libisoburn/xorriso-dd-target/xorriso-dd-target.1

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.TH XORRISO-DD-TARGET 1 "Version 1.5.3, Dec 5, 2019"
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.SH NAME
xorriso\-dd\-target \-  Device evaluator and disk image copier for GNU/Linux
.SH SYNOPSIS
.B xorriso-dd-target
[ options ] [ device_names ]
.br
.SH DESCRIPTION
.PP
\fBxorriso\-dd\-target\fR
evaluates block devices of the Linux kernel whether they are suitable targets
for a disk image file and optionally copies the image file to one of them.
.br
It is specialized on the device names of the Linux kernel and uses the
capabilities of util\-linux program lsblk. Therefore it refuses to run on
non\-Linux kernels.
.br
.PP
The main purpose of xorriso\-dd\-target is to inspect the device files
of disk\-like storage media and to judge whether they look like removable
devices with disposable content.
.br
If a single plausible candidate is detected, then the program is willing to 
copy a disk image file onto it. This will overwrite or make inaccessible the 
previous partition table and all previous data content of the target device.
.br
\fBSuperuser power\fR is normally needed for filesystem type identification,
for possible unmounting, and for possible image writing.
Option \fB\-with_sudo\fR offers a way to gain this power only for those
tasks and to run the program elsewise with a normal user's power.
.br
If a particular disk image file is intended as copy source, then
its path should be given by option \-image_file, so that its size can be used
as decision criterion.
.PP
Following are use case descriptions with examples:
.br
- List plain device names
.br
- List all devices with reasoning
.br
- Evaluate particular given devices
.br
- Detect intended device by plugging
.br
- Write image to an advised device
.br
- Show commands for writing to a not advised device
.br
.SS
\fBList plain device names:\fR
.br
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.
.br
Example:
.br
$ xorriso\-dd\-target \-with_sudo
.br
Testing sudo to possibly get password prompting done now:
.br
[sudo] password for thomas: 
.br
sudo /bin/lsblk seems ok.

sde
.SS
\fBList all devices with reasoning:\fR
.br
For the more curious user, there is option \fB\-list_all\fR which prints
the evaluation of each disk\-like device that is listed by program lsblk.
Optical drives, floppy disks, RAM block devices are excluded, though.
.br
Each device is shown by one line of the form
.br
  name : advice : reasoning : info
.br
\fBname\fR is the device name without "/dev/" prefix.
.br
\fBadvice\fR 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.
.br
\fBreasoning\fR 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.
.br
\fBinfo\fR is composed from VENDOR and MODEL as told by lsblk.
.br
Example:
.br
$ xorriso\-dd\-target \-with_sudo \-list_all
.br
 ...
.br
sda : NO  : not_usb\- has_vfat+ has_ext4\- : ATA Samsung SSD 850 
.br
sdb : NO  : not_usb\- has_swap\- has_ext4\- : ATA WDC WD20EFRX\-68A 
.br
sdc : YES : usb+ has_iso9660+ has_vfat+ : Intenso Ultra Line 
.br
sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2\- : SanDisk Cruzer 
.SS
\fBEvaluate particular given devices:\fR
.br
If \fBdevice names\fR are given instead of option \-list_all, then only
these devices are inspected. Their result gets listed without the ": info"
part, unless option \fB\-with_vendor_model\fR is given.
.br
Device names must not begin by '\-' and must be single words. They must
not contain '/'. E.g. 'sdc' is valid, '/dev/sdc' is not valid.
.br
If one of the given device names gets not advised, the exit value is 1.
.br
It makes few sense to give device names which are not listed by \-list_all.
.br
Examples:
.br
$ xorriso\-dd\-target \-with_sudo sdc
.br
 ...
.br
sdc : YES : usb+ has_iso9660+ has_vfat+
.br
$ xorriso\-dd\-target sdc
.br
sdc : NO  : usb+ no_fs_while_not_su\-
.SS
\fBDetect intended device by plugging:\fR
.br
Option \fB\-plug_test\fR triggers an interactive method to unambiguously
determine the intended target device candidate. It consists of 2 or 3 steps.
.br
\fBStep 1\fR 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.
.br
\fBStep 2\fR 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.
.br
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.
.br
\fBStep 3\fR 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.
.br
Example:
.br
$ xorriso\-dd\-target \-with_sudo \-plug_test
.br
 ...
.br
Caused by option \-plug_test: Attempt to find the desired device
by watching it appear after being plugged in.
.br
Step 1:
.br
Please make sure that the desired target device is plugged _out_ now.
.br
If it is currently plugged in, make sure to unmount all its fileystems
.br
and then unplug it.
.br
Press the Enter key when ready.
.br
 
.br
Found and noted as _not_ desired:  sda sdb sdc  
.br
Step 2:
.br
Please plug in the desired target device and then press the Enter key.
.br
 
.br
Waiting up to 10 seconds for a new device to be listed ...
.br
Found and noted as desired device:  sdd
.br
 
.br
sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2\- : SanDisk Cruzer 
.SS
\fBWrite image to an advised device:\fR
.br
Only if option \fB\-DO_WRITE\fR 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.
.br
Option \fB\-dummy\fR prevents this kind of real action and rather shows the
planned umount and dd commands on stdout.
.br
Example:
.br
$ xorriso\-dd\-target \-with_sudo \-plug_test \-DO_WRITE \\
.br
    \-image_file debian\-live\-10.0.0\-amd64\-xfce.iso
.br
 ... sudo messages and above plug test steps 1 and 2 ...
.br
 
.br
sde : YES : usb+ has_iso9660+ has_vfat+ 
.br
Step 3:
.br
Last chance to abort. Enter the word 'yes' to start REAL WRITING.
.br
yes
.br
Looking for mount points of sde:
.br
  /dev/sde1 on /mnt/iso type iso9660 (ro,relatime)
.br
  /dev/sde2 on /mnt/fat type vfat (rw,...,errors=remount\-ro)
.br
Unmounted: /dev/sde1
.br
Unmounted: /dev/sde2
.br
Performing:
.br
  sudo /bin/dd if='debian\-live\-10.0.0\-amd64\-xfce.iso' bs=1M of=/dev/sde ; sync
.br
 ... dd messages ...
.SS
\fBShow commands for writing to a not advised device:\fR
.br
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.
.br
The outmost complicity to potentially unwise actions is offered by
option \fB\-dummy_force\fR. 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.
.br
Example:
.br
$ xorriso\-dd\-target \-with_sudo \-dummy_force sdd \\
.br
    \-image_file debian\-live\-10.0.0\-amd64\-xfce.iso
.br
 ...
.br
sdd : NO  : usb+ has_iso9660+ has_vfat+ has_ext2\- 
.br
 
.br
Overriding any advice because of \-dummy_force
.br
Looking for mount points of sdd:
.br
  /dev/sdd1 on /mnt/iso type iso9660 (ro,relatime)
.br
  /dev/sdd2 on /mnt/fat type vfat (rw,...,errors=remount\-ro)
.br
  /dev/sdd3 on /mnt/ext type ext2 (rw,relatime)
.br
AGAINST THE ADVICE BY THIS PROGRAM, a daring user could do:
.br
  sudo /bin/umount /dev/sdd1
.br
  sudo /bin/umount /dev/sdd2
.br
  sudo /bin/umount /dev/sdd3
.br
  sudo /bin/dd if='debian\-live\-10.0.0\-amd64\-xfce.iso' bs=1M of=/dev/sdd ; sync
.br
BE SMART. BE CAUTIOUS. BEWARE.
.SS
\fBAlphabetical List of positive and negative reasons:\fR
.br
As stated with use case "List all devices", \fBreasons\fR are words with
either suffix '+' for an inviting device property or '\-' for a prohibitive
property.
.br
Normally a single '\-' reason disqualifies the device from being advisable.
.br
.PP
\fBhas_XYZ\-\fR
.br
A filesystem of type XYZ is detected on base device or partition and is
spoiling the impression of a device with disposable content.
.br
\fBhas_iso9660+\fR
.br
An ISO 9660 filesystem is detected.
.br
\fBhas_vfat+\fR
.br
A FAT (MS\-DOS\-like) filesystem is detected.
.br
\fBlook_for_iso++\fR
.br
Option \-look_for_iso is given and an ISO 9660 filesystem is detected.
This reason overrides any "has_XYZ\-" reason.
.br
\fBlooks_like_cd_drive\-\fR
.br
A given device name looks like the name of an optical drive: sr[0\-9]*.
Use program \fBxorrecord\fR for this kind of devices.
.br
\fBlooks_like_floppy\-\fR
.br
A given device name looks like the name of a floppy disk drive: fd[0\-9]*.
.br
\fBlooks_like_ramdev\-\fR
.br
A given device name looks like the name of a ram block device: zram[0\-9]*.
.br
\fBlooks_like_disk_partition\-\fR
.br
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".
.br
\fBlsblk_no_size\-\fR
.br
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.
.br
\fBmmcblk+\fR
.br
The device name looks like a directly connected memory card.
.br
\fBname_with_slash\-\fR
.br
A given device name contains '/' characters.
.br
\fBno_bus_info\-\fR
.br
The device is not a memory card and lsblk reports nothing about the way how
it is connected to the computer.
.br
\fBno_fs_while_not_su\-\fR
.br
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.
.br
\fBno_iso9660\-\fR
.br
Option \-look_for_iso is given but no ISO 9660 filesystem is detected.
.br
\fBnot_usb\-\fR
.br
The device is not a memory card and lsblk reports that it is connected by
something other than USB.
.br
\fBsize_too_large\-\fR
.br
Option \-max_size is given with a size smaller than the size of the device.
.br
\fBsize_too_small\-\fR
.br
Option \-min_size or \-image_file is given with size or file size larger than
the size of the device.
.br
\fBusb+\fR
.br
The device is reported by lsblk to be connected via USB.
.br
.SS
.br
.SH OPTIONS
.br
.PP
.TP
\fB\-plug_test\fR
Find the target device by asking the user to press the Enter key when the
desired target is _not_ plugged in, to then plug it in, and to press Enter
again.
.br
This overrides device names and option \-list_all.
The found device is then shown with advice, vendor, and model.
.br
Option \-DO_WRITE is obeyed if given.
In this case, the word 'yes' has to be entered to let unmounting and writing
begin.
.TP
\fB\-list_all\fR
Print list of all found devices with advice, vendor and model. One per line.
Ignore any device names. Ignore \-DO_WRITE.
.TP
\fB\-with_vendor_model\fR
Print vendor and model with each submitted device name.
.TP
\fB\-max_size\fR n[M|G|T]
Set the upper byte size limit for advisable devices. Plain numbers get rounded
down to full millions. As suffix are recognized: M = million, G = billion,
T = trillion.
.br
Be generous to avoid problems with GB < GiB.
.TP
\fB\-min_size\fR n[M|G|T]
Set the lower byte size limit for advisable devices. After processing like
with \-max_size, one million gets added to the size limit.
.TP
\fB\-look_for_iso\fR
Demand presence of an ISO 9660 filesystem. If so, then any further filesystem
type is acceptable on that device.
.br
If this option is missing, only ISO 9660 and VFAT filesystems are accepted.
.TP
\fB\-with_sudo\fR
Run 'lsblk \-o FSTYPE' by sudo. If no filesystems are detected on a device while
the program has no superuser power, then the device is not advised. Option
\-with_sudo avoids this refusal without the need to run the whole
program as superuser.
.br
If \-DO_WRITE \-with_sudo is given, then the programs umount and dd will be run
by sudo, too.
.TP
\fB\-image_file\fR PATH
Set the path of the image file which shall be written to a device. Its size
will be set as \-min_size.
.TP
\fB\-DO_WRITE\fR
Write the given \-image_file to the one advisable device that is found. If more
than one such device is found, then they get listed but no writing happens.
.br
In this case, to get a real write run, consider unplugging unneeded devices,
or using option \-plug_test, or a re\-run with one of the advised device names
as additional argument.
.TP
\fB\-dummy\fR
Report the \-DO_WRITE actions but do not perform them.
.TP
\fB\-dummy_force\fR
If a single device name is given, do a run of \-dummy \-DO_WRITE even against
the advice of this program. This probably shows you ways to shoot your own
foot.
.TP
\fB\-help\fR
Print the help text to stdout and then end the program.
.SH EXAMPLES
Examples are given in the above description of use cases.
.SH FILES
For now, no files are defined for configuration.
.SH SEE ALSO
.BR lsblk(8),
.BR umount(8),
.BR dd(1),
.BR xorrecord(1)
.SH BUGS
To report bugs, request help, or suggest enhancements for
\fBxorriso\-dd\-target\fR, 
please send electronic mail to the public list <bug\-xorriso@gnu.org>.
If more privacy is desired, mail to <scdbackup@gmx.net>.
.br
Please describe what you expect the program to do, the program arguments
which you used, the messages of \fBxorrisodd\-target\fR, and the
undesirable outcome of your program run.
.br
Expect to get asked more questions before solutions can be proposed.
.SH AUTHOR
Thomas Schmitt <scdbackup@gmx.net>
.br
for libburnia\-project.org
.SH COPYRIGHT
Copyright (c) 2019 Thomas Schmitt
.br
Permission is granted to distribute this text freely. It shall only be
modified in sync with the technical properties of xorriso\-dd\-target.
If you make use of the license to derive modified versions of xorriso\-dd\-target
then you are entitled to modify this text under that same license.
.SH CREDITS
\fBxorriso\-dd\-target\fR is developed in cooperation with Nio Wiklund alias
sudodus.