears to be pluggable disk-like, not used as system disk or sincere data storage, and - if tested - of sufficient or plausible size.
reasoning is a blank separated list of words with either suffix '+' for an inviting device property or '-' for a prohibitive property. Normally a single '-' reason disqualifies the device from being advisable. Only if option -look_for_iso is given, a reason "has_XYZ-" can be overridden by the presence of an ISO 9660 filesystem on the device.
info is composed from VENDOR and MODEL as told by lsblk.
Option -list_long causes with each line an additional listing of the information provided by lsblk which led to the shown reasons.
Example:
$ xorriso-dd-target -with_sudo -list_all
...
sda : NO  : not_usb- has_vfat+ has_ext4- : ATA Samsung SSD 850
sdb : NO  : not_usb- has_swap- has_ext4- : ATA WDC WD20EFRX-68A
sdc : YES : usb+ has_iso9660+ has_vfat+ : Intenso Ultra Line
sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2- : SanDisk Cruzer

If device names are given instead of option -list_all, then only these devices are inspected. Their result gets listed without the ": info" part, unless option -with_vendor_model is given.
Device names must not begin by '-' and must be single words composed of the characters [A-za-z0-9_/-]. They should not contain '/'. E.g. 'sdc' is valid, '/dev/sdc' is not valid.
If one of the given device names gets not advised, the exit value is 1.
It makes few sense to give device names which are not listed by -list_all.
Examples:
$ xorriso-dd-target -with_sudo sdc
...
sdc : YES : usb+ has_iso9660+ has_vfat+
$ xorriso-dd-target -with_sudo -with_vendor_model sdc
...
sdc : YES : usb+ has_iso9660+ has_vfat+ : Intenso Ultra Line
$ xorriso-dd-target sdc
sdc : NO  : usb+ no_fs_while_not_su-

Option -plug_test triggers an interactive method to unambiguously determine the intended target device candidate. It consists of 2 or 3 steps.
Step 1 is to have the intended storage device unplugged and to confirm this by pressing the Enter key at the program's prompt. The program will then assess the list of not wanted devices.
Step 2 is to plug in the intended storage device and to confirm this by pressing the Enter key a second time. The program will wait up to 10 seconds for a disk-like storage device which is not in the list of not wanted devices. The user may wait with key pressing until the device blinking looks like it is ready.
Only if a single new device is found, the program will go on as if a single device name was given. Option -list_all and any device names given as arguments will be ignored.
Step 3 happens only if options -DO_WRITE or -dummy_force are given. The program asks for a final input of the word 'yes' before real or simulated writing begins.
Example:
$ xorriso-dd-target -with_sudo -plug_test
...
Caused by option -plug_test: Attempt to find the desired device by watching it appear after being plugged in.
Step 1:
Please make sure that the desired target device is plugged _out_ now.
If it is currently plugged in, make sure to unmount all its filesystems
and then unplug it.
Press the Enter key when ready.

Found and noted as _not_ desired:  sda sdb sdc  
Step 2:
Please plug in the desired target device and then press the Enter key.

Waiting up to 10 seconds for a new device to be listed ... found: sdd
Now waiting 5 seconds to let it settle .........
Found and noted as desired device:  sdd

sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2- : SanDisk Cruzer

Only if option -DO_WRITE is given and -list_all is not, and if exactly one advisable device is listed, it really gets overwritten by the file content of the given -image_file. In this case the exit value is zero if writing succeeded, non-zero else.
Option -dummy prevents this kind of real action and rather shows the planned umount and dd commands on stdout.
Example:
$ xorriso-dd-target -with_sudo -plug_test -DO_WRITE \
   -image_file debian-live-10.0.0-amd64-xfce.iso
... sudo messages and above plug test steps 1 and 2 ...

sde : YES : usb+ has_iso9660+ has_vfat+
Step 3:
Last chance to abort. Enter the word 'yes' to start REAL WRITING.
yes
Looking for mount points of sde:
 /dev/sde1 on /mnt/iso type iso9660 (ro,relatime)
 /dev/sde2 on /mnt/fat type vfat (rw,...,errors=remount-ro)
Unmounted: /dev/sde1
Unmounted: /dev/sde2
Performing:
 sudo /bin/dd if=/dev/zero of=/dev/'sde' bs=512 seek='245759999'
              count=1 status=none
 sudo /bin/dd if='debian-live-10.0.0-amd64-xfce.iso' of=/dev/'sde'
              bs=1M status=progress oflag=dsync ; sync
... dd messages ...
The first dd run shall erase a possible GPT backup header. It is performed only if the local program "expr" can deal with the byte size of the device.

There should be no way to convince xorriso-dd-target of writing to a target device which it does not deem advisable. Please report any set of arguments that can be misused for that.
The outmost complicity to potentially unwise actions is offered by option -dummy_force. If given together with a single device name or with option -plug_test it will act like -dummy -DO_WRITE with this device, even if it looks not advisable. I.e. it will show the shell commands which the program does not dare to perform.
Example:
$ xorriso-dd-target -with_sudo -list_long -dummy_force sdd \
   -image_file debian-live-10.0.0-amd64-xfce.iso
...
sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2-
NAME    SIZE FSTYPE  TRAN LABEL
sdd     3.8G iso9660 usb  d-live 9.5.0 xf i386
|-sdd1  1.9G iso9660      d-live 9.5.0 xf i386
|-sdd2  320K vfat        
`-sdd3  512M ext2        

Overriding any advice because of -dummy_force
Looking for mount points of sdd:
 /dev/sdd1 on /mnt/iso type iso9660 (ro,relatime)
 /dev/sdd2 on /mnt/fat type vfat (rw,...,errors=remount-ro)
 /dev/sdd3 on /mnt/ext type ext2 (rw,relatime)
AGAINST THE ADVICE BY THIS PROGRAM, a daring user could do:
 sudo /bin/umount /dev/sdd1
 sudo /bin/umount /dev/sdd2
 sudo /bin/umount /dev/sdd3
 sudo /bin/dd if=/dev/zero of=/dev/'sdd' bs=512 seek='7864318'
              count=1 status=none
 sudo /bin/dd if='debian-live-10.0.0-amd64-xfce.iso' of=/dev/sdd
              bs=1M status=progress oflag=dsync ; sync
BE SMART. BE CAUTIOUS. BEWARE.

As stated with use case "List all devices", reasons are words with either suffix '+' for an inviting device property or '-' for a prohibitive property.
Normally a single '-' reason disqualifies the device from being advisable.

has_XYZ-
A filesystem of type XYZ is detected on base device or partition and is spoiling the impression of a device with disposable content.
has_iso9660+
An ISO 9660 filesystem is detected.
has_vfat+
A FAT (MS-DOS-like) filesystem is detected.
look_for_iso++
Option -look_for_iso is given and an ISO 9660 filesystem is detected. This reason overrides any "has_XYZ-" reason.
looks_like_cd_drive-
A given device name looks like the name of an optical drive: sr[0-9]*. Use program xorrecord for this kind of devices.
looks_like_disk_partition-
A given device name looks like the name of a partition. Expected are names of base devices, like "sde", not of their partitions, like "sde1".
looks_like_floppy-
A given device name looks like the name of a floppy disk drive: fd[0-9]*.
looks_like_loopdev-
A given device name looks like the name of a loop device: loop[0-9]*.
looks_like_ramdev-
A given device name looks like the name of a RAM block device: zram[0-9]*.
lsblk_no_size-
A size test is given by -max_size, -min_size, or -image_file but the size of the device cannot be inquired by lsblk. This is supposed to happen only with given inappropriate device names.
mmcblk+
The device name looks like a directly connected memory card.
name_with_slash-
A given device name contains '/' characters.
no_bus_info-
The device is not a memory card and lsblk reports nothing about the way how it is connected to the computer.
no_fs_while_not_su-
No filesystem is reported by lsblk and the program does not believe to have run it with superuser powers. There is the risk that lsblk silently failed to detect existing filesystems.
no_iso9660-
Option -look_for_iso is given but no ISO 9660 filesystem is detected.
not_usb-
The device is not a memory card and lsblk reports that it is connected by something other than USB.
size_too_large-
Option -max_size is given with a size smaller than the size of the device.
size_too_small-
Option -min_size or -image_file is given with size or file size larger than the size of the device.
usb+
The device is reported by lsblk to be connected via USB.