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Updated: Wednesday, July 27, 2022
 
 

xorrisofs (1)

Name

xorrisofs - Emulation of ISO 9660 program mkisofs by program xorriso

Synopsis

xorrisofs [ options ] [-o filename ] pathspec [pathspecs ...]

Description

XORRISOFS(1)                General Commands Manual               XORRISOFS(1)



NAME
       xorrisofs -  Emulation of ISO 9660 program mkisofs by program xorriso

SYNOPSIS
       xorrisofs [ options ] [-o filename ] pathspec [pathspecs ...]

DESCRIPTION
       xorrisofs  produces Rock Ridge enhanced ISO 9660 filesystems and add-on
       sessions  to  such  filesystems.  Optionally  it  can  produce   Joliet
       directory trees too.

       xorrisofs understands options of program mkisofs from cdrtools by Joerg
       Schilling.  Its implementation is part of program xorriso which  shares
       no source code with cdrtools.

   ISO 9660, Rock Ridge, Joliet, HFS+:
       ISO  9660  (aka ECMA-119) is a read-only filesystem that is mainly used
       for optical media CD, DVD, BD, but may also  reside  on  other  storage
       devices  like  disk  files, USB sticks or disk partitions. It is widely
       readable by many operating systems and by boot facilities  of  personal
       computers.
       ISO  9660  describes  directories  and  data  files  by very restricted
       filenames with no distinction  of  upper  case  and  lower  case.   Its
       metadata do not comply to fundamental POSIX specifications.
       Rock Ridge is the name of a set of additional information which enhance
       an ISO 9660 filesystem so that  it  can  represent  a  POSIX  compliant
       filesystem  with  ownership,  access  permissions,  symbolic links, and
       other attributes.  Rock Ridge allows filenames of up to 255  bytes  and
       paths of up to 1024 bytes.
       xorrisofs  produces  Rock  Ridge information by default. It is strongly
       discouraged to disable this feature.
       Joliet is the name of  an  additional  directory  tree  which  provides
       filenames  up  to  64  characters  encoded as UTF-16.  A Joliet tree is
       mainly interesting for reading the ISO image by  operating  systems  of
       Microsoft  Corporation.   Production  of  this  directory  tree  may be
       enabled by option -J.
       ISO 9660:1999 is  the  name  of  an  additional  directory  tree  which
       provides  longer  filenames.  It allows single file names to have up to
       207 characters.  It might be of use with  some  older  computer  system
       boot  facilities  which  read  neither  Rock  Ridge nor Joliet but need
       longer filenames nevertheless.  Production of this directory  tree  may
       be enabled by option -iso-level 4.
       HFS+ is the name of a filesystem which is normally used for writing and
       reading on hard disks and similar devices. It is possible  to  embed  a
       HFS+ partition into the emerging ISO 9660 image and to mark it by Apple
       Partition Map entries. This interferes with  options  which  copy  data
       into  the first 32 KiB of the ISO image, like -G or -isohybrid-mbr. See
       option -hfsplus.
       The main purpose for having an embedded HFS+ partition  is  booting  of
       certain models of Apple computers.

   Inserting files into the ISO image:
       xorrisofs deals with two kinds of file addresses:
       disk_path is a path to an object in the local filesystem tree.
       iso_rr_path  is  the  Rock  Ridge  address  of a file object in the ISO
       image.  If no Rock Ridge information shall be  stored  in  an  emerging
       ISO, then the names will get mapped to ISO 9660 names of limited length
       and character set.

       A program argument is handled as a pathspec, if it is not recognized as
       original  mkisofs  option  or  additional xorrisofs option.  A pathspec
       depicts an input file object by a disk_path.  If  option  -graft-points
       is  not  present,  then  the  behavior  depends  on  the  file  type of
       disk_path. Directories get merged  with  the  /-directory  of  the  ISO
       image. Files of other types get copied into the /-directory.
       If  -graft-points is present then each pathspec gets split at the first
       occurrence of the =-character.  The part  before  the  =  is  taken  as
       target,  i.e. the iso_rr_path for the file object in the ISO image. The
       part after the first = is taken as source, i.e. the  disk_path  of  the
       input object.
       It  is  possible  to  make  =-characters  part  of  the  iso_rr_path by
       preceding  them  with  a  \-character.  The  same  must  be  done   for
       \-characters which shall be part of the iso_rr_path.

       If the source part of the pathspec leads to a directory, then all files
       underneath this directory get inserted into  the  image,  too.   It  is
       possible  to  exclude  particular  files from being inserted by help of
       option -m.
       In  case  that  target  already  exists,  the  following  rules  apply:
       Directories  and  other  files  may overwrite existing non-directories.
       Directories get merged with existing directories.  Non-directories  may
       not overwrite existing directories.

   Relation to program xorriso:
       xorrisofs  is  actually  a  command mode of program xorriso, which gets
       entered either by xorriso command "-as  mkisofs"  or  by  starting  the
       program  by  one of the names "xorrisofs", "mkisofs", "genisoimage", or
       "genisofs".
       This command mode can be left by argument "--" which leads  to  generic
       xorriso command mode. See man xorriso for its description.

       xorriso performs image reading and writing by help of libburn, which is
       mainly intended for optical drives, but also operates on all POSIX file
       types except directories.
       The  program  messages  call any image file a "drive". File types which
       are not supported for reading are reported  as  "blank".  The  reported
       free media space may be quite fictional.
       Nevertheless xorrisofs does not operate directly on optical drives, but
       rather forces libburn to regard them as general device files.   So  for
       writing  of  sequential optical media (CD, DVD-R, DVD+R, BD-R) one will
       have to use a burn program. E.g the cdrecord emulation of xorriso.  See
       EXAMPLES.


OPTIONS
       Image loading:

       The  following options control loading of an existing ISO image for the
       purpose of preparing a suitable add-on session.  If  they  are  missing
       then a new image is composed from scratch.

       -M disk_path
              Set the path from which to load the existing ISO image directory
              tree on which to base the  upcoming  directory  tree  as  add-on
              session.   The  path  must lead to a random-access readable file
              object.  On GNU/Linux: regular data files or block device files.
              A   special   kind   of   pseudo   disk_path   has   the    form
              "/dev/fd/"number.   It depicts the open file descriptor with the
              given number, regardless whether the operating  system  supports
              this feature by file nodes in /dev/fd or not.  E.g. /dev/fd/3 is
              file descriptor 3 which was opened by  the  program  that  later
              started xorriso.

       -prev-session disk_path
              Alias of -M.

       -dev disk_path
              Alias of -M.

       -C last_session_start,next_writeable_address
              Set  the  2  KiB  block address last_session_start from where to
              read the ISO image out of the file given by option -M.
              Separated by a comma, set the  next_writeable_address  to  which
              the add-on session will finally be written. Decisive is actually
              the block address which the intended readers will have to use as
              superblock address on the intended medium.
              Both  values  can be inquired from optical media by help of burn
              programs and cdrecord option -msinfo. xorriso itself can  obtain
              it in its cdrecord emulation.
                values=$(xorriso -as cdrecord dev=/dev/... -msinfo)
                echo $values
              Option  -C  may be used without option -M to create an ISO image
              from scratch and prepare it for being finally written to a block
              address  other than 0. Parameter last_session_start must then be
              set to 0.

       -cdrecord-params last_session_start,next_writeable_address
              Alias of -C.

       Settings for file insertion:

       -path-list disk_path
              Read  pathspecs  line-by-line  from  disk_file  and  insert  the
              depicted  file  objects  into the ISO image. If disk_path is "-"
              then read the pathspecs from standard input.

       --quoted_path_list disk_path
              Like option -path-list but  reading  quoted  words  rather  than
              plain lines.  Whitespace outside of quotes will be discarded. On
              the other hand it  is  possible  to  represent  pathspecs  which
              contain newline characters.
              The  double quotation mark " and the single quotation mark ' can
              be used to enclose whitespace and make  it  part  of  pathspecs.
              Each  mark  type  can  enclose  the  marks  of the other type. A
              trailing backslash \ outside quotations  or  an  open  quotation
              cause the next input line to be appended.

       -f
              Resolve  symbolic  links  on  disk  rather  than storing them as
              symbolic links in the ISO image.

       -follow-links
              Alias of -f.

       -graft-points
              Enable interpretation of input file pathspecs as combination  of
              iso_rr_path and disk_path, separated by a =-character.

       -m disk_pattern
              Exclude  files  from  being  inserted  into  the image. Silently
              ignored are those files of which the disk_path matches the given
              shell parser pattern.  If no /-character is part of the pattern,
              then it gets matched against the leaf name of the disk file.
              It is possible to give more than one -m option.

       -exclude
              Alias of -m.

       -x
              Alias of -m.

       -old-exclude
              Alias of -m.

       -exclude-list disk_path
              Perform -m using each line out of  file  disk_path  as  argument
              disk_pattern.

       -z
              Enable  recognition  and  proper processing of zisofs compressed
              files as produced by program  mkzftree.  These  files  will  get
              equipped  with  the  necessary  meta data so that a Linux kernel
              will recognize them and deliver their  content  in  uncompressed
              form.

       -transparent-compression
              Alias of -z.

       --zisofs-version-2
              Enable  the  recognition  and  proper processing of experimental
              zisofs version 2 compressed files.  The Linux kernel (as of 5.9)
              does not yet know this format and will complain like
                isofs: Unknown ZF compression algorithm: PZ
              This complaint can be prevented by option --zisofs2-susp-z2 .
              The  files  will  be  shown  by  unaware  kernels  as  they were
              submitted to xorriso, i.e. with zisofs2  header,  block  pointer
              list, and compressed data.
              --zisofs-version-2 also enables -z.

       --zisofs2-susp-z2
              Enable  the production of SUSP entries "Z2" instead of "ZF" with
              zisofs2 compressed files. Unaware Linux kernels silently  ignore
              "Z2" entries.

       --zisofs2-susp-zf
              Enable  the production of SUSP entries "ZF" instead of "Z2" with
              zisofs2 compressed files. Unaware Linux kernels  complain  about
              zisofs2  "ZF"  by  "Unknown  ZF  compression algorithm" and thus
              leave a mark in the system log.

       -root iso_rr_path
              Insert  all  files  under  the  given  iso_rr_path.  If   option
              -graft-points  is  given,  then iso_rr_path is prepended to each
              target part of a pathspec.
              The default for -root is "/".

       -old-root iso_rr_path
              Enable incremental insertion of files  into  the  loaded  image.
              The effective target and source addresses of given pathspecs get
              compared whether the target already exists in the ISO image  and
              is  still  identical  to the source on disk. Metadata in the ISO
              image will get adjusted, if they differ from those on disk.  New
              files  and  files  with  changed  content  will get newly added.
              Target files which do not exist in any of the according pathspec
              sources will get removed from the ISO directory tree.
              If  the  effective setting of -root differs from the iso_rr_path
              given with -old-root, then the files  underneath  the  -old-root
              directory  get  cloned  underneath  the -root directory. Cloning
              happens before file comparison.

       --old-root-no-ino
              Disable recording and use of disk inode  numbers.   If  no  disk
              inode  numbers  are recorded, then option -old-root will have to
              read disk file content and compare it with the MD5 checksum that
              is recorded in the ISO image.
              With  recorded  disk  inode  numbers and with credible ctime and
              mtime, it is possible to detect potential changes in the content
              without  actually  reading  it.   A loophole remains if multiple
              different filesystems may get mounted  at  the  same  directory,
              like  it is habit with /mnt.  In this case one has to use option
              --old-root-devno  or  disable  the  inode  number  shortcut   by
              --old-root-no-ino.

       --old-root-devno
              Enable  comparison  of  recorded  device  numbers  together with
              recorded inode numbers. This works only  with  good  old  stable
              device  numbers  which  get  out of fashion, regrettably. If the
              hard disk has a different device number after each reboot,  then
              this  comparison  will see all files as changed and thus prevent
              any incremental size saving.

       --old-root-no-md5
              Disable recording  and  use  of  MD5  checksums  for  data  file
              content.   If  neither  checksums and nor disk inode numbers are
              recorded, then option -old-root will have to read ISO image file
              content when comparing it with disk file content.

       Settings for image production:

       -o disk_path
              Set  the output file address for the emerging ISO image.  If the
              address exists as regular file, it will be truncated to length 0
              when  image  production  begins.  It  may  not  already exist as
              directory.  If it does not exist yet then its  parent  directory
              must exist and a regular file will get created.
              A    special   kind   of   pseudo   disk_path   has   the   form
              "/dev/fd/"number.  It depicts the open file descriptor with  the
              given  number,  regardless whether the operating system supports
              this feature by file nodes in /dev/fd or not.  E.g. /dev/fd/4 is
              file  descriptor  4  which  was opened by the program that later
              started xorriso.
              Default is standard output (/dev/fd/1) which may also be set  by
              disk_path "-".

       -output disk_path
              Alias of -o.

       --stdio_sync "on"|"off"|"end"|number
              Set  the  number of bytes after which to force output to disk in
              order to keep the memory from being clogged with lots of pending
              data for slow devices. "on" is the same as "16m".  Forced output
              can be disabled by "off", or be delayed by "end" until all  data
              are  produced.  If  a number is chosen, then it must be at least
              64k.
              The default  with  xorriso  mkisofs  emulation  is  --stdio_sync
              "off".
              xorriso  uses  an  inner fifo buffer with default size 4 MiB. So
              forcing  the  operating  system  i/o  cache  to  disk  does  not
              necessarily  block  the  simultaneous  production  of more image
              content.

       --emul-toc
              Write  a  second  superblock  with  the   first   session   into
              random-access  files.  If  further sessions get appended and the
              first superblock gets updated, then the second  superblock  will
              not  be  overwritten. So it is still possible to mount the first
              session and to find the start blocks of the further sessions.
              The   price   is   64   KiB   extra   space   consumption.    If
              -partition_offset is non-zero, then it is 128 KiB plus twice the
              partition setup.

       --no-emul-toc
              Do not write a second superblock with  the  first  session  into
              random-access files.
              This is the default.

       --sort-weight weight_number iso_rr_path
              Attribute  a  LBA weight number to regular files. If iso_rr_path
              leads to a directory then all regular files underneath will  get
              the weight_number.
              The weight_number may range from -2147483648 to 2147483647.  The
              higher it is, the lower will be the block address  of  the  file
              data  in  the  emerging ISO image.  Currently the El Torito boot
              catalog has a hardcoded weight of 1 billion.  Normally it should
              occupy  the  block with the lowest possible address.  Data files
              get added or loaded with initial weight 0. Boot image files have
              a default weight of 2.

       --sort-weight-list disk_path
              Read  pairs  of weight number and iso_rr_path from a file of the
              local filesystem. Apply each pair like with --sort-weight.
              Only the last --sort-weight-list or --sort-weight-patterns of  a
              xorrisofs run gets into effect.
              The  weight  number  is  read  from  the start of the line.  The
              iso_rr_path part of an input line begins immediately  after  the
              first blank or tab character of the line.
              Notes  for  the case that this feature is used within a sequence
              of generic xorriso commands (not an issue with  a  pure  mkisofs
              emulation run):
              The  addressed files must already be in the ISO image model when
              you execute
                -as mkisofs --sort-weight-list disk_path --
              Several such commands may be used to apply more than one  weight
              file.
              Data  files  which  are  loaded  by  -indev or -dev get a weight
              between 1 and 2 exp 28 = 268,435,456, depending on  their  block
              address.  This  shall keep them roughly in the same order if the
              write method of modifying is applied.

       --sort-weight-patterns disk_path
              Like --sort-weight-list ,  but  expanding  the  iso_rr_paths  as
              shell   parser  patterns  and  applying  --sort-weight  to  each
              matching file.

       -uid number|name
              Use the given number or locally existing user name as  owner  id
              of  all files and directories in the emerging filesystem.  Empty
              name or name "-" revoke this feature.

       -gid number|name
              Use the given number or locally existing group name as group  id
              of  all files and directories in the emerging filesystem.  Empty
              name or name "-" revoke this feature.

       -dir-mode mode
              Set the access permissions for all directories in the  image  to
              the  given  mode  which is either an octal number beginning with
              "0" or  a  comma  separated  list  of  statements  of  the  form
              [ugoa]*[+-=][rwxst]* . E.g. ug=rx,a-rwx

       -file-mode mode
              Like -dir-mode but for all regular data files in the image.

       -pad
              Add  300  KiB  to  the  end  of  the  produced  ISO  image. This
              circumvents possible read errors from ISO images which have been
              written  to  CD  media  in  TAO  mode.  The additional bytes are
              claimed as part of the ISO image if not --emul-toc is given.
              Option -pad is the default.

       -no-pad
              Disable padding of 300 KiB to the end of the produced ISO image.
              This is safe if the image is not meant to be written on CD or if
              it gets written to CD as only track in write mode SAO.

       --old-empty
              Use the old way of of giving block addresses  in  the  range  of
              [0,31] to files with no own data content. The new way is to have
              a dedicated block to which all such files will point.

       Settings for standards compliance:

       -iso-level number
              Specify the ISO 9660 version which defines  the  limitations  of
              file  naming  and data file size. The naming restrictions do not
              apply to the Rock Ridge names but only to the low-level ISO 9660
              names.  There are three conformance levels:
              Level  1  allows ISO names of the form 8.3 and file size up to 4
              GiB - 1.
              Level 2 allows ISO names with up to 32 characters and file  size
              up to 4 GiB - 1.
              Level 3  allows ISO names with up to 32 characters and file size
              of up to 400 GiB - 200 KiB. (This size limitation is set by  the
              xorriso  implementation  and  not  by ISO 9660 which would allow
              nearly 8 TiB.)
              Pseudo-level 4 enables production of an additional ISO 9660:1999
              directory tree.

       -disallow_dir_id_ext
              Do  not  follow  a bad habit of mkisofs which allows dots in the
              ISO names of directories.  On  the  other  hand,  some  bootable
              GNU/Linux images depend on this bad habit.

       -U
              This  option  allows  ISO  file  names  without dot and up to 37
              characters, ISO file paths longer than 255 characters,  and  all
              ASCII  characters  in file names. Further it omits the semicolon
              and the version numbers at the end of ISO names.
              This all violates ISO 9660 specs.

       -untranslated-filenames
              Alias of -U.

       -untranslated_name_len number
              Allow ISO file names  up  to  the  given  number  of  characters
              without  any character conversion. The maximum number is 96.  If
              a file name has more characters, then image production will fail
              deliberately.
              This violates ISO 9660 specs.

       -allow-lowercase
              Allow lowercase character in ISO file names.
              This violates ISO 9660 specs.

       -relaxed-filenames
              Allow  nearly  all  7-bit  characters  in  ISO  file names.  Not
              allowed are 0x0 and  '/'.  If  not  option  -allow-lowercase  is
              given, then lowercase letters get converted to uppercase.
              This violates ISO 9660 specs.

       -d
              Do not add trailing dot to ISO file names without dot.
              This violates ISO 9660 specs.

       -omit-period
              Alias of -d.

       -l
              Allow up to 31 characters in ISO file names.

       -full-iso9660-filenames
              Alias of -l.

       -max-iso9660-filenames
              Allow up to 37 characters in ISO file names.
              This violates ISO 9660 specs.

       -N
              Omit  the  semicolon  and  the version numbers at the end of ISO
              names.
              This violates ISO 9660 specs.

       -omit-version-number
              Alias of -N.

       Settings for standards extensions:

       -R
              With  mkisofs  this  option  enables  Rock   Ridge   extensions.
              xorrisofs  produces  them by default. It is strongly discouraged
              to disable them by option --norock.

       -rock
              Alias of -R.

       -r
              Enable Rock Ridge and set user and group id of all files in  the
              ISO   image   to  0.   Grant  r-permissions  to  all.  Deny  all
              w-permissions.  If any x-permission is set,  grant  x-permission
              to all.  Remove s-bit and t-bit.
              These  attribute  changes  stay  delayed until mkisofs emulation
              ends. Within the same -as mkisofs emulation command they can  be
              revoked  by  a  subsequent  option  --norock.  For compatibility
              reasons, option -R does not revoke the changes ordered by -r.

       -rational-rock
              Alias of -r.

       --norock
              This option disables the production of Rock Ridge extensions for
              the  ISO  9660  file  objects. The multi-session capabilities of
              xorrisofs depend much on the naming fidelity of Rock  Ridge.  So
              it  is strongly discouraged to disable it by this option, except
              for the special use case to revoke the effect of -r by:
               --norock -R

       --set_all_file_dates timestring
              Set mtime, atime, and ctime of all files and directories to  the
              given time.
              Valid  timestring  formats  are:  'Nov  8  14:51:13  CET  2007',
              110814512007.13, 2007110814511300. See also --modification-date=
              and man xorriso, Examples of input timestrings.
              If the timestring is "set_to_mtime", then the atime and ctime of
              each file and directory get set to  the  value  found  in  their
              mtime.
              These  actions  stay delayed until actual ISO production begins.
              Up to then they can  be  revoked  by  --set_all_file_dates  with
              empty timestring or timestring "default".
              The  timestamps of the El Torito boot catalog file get refreshed
              when  the  ISO  is  produced.  They   can   be   influenced   by
              --modification-date=.

       -file_name_limit number
              Set  the  maximum permissible length for file names in the range
              of 64 to 255.  Path components which are longer than  the  given
              number   will  get  truncated  and  have  their  last  33  bytes
              overwritten by a colon ':' and the hex representation of the MD5
              of  the  first 4095 bytes of the whole oversized name. Potential
              incomplete  UTF-8  characters  will  get  their  leading   bytes
              replaced by '_'.
              Linux  kernels  up  to at least 4.1 misrepresent names of length
              254 and 255.  If you expect such names in  or  under  disk_paths
              and plan to mount the ISO by such Linux kernels, consider to set
              -file_name_limit 253.

       -D     The standard ECMA-119 demands that no path in  the  image  shall
              have more than 8 name components or 255 characters. Therefore it
              would be necessary to move deeper directory trees  to  a  higher
              directory.  Rock  Ridge  offers  an  opportunity  to  let  these
              relocated directories appear at their  original  deep  position,
              but  this feature might not be implemented properly by operating
              systems which mount the image.
              Option -D disables this  deep  directory  relocation,  and  thus
              violates ISO 9660 specs.
              xorrisofs  has  -D  set  by default. If given explicitly then it
              overrides the options -rr_reloc_dir and -hide-rr-moved.

       -disable-deep-relocation
              Alias of -D.

       -rr_reloc_dir name
              Enable  the  relocation  of  deep  directories  and  thus  avoid
              ECMA-119  file  paths  of  more  than  8  name components or 255
              characters. Directories which lead to such file paths  will  get
              moved  to  a  directory  in the root directory of the image. Its
              name gets set by this option.  It is permissible to use the root
              directory itself.
              The  overall  directory  tree  will  appear originally deep when
              interpreted as Rock Ridge tree. It will appear as re-arranged if
              only ECMA-119 information is considered.
              If  the given relocation target directory does not already exist
              when image production begins,  then  it  will  get  created  and
              marked  for  Rock  Ridge  as  relocation  artefact.  At least on
              GNU/Linux it will not be displayed in mounted Rock Ridge images.
              The name must not  contain  a  '/'  character  after  its  first
              character and it must not be longer than 255 bytes.
              This option has no effect if option -D is present.

       -hide-rr-moved
              Alias of -rr_reloc_dir "/.rr_moved"

       --for_backup
              Enable all options which improve backup fidelity:
              --acl, --xattr-any, --md5, --hardlinks.
              If   you  later  restore  a  backup  with  xattr  from  non-user
              namespaces, then make sure that the target operating system  and
              filesystem  know  what  these attributes mean. Possibly you will
              need  administrator  privileges  to  record  or   restore   such
              attributes.  At  recording  time,  xorriso  will try to tolerate
              missing privileges and just record what is readable.
              Option  -xattr  after  option  -for_backup   excludes   non-user
              attributes from being recorded.

       --acl
              Enable  recording  and loading of ACLs from GNU/Linux or FreeBSD
              (see man getfacl, man acl).  They will not  be  in  effect  with
              mounted  ISO  images.  But  xorriso can restore them on the same
              systems when extracting files from the ISO image.

       --xattr
              Enable recording and loading of GNU/Linux  or  FreeBSD  extended
              attributes in user namespace (see man getfattr and man attr, man
              getextattr and man 9 extattr, respectively).  They will  not  be
              in  effect with mounted ISO images. But xorriso can restore them
              on the same systems when extracting files from the ISO image.

       --xattr-any
              Enable recording and loading of GNU/Linux  or  FreeBSD  extended
              attributes  in  all  namespaces.  This  might need administrator
              privileges, even if the owner of the disk file tries to read the
              attributes.

       --md5
              Enable  recording of MD5 checksums for the overall ISO image and
              for each single data file in the image. xorriso  can  check  the
              content  of  an  ISO  image  with  these sums and raise alert on
              mismatch.  See man xorriso, options  -check_media,  check_md5_r.
              xorriso can print recorded MD5 checksums. E.g. by:
               -find / -exec get_md5

       --hardlinks
              Enable  loading and recording of hardlink relations.  Search for
              families of iso_rr files which stem from  the  same  disk  file,
              have  identical content filtering and have identical properties.
              The members of each family get the same inode number in the  ISO
              image.
              Whether these numbers are respected at mount time depends on the
              operating system. xorriso  can  create  hardlink  families  when
              extracting files from the ISO image.

       --scdbackup_tag disk_path record_name
              Append a scdbackup checksum record to the image. This works only
              if the parameter next_writeable_address of option -C  is  0  and
              --md5  is  enabled.   If  disk_path is not an empty string, then
              append a scdbackup checksum record to  the  end  of  this  file.
              record_name is a word that gets part of tag and record.
              Program  scdbackup_verify will recognize and verify tag and file
              record.
              An empty record_name disables this feature.

       -J
              Enable the production of an  additional  Joliet  directory  tree
              along with the ISO 9660 Rock Ridge tree.

       -joliet
              Alias of -J.

       -joliet-long
              Allow  103  characters in Joliet file names rather than 64 as is
              prescribed by the specification. Allow Joliet paths longer  than
              the prescribed limit of 240 characters.
              Oversized  names  get  truncated. Without this option, oversized
              paths get excluded from the Joliet tree.

       -joliet-utf16
              Encode Joliet file names in UTF-16BE  rather  than  UCS-2.   The
              difference is with characters which are not present in UCS-2 and
              get encoded in UTF-16 by 2 words of 16  bit  each.   Both  words
              then stem from a reserved subset of UCS-2.

       -hfsplus
              Enable  the  production  of an additional HFS+ filesystem inside
              the ISO 9660 image and mark it  by  Apple  Partition  Map  (APM)
              entries in the System Area, the first 32 KiB of the image.
              This  may  collide  with options like -G or -isohybrid-mbr which
              submit user data for inclusion in the same address  range.   The
              first  8  bytes  of  the  System Area get overwritten by { 0x45,
              0x52, 0x08 0x00, 0xeb, 0x02, 0xff, 0xff } which can be  executed
              as x86 machine code without negative effects.  So if an MBR gets
              combined with this  feature,  then  its  first  8  bytes  should
              contain no essential commands.
              The  next blocks of 2 KiB in the System Area will be occupied by
              APM entries.  The first one covers the part  of  the  ISO  image
              before  the  HFS+  filesystem metadata. The second one marks the
              range from HFS+ metadata to the end of  file  content  data.  If
              more  ISO  image  data follow, then a third partition entry gets
              produced. Other features of xorriso might  cause  the  need  for
              more APM entries.
              Be  aware  that  HFS+ is case-insensitive although it can record
              file names with upper-case and  lower-case  letters.  Therefore,
              file  names  from  the  iso_rr name tree may collide in the HFS+
              name tree. In this case they get changed  by  adding  underscore
              characters  and counting numbers. In case of very long names, it
              might be necessary to map them to "MANGLED_...".
              WARNING:
              The HFS+ implementation in libisofs has a limit  of  125,829,120
              bytes  for the size of the overall directory tree. This suffices
              for about 300,000 files of normal name length. If the limit gets
              exceeded,  a FAILURE event will be issued and the ISO production
              will not happen.

       -hfsplus-serial-no
              Set a string of 16 digits "0" to "9" and  letters  "a"  to  "f",
              which  will  be used as unique serial number of an emerging HFS+
              filesystem.

       -hfsplus-block-size number
              Set the allocation block size to be  used  when  producing  HFS+
              filesystems.  Permissible  are 512, 2048, or 0.  The latter lets
              the program decide.

       -apm-block-size number
              Set the block size to be used when describing partitions  by  an
              Apple Partition Map. Permissible are 512, 2048, or 0. The latter
              lets the program decide.
              Note that size 512 is not compatible with production of GPT, and
              that  size  2048  will  not  be mountable -t hfsplus at least by
              older Linux kernels.

       -hfsplus-file-creator-type creator type iso_rr_path
              Set the HFS+ creator and  type  attributes  of  a  file  in  the
              emerging image.  These are two codes of 4 characters each.

       -hfs-bless-by blessing iso_rr_path
              Issue a HFS+ blessing. They are roles which can be attributed to
              up to four directories and a data file:
              "ppc_bootdir",  "intel_bootfile",  "show_folder",  "os9_folder",
              "osx_folder".
              They may be abbreviated as "p", "i", "s", "9", and "x".
              Each  such  role  can  be attributed to at most one file object.
              "intel_bootfile" is the one that would apply to a data file. All
              others  apply to directories.  No file object can bear more than
              one blessing.

       -hfs-bless disk_path
              Issue HFS+ blessing "ppc_bootdir" to the directory  which  stems
              from the directory disk_path in the local filesystem tree.
              This  works  only  if there is at least one data file underneath
              the directory.  disk_path can become  ambiguous  if  files  from
              different  local  filesystem  sub-trees  are  put  into the same
              sub-tree of the ISO image.  Consider to  use  -hfs-bless-by  "p"
              for unambiguous addressing via iso_rr_path.

       Settings for file hiding:

       -hide disk_path_pattern
              Make  files invisible in the directory tree of ISO 9660 and Rock
              Ridge,  if  their  disk_path  matches  the  given  shell  parser
              pattern.  The data content of such hidden files will be included
              in the resulting image, even if they  do  not  show  up  in  any
              directory.  But you will need own means to find nameless data in
              the image.
              This command does not apply to the boot catalog.

       -hide-list disk_path
              Perform -hide using each line out of file disk_path as  argument
              disk_path_pattern.

       -hide-joliet disk_path_pattern
              Like  option  -hide  but making files invisible in the directory
              tree of Joliet, if  their  disk_path  matches  the  given  shell
              parser pattern.

       -hide-joliet-list disk_path
              Perform  -hide-joliet  using  each line out of file disk_path as
              argument disk_path_pattern.

       -hide-hfsplus disk_path_pattern
              Like option -hide but making files invisible  in  the  directory
              tree  of HFS+, if their disk_path matches the given shell parser
              pattern.

       -hide-hfsplus-list disk_path
              Perform -hide-hfsplus using each line out of file  disk_path  as
              argument disk_path_pattern.

       ISO image ID strings:

       The  following  strings  and  file  addresses get stored in the Primary
       Volume Descriptor of the ISO9660 image. The file addresses are ISO 9660
       paths.  These  files should have iso_rr_paths which consist only of the
       characters [A-Z0-9_] and exactly one dot  which  separates  at  most  8
       characters from at most 3 characters.

       -V text
              Set the Volume Id of the ISO image.  xorriso accepts any text up
              to 32 characters, but according to rarely obeyed specs  stricter
              rules apply:
              Conformant   are   ASCII  characters  out  of  [A-Z0-9_].  Like:
              "IMAGE_23"
              Joliet allows 16 UCS-2 characters. Like: "Windows name"
              Be aware that the volume id might get used automatically as name
              of  the  mount  point when the medium is inserted into a playful
              computer system.

       -volid text
              Alias of -V.

       -volset text
              Set the Volume Set Id of the ISO image.  Permissible are  up  to
              128 characters.

       -P text
              Set  the  Publisher  Id  of the ISO image. This may identify the
              person or organisation who specified  what  shall  be  recorded.
              Permissible are up to 128 characters.

       -publisher text
              Alias of -P.

       -A text
              Set  the Application Id of the ISO image.  This may identify the
              specification of how the data are recorded.  Permissible are  up
              to 128 characters.
              The  special text "@xorriso@" gets converted to the id string of
              xorriso which is normally written as Preparer Id. It is a  wrong
              tradition to write the program id as Application Id.

       -appid text
              Alias of -A.

       -sysid text
              Set the System Id of the ISO image. This may identify the system
              which can recognize and act upon the content of the System  Area
              in image blocks 0 to 15.  Permissible are up to 32 characters.

       -p text
              Set  the  Preparer  Id  of  the ISO image. This may identify the
              person or other entity which controls  the  preparation  of  the
              data  which shall be recorded. Normally this should be the id of
              xorriso and not of the person or program which operates xorriso.
              Please   avoid   to  change  it.   Permissible  are  up  to  128
              characters.
              The special text "@xorriso@" gets converted to the id string  of
              xorriso which is default at program startup.

       -preparer text
              Alias of -p.

       -abstract iso_path
              Set  the  address  of  the  Abstract File of the ISO image. This
              should be the ISO 9660  path  of  a  file  in  the  image  which
              contains   an   abstract  statement  about  the  image  content.
              Permissible are up to 37 characters.

       -biblio iso_path
              Set the address of the Biblio File of the ISO image. This should
              be  the  ISO  9660  path  of  a file in the image which contains
              bibliographic records.  Permissible are up to 37 characters.

       -copyright iso_path
              Set the address of the Copyright File of  the  ISO  image.  This
              should  be  the  ISO  9660  path  of  a  file in the image which
              contains a  copyright  statement.   Permissible  are  up  to  37
              characters.

       --modification-date=YYYYMMDDhhmmsscc
              Set   a   timestring  that  overrides  ISO  image  creation  and
              modification  timestamps  literally.   It  must  consist  of  16
              decimal  digits  which  form YYYYMMDDhhmmsscc, with YYYY between
              1970 and 2999. Time zone is GMT.  It is supposed to  match  this
              GRUB line:
               search --fs-uuid --set YYYY-MM-DD-hh-mm-ss-cc
              E.g. 2010040711405800 is 7 Apr 2010 11:40:58 (+0 centiseconds).
              Among the influenced timestamps are: isohybrid MBR id, El Torito
              boot catalog file, HFS+ superblock.

       --application_use character|0xXY|disk_path
              Specify the content of the Application Use field which can  take
              at most 512 bytes.
              If  the  parameter  of  this command is empty, then the field is
              filled with 512 0-bytes. If it is a single  character,  then  it
              gets  repeated  512 times.  If it begins by "0x" followed by two
              hex digits [0-9a-fA-F], then the digits are read as  byte  value
              which gets repeated 512 times.
              Any  other  parameter  text  is used as disk_path to open a data
              file and to read up to 512 bytes from it. If the file is smaller
              than 512 bytes, then the remaining bytes in the field get set to
              binary 0.

       El Torito Bootable ISO images:

       The precondition for a bootable ISO image is to have in the  ISO  image
       the  files  of  a  boot  loader.  The  boot facilities of computers get
       directed to such files, which usually  execute  further  program  files
       from  the ISO image.  xorrisofs can produce several kinds of boot block
       or boot record, which become part of the ISO image, and get interpreted
       by the according boot facility.

       An  El  Torito  boot record points the bootstrapping facility to a boot
       catalog with one or more boot images, which are  binary  program  files
       stored in the ISO image.  The content of the boot image files is not in
       the scope of El Torito.
       xorriso composes the boot catalog according to  the  boot  image  files
       given  and  structured  by  options  -b,  -e,  -eltorito-alt-boot,  and
       --efi-boot. Often it contains only one entry.
       Normally the boot images are data files inside the ISO  filesystem.  By
       special  path  "--interval:appended_partition_NNN:all::" it is possible
       to refer to an appended partition. The number NNN gives  the  partition
       number as used with the corresponding option -append_partition.  E.g.:
         -append_partition 2 0xef /tmp/efi.img
         -e --interval:appended_partition_2:all::
       El  Torito  gets  interpreted by boot facilities PC-BIOS and EFI.  Most
       bootable GNU/Linux CDs are equipped with ISOLINUX or GRUB  boot  images
       for PC-BIOS.
       xorrisofs  supports  the  example options out of the ISOLINUX wiki, the
       options used in GRUB script  grub-mkrescue,  and  the  example  in  the
       FreeBSD AvgLiveCD wiki.

       For  CD booting via boot facilities other than PC-BIOS and EFI, and for
       booting from USB sticks or hard disks, see the next section  about  the
       System Area.

       -b iso_rr_path
              Specify  the  boot  image  file  which shall be mentioned in the
              current entry of the El Torito boot catalog. It will  be  marked
              as suitable for PC-BIOS.
              With  boot  images  from ISOLINUX and GRUB this option should be
              accompanied by options -c , -no-emul-boot , -boot-load-size 4  ,
              -boot-info-table.

       -eltorito-boot iso_rr_path
              Alias of -b.

       -eltorito-alt-boot
              Finalize  the  current  El Torito boot catalog entry and begin a
              new one.  A boot image file and all its necessary options  shall
              be  specified  before option -eltorito-alt-boot.  All further El
              Torito boot options apply to the new catalog  entry.  Up  to  32
              catalog entries are possible.

       -e iso_rr_path
              Specify  the  boot  image  file  which shall be mentioned in the
              current entry of the El Torito boot catalog. It will  be  marked
              as suitable for EFI.
              Option  -e  should  be  followed  by option -no-emul-boot and no
              other El Torito options before an eventual -eltorito-alt-boot.

       --efi-boot iso_rr_path
              Perform   -eltorito-alt-boot,   option   -e   with   the   given
              iso_rr_path,  -no-emul-boot,  and again -eltorito-alt-boot. This
              gesture is used  for  achieving  EFI-bootability  of  the  GRUB2
              rescue CD.

       -eltorito-platform "x86"|"PPC"|"Mac"|"efi"|0xnn|nnn
              Set   the   Platform  Id  number  for  the  next  option  -b  or
              -eltorito-boot.  The number may be chosen by a platform name  or
              by  a number between 0 and 255 (0x00 and 0xFF). "x86" = 0 is for
              PC-BIOS, "PPC" = 1 for some PowerPC systems, "Mac" = 2 for  some
              MacIntosh  systems,  "efi" = 0xEF for EFI on modern PCs with x86
              compatible CPUs or others.
              If  the  new  platform  id  differs  from  the   previous   one,
              -eltorito-alt-boot gets performed.

       -boot-load-size number|"full"
              Set the number of 512-byte blocks to be loaded at boot time from
              the boot image in the current catalog entry.
              Non-emulating BIOS bootimages usually need a  load  size  of  4.
              Nevertheless  the  default setting of mkisofs is to use the full
              size of the boot image rounded up to a multiple  of  4  512-byte
              blocks.  This  default  may  be  explicitly enforced by the word
              "full" instead of a number.
              EFI boot images usually get set the number of blocks occupied by
              the boot image file.
              El Torito cannot represent load sizes higher than 65535.

       -hard-disk-boot
              Mark  the  boot  image  in the current catalog entry as emulated
              hard disk.  (Not suitable for any known boot loader.)

       -no-emul-boot
              Mark the  boot  image  in  the  current  catalog  entry  as  not
              emulating  floppy  or  hard  disk.  (This is to be used with all
              known boot loaders.)
              If neither -hard-disk-boot nor -no-emul-boot is given, then  the
              boot  image will be marked as emulating a floppy.  (Not suitable
              for any known boot loader.)

       -eltorito-id text|56_hexdigits
              Define the ID string of the boot catalog section where the  boot
              image  will  be  listed.  If the value consists of 56 characters
              [0-9A-Fa-f] then it is converted into 28 bytes, else  the  first
              28  characters become the ID string.  The ID string of the first
              boot image becomes the overall catalog ID.  It is limited to  24
              characters. Other id_strings become section IDs.

       -eltorito-selcrit hexdigits
              Define the Selection Criteria of the boot image.  Up to 20 bytes
              get read  from  the  given  characters  [0-9A-Fa-f].   They  get
              attributed to the boot image entry in the catalog.

       -boot-info-table
              Overwrite  bytes  8  to  63  in  the  current  boot  image.  The
              information will be supplied by xorriso in the course  of  image
              production:  Block  address  of  the  Primary Volume Descriptor,
              block address of the boot image file, size  of  the  boot  image
              file.

       --grub2-boot-info
              Overwrite  bytes  2548  to 2555 in the current boot image by the
              address of that boot image.  The address is written  as  64  bit
              little-endian  number.  It  is the 2KB block address of the boot
              image content, multiplied by 4, and then incremented by 5.

       -c iso_rr_path
              Set the address of the El Torito boot catalog  file  within  the
              image.   This  file  address  is not significant for the booting
              PC-BIOS or EFI, but it may later be read by  other  programs  in
              order to learn about the available boot images.

       -eltorito-catalog iso_rr_path
              Alias of -c.

       --boot-catalog-hide
              Prevent the El Torito boot catalog from appearing as file in the
              directory trees of the image.

       System Area, MBR, GPT, APM, other boot blocks:

       The first 16 blocks of an  ISO  image  are  the  System  Area.   It  is
       reserved  for  system  dependent  boot  software.  This may be the boot
       facilities and partition tables of various hardware architectures.
       A MBR (Master Boot Record) contains boot code and  a  partition  table.
       It  is read by PC-BIOS when booting from USB stick or hard disk, and by
       PowerPC CHRP or PReP when booting.  An MBR  partition  with  type  0xee
       indicates the presence of GPT.
       A GPT (GUID Partition Table) marks partitions in a more modern way.  It
       is read by EFI when booting from USB stick or hard  disk,  and  may  be
       used for finding and mounting a HFS+ partition inside the ISO image.
       An  APM  (Apple Partition Map) marks the HFS+ partition.  It is read by
       Macs for booting and for mounting.
       MBR, GPT and APM are combinable. APM occupies the first 8 bytes of  MBR
       boot code. All three do not hamper El Torito booting from CDROM.
       xorrisofs supports further boot facilities: MIPS Big Endian (SGI), MIPS
       Little Endian (DEC), SUN SPARC, HP-PA, DEC Alpha.  Those  are  mutually
       not combinable and also not combinable with MBR, GPT, or APM.

       Several  of  the  following options expect disk paths as input but also
       accept description strings for the libisofs interval reader,  which  is
       able  to cut out data from disk files or -indev and to zeroize parts of
       the   content:   -G,   -generic-boot,   --embedded-boot,   --grub2-mbr,
       -isohybrid-mbr,   -efi-boot-part,   -prep-boot-part,  -B,  -sparc-boot,
       -append_partition.
       The description string consists of the following components,  separated
       by colon ':'
         "--interval:"Flags":"Interval":"Zeroizers":"Source
       The  component  "--interval"  states that this is not a plain disk path
       but rather a interval reader description string.
       The component Flags modifies the further interpretation:
       "local_fs" demands to read from a file depicted by the path in Source.
       "imported_iso" demands to read from the  -indev.  This  works  only  if
       -outdev is not the same as -indev. The Source component is ignored.
       "appended_partition_NNN"  with  a  decimal  number  NNN  works only for
       options which announce El Torito boot image paths: -b, -e,  --efi-boot.
       The  number  gives  the partition number as used with the corresponding
       option -append_partition.
       The component Interval consists of two byte address  numbers  separated
       by a "-" character. E.g. "0-429" means to read bytes 0 to 429.
       The  component  Zeroizers  consists  of  zero  or  more comma separated
       strings.  They define which part of the  read  data  to  zeroize.  Byte
       number  0  means  the  byte read from the Interval start address.  Each
       string may be one of:
       "zero_mbrpt" demands to zeroize the MBR partition table  if  bytes  510
       and 511 bear the MBR signature 0x55 0xaa.
       "zero_gpt"  demands  to check for a GPT header in bytes 512 to 1023, to
       zeroize it and its partition table blocks.
       "zero_apm" demands to check for an APM  block  0  and  to  zeroize  its
       partition table blocks.
       Start_byte"-"End_byte  demands  to  zeroize the read-in bytes beginning
       with number Start_byte and ending after End_byte.
       The component Source is the file path with flag "local_fs", and ignored
       with flag "imported_iso".
       Byte  numbers  may  be  scaled by a suffix out of {k,m,g,t,s,d} meaning
       multiplication by {1024, 1024k, 1024m,  1024g,  2048,  512}.  A  scaled
       value end number depicts the last byte of the scaled range.
       E.g. "0d-0d" is "0-511".
       Examples:
         "local_fs:0-32767:zero_mbrpt,zero_gpt,440-443:/tmp/template.iso"
         "imported_iso:45056d-47103d::"

       -G disk_path
              Copy  at  most  32768 bytes from the given disk file to the very
              start of the ISO image.
              Other than a El Torito boot image, the file disk_path needs  not
              to be added to the ISO image. It will not show up as file in the
              directory trees.
              In multi-session situations, the special disk_path "."  prevents
              reading  of  a disk file but nevertheless causes the adjustments
              in the existing MBR, which were ordered by other options.

       -generic-boot disk_path
              Alias of -G.

       --embedded-boot disk_path
              Alias of -G.

       --grub2-mbr disk_path
              Install disk_path in the System Area  and  treat  it  as  modern
              GRUB2 MBR.  The content start address of the first boot image is
              converted to a count of 512 byte blocks, and an offset of  4  is
              added.   The result is written as 64 bit little-endian number to
              byte address 0x1b0.

       -isohybrid-mbr disk_path
              Install disk_path as ISOLINUX isohybrid MBR which makes the boot
              image given by option -b bootable from USB sticks and hard disks
              via PC-BIOS.  This preparation  is  normally  done  by  ISOLINUX
              program isohybrid on the already produced ISO image.
              The  disk  path  should  lead  to  one  of  the  Syslinux  files
              isohdp[fp]x*.bin .  The MBR gets patched according to  isohybrid
              needs. The first partition describes the range of the ISO image.
              Its start is at block 0 by default, but may be set  to  64  disk
              blocks by option -partition_offset 16.
              For the meaning of special disk_path "." see option -G.

       -isohybrid-gpt-basdat
              Mark the current El Torito boot image (see options -b and -e) in
              an actually invalid GPT as partition of type  Basic  Data.  This
              works  only  with  -isohybrid-mbr and has the same impact on the
              system area as  -efi-boot-part.   It  cannot  be  combined  with
              -efi-boot-part or -hfsplus.
              The  first  three  boot images which are marked by GPT will also
              show up as partition entries in MBR. The MBR partition  of  type
              0xEF  is  what actually is used by EFI firmware for booting from
              USB stick.  The MBR partition for PC-BIOS gets type 0x00  rather
              than  0x17  in this case.  Often the further MBR entries are the
              ones which actually get used by EFI.

       -isohybrid-gpt-hfsplus
              Mark the current El Torito boot image (see options -b and -e) in
              GPT as partition of type HFS+.  Impact and restrictions are like
              with -isohybrid-gpt-basdat.

       -isohybrid-apm-hfsplus
              Mark the current El Torito boot image (see options -b and -e) in
              Apple  Partition  Map as partition of type HFS+. This works only
              with -isohybrid-mbr and has a similar impact on the system  area
              as  -hfsplus.  It  cannot  be  combined  with  -efi-boot-part or
              -hfsplus.
              The ISOLINUX isohybrid MBR file must begin by a known pattern of
              32  bytes of x86 machine code which essentially does nothing. It
              will get overwritten by 32 bytes of APM header mock-up.

       -part_like_isohybrid
              Control whether  -isohybrid-gpt-basdat,  -isohybrid-gpt-hfsplus,
              and  -isohybrid-apm-hfsplus  apply even if not -isohybrid-mbr is
              present.  No MBR partition of type 0xee  emerges,  even  if  GPT
              gets  produced.  Gaps between GPT and APM partitions will not be
              filled by more partitions.  Appended partitions get mentioned in
              APM if other APM partitions emerge.

       -iso_mbr_part_type "default"|number|type_guid
              Set  the  partition  type  of  the  MBR  or  GPT partition which
              represents the ISO or at least protects it.
              Number may be 0x00 to 0xff. The text  "default"  re-enables  the
              default  types  of  the  various  occasions to create an ISO MBR
              partition.  This is without effect if no such partition  emerges
              by  other  settings  or  if  the  partition  type  is prescribed
              mandatorily like 0xee for GPT protective MBR or 0x96 for CHRP.
              If instead a type_guid is given by a 32-digit  hex  string  like
              a2a0d0ebe5b9334487c068b6b72699c7  or  by  a structured text like
              EBD0A0A2-B9E5-4433-87C0-68B6B72699C7, then it will  be  used  as
              partition  type  if  the  ISO filesystem appears as partition in
              GPT.   In  MBR,  C12A7328-F81F-11D2-BA4B-00A0C93EC93B  will   be
              mapped to 0xef.  Any other GUID will be mapped to 0x83.

       --protective-msdos-label
              Patch  the  System Area by a simple PC-DOS partition table where
              partition 1 claims the range of the ISO  image  but  leaves  the
              first  block  unclaimed.   This  is  mutally exclusive to option
              -isohybrid-mbr.

       --mbr-force-bootable
              Enforce an MBR partition with "bootable/active" flag if  options
              like  --protective-msdos-label  or --grub2-mbr are given.  These
              options normally cause the flag to be set if  there  is  an  MBR
              partition of type other than 0xee or 0xef.  If no such partition
              exists, then no bootflag  is  set,  unless  --mbr-force-bootable
              forces  creation  of a dummy partition of type 0x00 which covers
              only the first block of the ISO image.
              If no bootable MBR is indicated by other options and a partition
              gets  created  by  -append_partition,  then --mbr-force-bootable
              causes   a   bootflag   like   it    would    do    with    e.g.
              --protective-msdos-label.

       -partition_offset 2kb_block_adr
              Cause  a  partition table with a single partition that begins at
              the given block address. This is counted in  2048  byte  blocks,
              not in 512 byte blocks. If the block address is non-zero then it
              must be at least 16. Values larger than 16 are hardly of use.  A
              non-zero partition offset causes two superblocks to be generated
              and two sets of directory trees. The  image  is  then  mountable
              from its absolute start as well as from the partition start.
              The  offset  value  of  an  ISO  image gets preserved when a new
              session is added to a loaded image.  So the value  defined  here
              is only in effect if a new ISO image gets written.

       -partition_hd_cyl number
              Set  the  number  of  heads  per  cylinder for the MBR partition
              table.  0 chooses a default value. Maximum is 255.

       -partition_sec_hd number
              Set the number of sectors per head for the MBR partition  table.
              0 chooses a default value. Maximum is 63.
              The  product  partition_sec_hd  *  partition_hd_cyl * 512 is the
              cylinder size.  It should be divisible by 2048 in order to  make
              exact   alignment   possible.    With  appended  partitions  and
              -appended_part_as_gpt there  is  no  limit  for  the  number  of
              cylinders.  Else  there  may  be  at  most 1024 of them.  If the
              cylinder size is  too  small  to  stay  below  the  limit,  then
              appropriate   values   of   partition_hd_cyl   are  chosen  with
              partition_sec_hd  32  or  63.  If  the  image  is  larger   than
              8,422,686,720  bytes,  then the cylinder size constraints cannot
              be fulfilled for MBR.  They seem not  overly  important  anyway.
              Flat block addresses in partition tables are good for 1 TiB.

       -partition_cyl_align mode
              Control  image size alignment to an integer number of cylinders.
              It is prescribed by isohybrid  specs  and  it  seems  to  please
              program fdisk.  Cylinder size must be divisible by 2048.  Images
              larger  than  8,323,596,288  bytes  cannot  be  aligned  in  MBR
              partition table.
              Mode  "auto"  is  default.  Alignment by padding happens only if
              option -isohybrid-mbr is given.
              Mode   "on"   causes   alignment   by   padding   with    option
              --protective-msdos-label  too.  Mode "all" is like "on" but also
              pads up partitions from -append_partition to an aligned size.
              Mode "off" disables alignment unconditionally.

       -append_partition partition_number type_code disk_path
              Cause a prepared filesystem image to  be  appended  to  the  ISO
              image  and  to be described by a partition table entry in a boot
              block at the start of the  emerging  ISO  image.  The  partition
              entry will bear the size of the submitted file rounded up to the
              next multiple of 2048 bytes or  to  the  next  multiple  of  the
              cylinder size.
              Beware  of subsequent multi-session runs. The appended partition
              will get overwritten.
              partition_number may be 1 to 4. Number 1 will put the whole  ISO
              image  into  the unclaimed space before partition 1. So together
              with most xorriso MBR or GPT features, number  2  would  be  the
              most natural choice.
              The type_code may be "FAT12", "FAT16", "Linux", or a hexadecimal
              number between 0x00 and 0xff. Not all those numbers  will  yield
              usable  results.  For  a  list  of codes search the Internet for
              "Partition Types" or run fdisk command "L".   If  the  partition
              appears  in  GPT then type_code 0xef is mapped to the EFI System
              Partition Type GUID. All others get mapped to  Basic  Data  Type
              GUID.
              type_code  may  also  be  a  type  GUID as plain hex string like
              a2a0d0ebe5b9334487c068b6b72699c7  or  as  structured  text  like
              EBD0A0A2-B9E5-4433-87C0-68B6B72699C7.  It  will  be  used if the
              partition     is     mentioned     in     GPT.      In      MBR,
              C12A7328-F81F-11D2-BA4B-00A0C93EC93B will be mapped to 0xef. Any
              other   GUID   will   be    mapped    to    0x83.     In    APM,
              48465300-0000-11AA-AA11-00306543ECAC will be mapped to partition
              type "Apple_HFS", any other to "Data".
              If some other command causes the production  of  GPT,  then  the
              appended  partitions  will  be  mentioned there too, even if not
              -appended_part_as_gpt is given.

       -appended_part_as_gpt
              Marks partitions from -append_partition in GPT  rather  than  in
              MBR.  In this case the MBR shows a single partition of type 0xee
              which covers the whole output data.
              By default, appended partitions get marked in GPT only if GPT is
              produced because of other options.

       -appended_part_as_apm
              Marks  partitions from -append_partition in Apple Partition Map,
              too.
              By default, appended partitions get marked in APM only if APM is
              produced  because  of  other options and -part_like_isohybrid is
              enabled.

       -efi-boot-part disk_path
              Copy a file from disk into the emerging ISO image and mark it by
              a  GPT  entry  as  EFI  System  Partition.  EFI boot firmware is
              supposed to use a FAT filesystem image in such a  partition  for
              booting from USB stick or hard disk.
              Instead  of a disk_path, the word --efi-boot-image may be given.
              It exposes in GPT the content of the first El  Torito  EFI  boot
              image as EFI system partition. EFI boot images are introduced by
              options -e or --efi-boot.  The affected EFI  boot  image  cannot
              show up in HFS+ because it is stored outside the HFS+ partition.

       --gpt_disk_guid value
              Control  whether  an emerging GPT shall get a randomly generated
              disk GUID or whether the GUID is supplied by  the  user.   Value
              "random"  is  default.  Value "modification-date" produces a low
              quality GUID from the value set by option --modification-date=.
              A string of 32 hex digits, or a RFC 4122 compliant  GUID  string
              may  be  used to set the disk GUID directly. UEFI prescribes the
              first  three  components  of  a  RFC  4122  GUID  string  to  be
              byte-swapped in the binary representation:
              E.g. --gpt_disk_guid 2303cd2a-73c7-424a-a298-25632da7f446 equals
              --gpt_disk_guid 2acd0323c7734a42a29825632da7f446
              The partition GUIDs get generated by minimally varying the  disk
              GUID.

       -chrp-boot-part
              Mark  the  block  range  of  the whole emerging ISO image as MBR
              partition of type 0x96. This is not compatible  with  any  other
              feature  that  produces  MBR  partition  entries.  It  makes GPT
              unrecognizable.
              CHRP is often used in conjunction with HFS. It is not yet tested
              whether  HFS+  filesystems  produced  with option -hfsplus would
              boot on any CHRP capable machine which does not  boot  pure  ISO
              9660 as well.

       -chrp-boot
              Alias of -chrp-boot-part.

       -prep-boot-part disk_path
              Copy a file from disk into the emerging ISO image and mark it by
              a MBR partition entry  of  type  0x41.  PReP  boot  firmware  is
              supposed  to  read  the  content  of the partition as single ELF
              executable file.  This  option  is  compatible  with  other  MBR
              partitions and with GPT.

       -mips-boot iso_rr_path
              Declare  a  data  file in the image to be a MIPS Big Endian boot
              file and cause production of a MIPS Big  Endian  Volume  Header.
              This  is mutually exclusive with production of other boot blocks
              like MBR.  It will overwrite the first 512  bytes  of  any  data
              provided by -G.  Up to 15 boot files can be declared by multiple
              -mips-boot options.

       -mipsel-boot iso_rr_path
              Declare a data file in the image to be the  MIPS  Little  Endian
              boot  file.  This  is mutually exclusive with other boot blocks.
              It will overwrite the first 512 bytes of any  data  provided  by
              -G.  Only a single boot file can be declared by -mipsel-boot.

       -B disk_path[,disk_path ...]
              Cause one or more data files on disk to be written after the end
              of the ISO image. A SUN Disk Label  will  be  written  into  the
              first  512  bytes  of  the  ISO  image which lists this image as
              partition 1 and the given disk_paths as partition 2 up to 8.
              The disk files should contain suitable boot images for SUN SPARC
              systems.
              The  pseudo  disk_path  "..."  causes  that  all empty partition
              entries become copies of the last non-empty entry. If  no  other
              disk_path is given before "..." then all partitions describe the
              ISO image. In this case, the boot loader code has to be imported
              by option -G.

       -sparc-boot disk_path[,disk_path ...]
              Alias of -B.

       -sparc-label text
              Set the ASCII label text of a SUN Disk Label.

       --grub2-sparc-core iso_rr_path
              Cause the content address and size of the given data file in the
              image to be written after the SUN Disk Label. Both  numbers  are
              counted  in  bytes.  The address is written as 64 bit big-endian
              number to byte 0x228.  The size is written as 32 bit  big-endian
              number to byte 0x230.

       -hppa-cmdline text
              Set  the  PALO command line for HP-PA. Up to 1023 characters are
              permitted by default. With -hppa-hdrversion 4 the limit is 127.
              Note that the first five -hppa options are mandatory, if any  of
              the  -hppa  options  is  given.  Only option -hppa-hdrversion is
              allowed to be missing.

       -hppa-bootloader iso_rr_path
              Designate the given path as HP-PA bootloader file.

       -hppa-kernel-32 iso_rr_path
              Designate the given path as HP-PA 32 bit kernel file.

       -hppa-kernel-64 iso_rr_path
              Designate the given path as HP-PA 64 bit kernel file.

       -hppa-ramdisk iso_rr_path
              Designate the given path as HP-PA RAM disk file.

       -hppa-hdrversion number
              Choose between PALO header version 5 (default)  and  version  4.
              For   the   appropriate   value   see   in   PALO  source  code:
              PALOHDRVERSION.

       -alpha-boot iso_rr_path
              Declare a data file in  the  image  to  be  the  DEC  Alpha  SRM
              Secondary Bootstrap Loader and cause production of a boot sector
              which points to it.  This is mutually exclusive with  production
              of other boot blocks like MBR.

       Character sets:

       Character  sets  should not matter as long as only english alphanumeric
       characters are used for file names  or  as  long  as  all  writers  and
       readers  of  the  medium  use  the  same  character set.  Outside these
       constraints it may be necessary to let xorriso convert byte codes.
       A conversion from input character set to the output  character  set  is
       performed  when  an  ISO  image  gets  written.   Vice versa there is a
       conversion from output character set to the input character set when an
       ISO   image   gets   loaded.   The  sets  can  be  defined  by  options
       -input-charset and -output-charset, if needed.

       -input-charset character_set_name
              Set the character set from which to convert disk file names when
              inserting them into the ISO image.

       -output-charset character_set_name
              Set the character set from which to convert  names of loaded ISO
              images and to which to convert names when writing ISO images.

       Jigdo Template Extraction:

       From man genisoimage: "Jigdo is a tool to help in the  distribution  of
       large  files  like CD and DVD images; see http://atterer.net/jigdo/ for
       more details. Debian CDs and DVD ISO images are published on the web in
       jigdo format to allow end users to download them more efficiently."
       If  the  use  of  libjte  was  enabled at compile time of xorriso, then
       xorrisofs can produce a .jigdo and a .template  file  together  with  a
       single-session  ISO  image.  If  not,  then  Jigdo options will cause a
       FAILURE event, which normally leads to program abort.
       One may determine the ability for Jigdo by:
         $ xorrisofs -version 2>&1 | grep '^libjte' && echo YES

       The .jigdo file contains checksums and symbolic  file  addresses.   The
       .template  file  contains  the compressed ISO image with reference tags
       instead of the content bytes of the listed files.
       Input for this process are the normal arguments for a xorrisofs session
       with  no image loaded, and a checksum file which lists those data files
       which may be listed in the .jigdo file and externally referenced in the
       .template  file.   Each  designated file is represented in the checksum
       file by a single text line:
       Checksum as hex digits, 2 blanks, size as 12 decimal digits or  blanks,
       2 blanks, symbolic file address
       The  kind  of  checksum  is  chosen by -jigdo "checksum_algorithm" with
       values "md5" (32 hex digits) or "sha256" (64 hex digits).  It will also
       be used for the file address lines in the .jigdo file.
        The default is "md5".
       The  file address in a checksum file line has to bear the same basename
       as the disk_path of the file which it shall match. The  directory  path
       of  the  file  address  is  decisive  for To=From mapping, not for file
       recognition.  After To=From mapping, the file address gets written into
       the  .jigdo file. Jigdo restore tools will convert these addresses into
       really reachable data source addresses from which they can read.
       If the list of jigdo parameters is not  empty,  then  padding  will  be
       counted as part of the ISO image.

       -jigdo-checksum-algorithm "md5"|"sha256"
              Set the checksum algorithm which shall be used for the data file
              entries in the .jigdo file and is expected in the checksum file.
              Default is "md5".

       -jigdo-jigdo disk_path
              Set  the  disk_path  for  the .jigdo file with the checksums and
              download addresses for filling the holes in .template.

       -jigdo-template disk_path
              Set the disk_path for the .template  file  with  the  holed  and
              compressed ISO image copy.

       -jigdo-min-file-size size
              Set  the minimum size for a data file to be listed in the .jigdo
              file and being a hole in the .template  file.   size  may  be  a
              plain  number  counting  bytes, or a number with appended letter
              "k", "m", "g" to count KiB (1024 bytes), MiB (1024 KiB), or  GiB
              (1024 MiB).

       -jigdo-force-checksum disk_path_pattern
              adds  a  regular expression pattern which will get compared with
              the absolute disk_path of any data file that was  not  found  in
              the  checksum  file.   A  match  causes  a  MISHAP  event, which
              normally does not abort the program run  but  finally  causes  a
              non-zero exit value of the program.

       -jigdo-force-md5 disk_path_pattern
              Outdated alias of -jigdo-force-checksum.

       -jigdo-exclude disk_path_pattern
              Add  a  regular  expression pattern which will get compared with
              the absolute disk_path of any data file. A match causes the file
              to stay in .template in any case.

       -jigdo-map To=From
              Add a string pair of the form To=From to the parameter list.  If
              a data file gets listed in the .jigdo file, then it is  referred
              by  the  file  address  from its line in the checksum file. This
              file address gets  checked  whether  it  begins  with  the  From
              string.  If  so,  then  this  string  will be replaced by the To
              string and a ':' character, before it goes into the .jigdo file.
              The From string should end by a '/' character.

       -checksum-list disk_path
              Set  the  disk_path  where  to  find the checksum file file with
              symbolic   file   addresses   and   checksums    according    to
              -jigdo-checksum-algorithm.

       -md5-list disk_path
              Outdated alias of -checksum-list.

       -jigdo-template-compress "gzip"|"bzip2"
              Choose  one  of  "bzip2"  or  "gzip"  for the compression of the
              template file. The jigdo file is put out uncompressed.

       -checksum_algorithm_iso list_of_names
              Choose one or more of "md5", "sha1", "sha256", "sha512" for  the
              auxiliary  "#  Image  Hex"  checksums  in  the  .jigdo file. The
              list_of_names may e.g. look like "md5,sha1,sha512". Value  "all"
              chooses  all  available  algorithms.  Note that MD5 stays always
              enabled.

       -checksum_algorithm_template list_of_names
              Choose the algorithms for the "# Template Hex" checksums in  the
              .jigdo  file.   The rules for list_of_names are the same as with
              -checksum_algorithm_iso.

       Miscellaneous options:

       -print-size
              Print to stdandard output the foreseeable number  of  2048  byte
              blocks in the emerging ISO image. Do not produce this image.
              The result depends on several settings.
              If  option  --emul-toc  is given, then padding (see -pad) is not
              counted as part of the image  size.  In  this  case  either  use
              -no-pad or add 150 (= 300 KiB) to the resulting number.
              If  mkisofs  emulation  ends  after option -print-size, then the
              properties of the most recently specified boot image file cannot
              be edited by subsequent xorriso commands.

       --no_rc
              Only  if used as first argument this option prevents reading and
              interpretation of startup files. See section FILES below.

       -help
              List supported options to stderr. Original mkisofs options  bear
              their original mkisofs description texts.

       -quiet
              Suppress  most  messages  of the program run, except those which
              indicate problems or errors.

       -gui
              Increase the frequency of pacifier messages while writing an ISO
              image.

       -log-file disk_path
              Truncate  file  disk_path  to  0  size  and  redirect  to it all
              messages which would normally appear on stderr.  -log-file  with
              empty text as disk_path re-enables output to stderr.

       -v
              Enable the output of informational program messages.

       -verbose
              Alias of -v.

       -version
              Print to standard output a text that begins with
               "mkisofs 2.01-Emulation Copyright (C)"
              and to standard error the version information of xorriso.

EXAMPLES
   Overview of examples:
       A simple image production run
       Set ISO image paths by -graft-points
       Perform multi-session runs
       Let xorrisofs work underneath growisofs
       Incremental backup of a few directory trees
       Incremental backup with accumulated trees
       Create bootable images for PC-BIOS and EFI

   A simple image production run
       A  prepared  file tree in directory ./for_iso gets copied into the root
       directory of the ISO image. File permissions get set to  read-only  for
       everybody.   Joliet  attributes  for  Microsoft systems get added.  The
       resulting image gets written as data file ./image.iso on disk.
         $ xorrisofs -r -J -o ./image.iso ./for_iso

   Set ISO image paths by -graft-points
       Without option -graft-points each given disk file is  copied  into  the
       root  directory  of the ISO image, maintaining its name. If a directory
       is given, then its files and sub-directories are copied into  the  root
       directory, maintaining their names.
         $ xorrisofs ... /home/me/datafile /tmp/directory
       yields in the ISO image root directory:
         /datafile
         /file_1_from_directory
         ...
         /file_N_from_directory

       With  option  -graft-points it is possible to put files and directories
       to arbitrary paths in the ISO image.
         $ xorrisofs ... -graft-points /home/me/datafile /dir=/tmp/directory
       yields in the ISO image root directory:
         /datafile
         /dir
       Eventually needed parent directories  in  the  image  will  be  created
       automatically:
         /datafiles/file1=/home/me/datafile
       yields in the ISO image:
         /datafiles/file1
       The  attributes  of  directory  /datafiles  get copied from /home/me on
       disk.

       Normally one should avoid = and \ characters  in  the  ISO  part  of  a
       pathspec.  But if it must be, one may escape them:
         /with_\=_and_\\/file=/tmp/directory/file
       yields in the ISO image:
         /with_=_and_\/file

   Perform multi-session runs
       This  example  works  for  multi-session media only: CD-R[W], DVD-R[W],
       DVD+R, BD-R.  Add cdrskin option --grow_overwriteable_iso  to  all  -as
       cdrecord   runs   in   order   to  enable  multi-session  emulation  on
       overwritable media.
       The first session is written like this:
         $ xorrisofs -graft-points \
                     /tree1=prepared_for_iso/tree1 \
           | xorriso -as cdrecord -v dev=/dev/sr0 blank=fast -multi -eject -
       Follow-up sessions are written like this (the run of dd is only to give
       demons a chance to spoil it):
         $ m=$(xorriso -as cdrecord dev=/dev/sr0 -msinfo)
         $ dd if=/dev/sr0 count=1 >/dev/null 2>&1
         $ xorrisofs -M /dev/sr0 -C $m -graft-points \
                     /tree2=prepared_for_iso/tree2 \
           | xorriso -as cdrecord -v dev=/dev/sr0 -waiti -multi -eject -
       Always eject the drive tray between sessions.
       The  run  of  xorriso -as mkisofs will read old sessions via the CD-ROM
       driver of /dev/sr0. This driver might  not  be  aware  of  the  changed
       content  as  long  as  the medium is not loaded again. In this case the
       previous session would not be properly assessed by xorriso and the  new
       session would contain only the newly added files.
       Some  systems  have not enough patience with automatic tray loading and
       some demons may interfere with a first CD-ROM driver read attempt  from
       a freshly loaded medium.
       When  loading  the  tray  manually, wait 10 seconds after the drive has
       stopped blinking.
       A safe automatic way seems to be a separate run of xorriso for  loading
       the  tray  with  proper waiting, and a subsequent run of dd which shall
       offer itself to any problems caused by  demons  assessing  the  changed
       drive  status.   If  this  does  not  help,  insert a run of "sleep 10"
       between xorriso and dd.

   Let xorrisofs work underneath growisofs
       growisofs expects an ISO formatter program which understands options -C
       and -M. A variable is defined to override the hardcoded default name.
         $ export MKISOFS="xorrisofs"
         $ growisofs -Z /dev/dvd /some/files
         $ growisofs -M /dev/dvd /more/files
       If  no  "xorrisofs"  is available on your system, then you will have to
       create a link pointing to the xorriso binary and tell growisofs to  use
       it. E.g. by:
         $ ln -s $(which xorriso) "$HOME/xorrisofs"
         $ export MKISOFS="$HOME/xorrisofs"
       One  may  quit  mkisofs  emulation by argument "--" and make use of all
       xorriso commands. growisofs dislikes options which start with "-o"  but
       -outdev must be set to "-".  So use "outdev" instead:
         $ growisofs -Z /dev/dvd --for_backup -- \
                     outdev - -update_r /my/files /files
         $ growisofs -M /dev/dvd --for_backup -- \
                     outdev - -update_r /my/files /files
       Note  that --for_backup is given in the mkisofs emulation.  To preserve
       the recorded extra  data  it  must  already  be  in  effect,  when  the
       emulation loads the image.

   Incremental backup of a few directory trees
       This    changes    the   directory   trees   /open_source_project   and
       /personal_mail in the ISO image so that they  become  exact  copies  of
       their  disk counterparts.  ISO file objects get created, deleted or get
       their attributes adjusted accordingly.
       ACL, xattr, hard links and MD5  checksums  will  be  recorded.   It  is
       expected  that inode numbers in the disk filesystem are persistent over
       cycles of mounting and booting.  Files with names matching *.o or *.swp
       get excluded explicitly.

       To  be used several times on the same medium, whenever an update of the
       two disk trees to the medium is desired. Begin with a blank medium  and
       update  it until he run fails gracefully due to lack of remaining space
       on the old one.
       Always eject the drive tray between sessions.  A run of dd  shall  give
       demons a chance to spoil the first read on freshly loaded media.
         $ msinfo=$(xorriso -as cdrecord dev=/dev/sr0 -msinfo)
         $ dd if=/dev/sr0 count=1 >/dev/null 2>&1
         $ load_opts=
         $ test -n "$msinfo" && load_opts="-M /dev/sr0 -C $msinfo"
         $ xorrisofs $load_opts -o - --for_backup -m '*.o' -m '*.swp' \
           -V PROJ_MAIL_"$(date '+%Y_%m_%d_%H%M%S')" -graft-points \
           -old-root / \
           /projects=/home/thomas/projects \
           /personal_mail=/home/thomas/personal_mail \
           | xorriso -as cdrecord dev=/dev/sr0 -v -multi -waiti -eject -

       This  makes  sense  if  the  full  backup  leaves substantial remaining
       capacity on media and if the expected changes are much smaller than the
       full backup.

       Better  do  not  use your youngest backup for -old-root.  Have at least
       two media which you  use  alternatingly.  So  only  older  backups  get
       endangered  by  the  new  write  operation,  while the newest backup is
       stored safely on a different medium.
       Always have a blank medium ready to perform a full backup in  case  the
       update  attempt  fails  due  to  insufficient  remaining capacity. This
       failure will not spoil the old medium, of course.

       If  inode  numbers  on  disk  are  not  persistent,  then  use   option
       --old-root-no-ino  .   In this case an update run will compare recorded
       MD5 sums against the current file content on hard disk.

       With mount option -o "sbsector=" on  GNU/Linux  or  -s  on  FreeBSD  or
       NetBSD  it  is possible to access the session trees which represent the
       older backup versions. With CD media, GNU/Linux mount  accepts  session
       numbers directly by its option "session=".
       Multi-session  media and most overwritable media written by xorriso can
       tell the sbsectors of their sessions by xorriso option -toc:
         $ xorriso -dev /dev/sr0 -toc
       xorriso can print the matching mount command for a session number:
         $ xorriso -mount_cmd /dev/sr0 session 12 /mnt
       or for a volume id that matches a search expression:
         $ xorriso -mount_cmd /dev/sr0 volid '*2008_12_05*' /mnt
       Both yield on standard output something like:
         mount   -t   iso9660    -o    nodev,noexec,nosuid,ro,sbsector=1460256
       '/dev/sr0' '/mnt'
       The superuser may let xorriso execute the mount command directly:
         # osirrox -mount /dev/sr0 "volid" '*2008_12_05*' /mnt

   Incremental backup with accumulated trees
       Solaris does not offer the option to mount older sessions.  In order to
       keep them accessible, one may map all files to  a  file  tree  under  a
       session  directory  and  accumulate  those  directories from session to
       session.  The -root tree is cloned from the -old-root  tree  before  it
       gets compared with the appropriate trees on disk.
       This demands to know the previously used session directory name.
       With the first session:
         $ xorrisofs -root /session1 \
           -o - --for_backup -m '*.o' -m '*.swp' \
           -V PROJ_MAIL_"$(date '+%Y_%m_%d_%H%M%S')" -graft-points \
           /projects=/home/thomas/projects \
           /personal_mail=/home/thomas/personal_mail \
           | xorriso -as cdrecord dev=/dev/sr0 -v blank=as_needed \
                     -multi -waiti -eject -

       With  the  second session, option -old-root refers to /session1 and the
       new -root is /session2.
       Always eject the drive tray between sessions.  A run of dd  shall  give
       demons a chance to spoil the first read on freshly loaded media.
         $ msinfo=$(xorriso -as cdrecord dev=/dev/sr0 -msinfo)
         $ dd if=/dev/sr0 count=1 >/dev/null 2>&1
         $ load_opts=
         $ test -n "$msinfo" && load_opts="-M /dev/sr0 -C $msinfo"
         $ xorrisofs $load_opts -root /session2 -old-root /session1 \
           -o - --for_backup -m '*.o' -m '*.swp' \
           -V PROJ_MAIL_"$(date '+%Y_%m_%d_%H%M%S')" -graft-points \
           /projects=/home/thomas/projects \
           /personal_mail=/home/thomas/personal_mail \
           | xorriso -as cdrecord dev=/dev/sr0 -v -multi -waiti -eject -
       With  the third session, option -old-root refers to /session2.  The new
       -root is /session3. And so on.

   Create bootable images for PC-BIOS and EFI
       The SYSLINUX/ISOLINUX boot loader suite is popular for booting PC-BIOS.
       The  ISOLINUX  wiki  prescribes to create on disk a directory ./CD_root
       and to copy all desired files  underneath  that  directory.  Especially
       file  isolinux.bin shall be copied to ./CD_root/isolinux/isolinux.bin .
       This is the boot image file.
       The prescribed mkisofs options can be used unchanged with xorrisofs:
         $ xorrisofs -o output.iso \
             -b isolinux/isolinux.bin -c isolinux/boot.cat \
             -no-emul-boot -boot-load-size 4 -boot-info-table \
             ./CD_root
       Put it on CD by a burn program. E.g.:
         $ xorriso -as cdrecord -v dev=/dev/sr0 blank=as_needed output.iso

       The image from above example will boot from CD, DVD or BD, but not from
       USB  stick or other hard-disk-like devices. This can be done by help of
       an  isohybrid  MBR.  Syslinux  provides  matching  template  files   as
       isohdp[fp]x*.bin . E.g. /usr/lib/syslinux/isohdpfx.bin .
       If   a   few   hundred   KB   of   size  do  not  matter,  then  option
       -partition_offset can  be  used  to  create  a  partition  table  where
       partition 1 starts not at block 0. This facilitates later manipulations
       of the USB stick by tools for partitioning and formatting.
       The image from the following example will be prepared for  booting  via
       MBR and its first partition will start at hard disk block 64.
       It will also boot from optical media.
         $ xorrisofs -o output.iso \
             -b isolinux/isolinux.bin -c isolinux/boot.cat \
             -no-emul-boot -boot-load-size 4 -boot-info-table \
             -isohybrid-mbr /usr/lib/syslinux/isohdpfx.bin \
             -partition_offset 16 \
             ./CD_root
       Become  superuser  and  copy the image to the unpartitioned base device
       file of the  USB  stick.  On  GNU/Linux  this  is  e.g.  /dev/sdb,  not
       /dev/sdb1.
       CAUTION: This will overwrite any partitioning on the USB stick and make
       remaining data unaccessible.
       So first make sure you got the correct address of the intended  device.
       E.g. by reading 100 MiB data from it and watching it blinking:
         # dd bs=2K if=/dev/sdb count=50K >/dev/null
       Now copy the image onto it
         # dd bs=2K if=output.iso of=/dev/sdb

       Now for EFI:
       The  boot  image  file  has to be the image of an EFI System Partition,
       i.e. a FAT filesystem with directory /EFI/BOOT and boot files with  EFI
       prescribed  names:  BOOTIA32.EFI for 32 bit x86, BOOTx64.EFI for 64 bit
       AMD/x86 (in UEFI-2.4 there is indeed a lower  case  "x"),  BOOTAA64.EFI
       for  64  bit  ARM. The software in the FAT filesystem should be able to
       find and inspect the ISO filesystem for boot loader  configuration  and
       start  of operating system. GRUB2 program grub-mkimage can produce such
       a FAT filesystem with suitable content, which then uses  further  GRUB2
       software from the ISO filesystem.
       EFI  boot  equipment  may be combined with above ISOLINUX isohybrid for
       PC-BIOS in a not really UEFI-2.4 compliant way, which  obviously  works
       well.  It  yields  MBR  and  GPT  partition  tables,  both  with nested
       partitions.  Assumed  the  EFI  System  Partition  image  is  ready  as
       ./CD_root/boot/grub/efi.img,  add  the  following  options  before  the
       directory address ./CD_root:
             -eltorito-alt-boot -e 'boot/grub/efi.img' -no-emul-boot \
             -isohybrid-gpt-basdat \
       More compliant with UEFI-2.4 is to decide for either MBR or GPT and  to
       append  a copy of the EFI System Partition in order to avoid overlap of
       ISO partition and EFI partition. Here for MBR:
             -eltorito-alt-boot -e 'boot/grub/efi.img' -no-emul-boot \
             -append_partition 2 0xef ./CD_root/boot/grub/efi.img \
       The resulting ISOs are supposed to boot  from  optical  media  and  USB
       stick.   One may omit option -eltorito-alt-boot if no option -b is used
       to make the ISO bootable via PC-BIOS.

       For ISOs with pure GRUB2 boot equipment  consider  to  use  GRUB2  tool
       grub-mkrescue as frontend to xorrisofs.

       If  you  have  a bootable ISO filesystem and want to know its equipment
       plus a proposal how to reproduce it, try:
         $ xorriso -hfsplus on -indev IMAGE.iso \
             -report_el_torito plain -report_system_area plain \
             -print "" -print "======= Proposal for xorrisofs options:" \
             -report_el_torito as_mkisofs

FILES
   Startup files:
       If not --no_rc is given as the first argument then  xorrisofs  attempts
       on startup to read and execute lines from the following files:
          /etc/default/xorriso
          /etc/opt/xorriso/rc
          /etc/xorriso/xorriso.conf
          $HOME/.xorrisorc
       The  files  are  read  in  the sequence given here, but none of them is
       required to exist. The lines are not interpreted as  xorrisofs  options
       but as generic xorriso commands. See man xorriso.

       After  the  xorriso startup files, the program tries one by one to open
       for reading:
          ./.mkisofsrc
          $MKISOFSRC
          $HOME/.mkisofsrc
          $(dirname $0)/.mkisofsrc
       On success it interprets the file content  and  does  not  try  further
       files.   The  last  address  is  used  only  if  start argument 0 has a
       non-trivial dirname.
       The reader currently interprets the following NAME=VALUE pairs:
        APPI default for -A
        PUBL default for -publisher
        SYSI default for -sysid
        VOLI default for -V
        VOLS default for -volset
       Any other lines will be silently ignored.

ENVIRONMENT
       The following environment variables influence the program behavior:
       HOME is used to find xorriso and mkisofs startup files.
       MKISOFSRC may be used to point the program to a mkisofs startup file.
       SOURCE_DATE_EPOCH belongs to the specs of reproducible-builds.org.   It
       is supposed to be either undefined or to contain a decimal number which
       tells the seconds since january 1st 1970. If it contains a number, then
       it  is  used  as time value to set the default of --modification-date=.
       --gpt_disk_guid  defaults  to  "modification-date".   The  default   of
       --set_all_file_dates  is  then  "set_to_mtime".  Further the "now" time
       for ISO nodes without disk source is then set to the  SOURCE_DATE_EPOCH
       value.
       Startup   files   and  program  options  can  override  the  effect  of
       SOURCE_DATE_EPOCH.



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+--------------------+
       |ATTRIBUTE TYPE |  ATTRIBUTE VALUE   |
       +---------------+--------------------+
       |Availability   | media/xorriso-core |
       +---------------+--------------------+
       |Stability      | Uncommitted        |
       +---------------+--------------------+

SEE ALSO
       For generic xorriso command mode
              xorriso(1)

       For the cdrecord emulation of xorriso
              xorrecord(1)

       For mounting xorriso generated ISO 9660 images (-t iso9660)
              mount(8)

       Other programs which produce ISO 9660 images
              mkisofs(8), genisoimage(8)

       Programs which burn sessions to optical media
              growisofs(1), cdrecord(1), wodim(1), cdrskin(1), xorriso(1)

       ACL and xattr
              getfacl(1), setfacl(1), getfattr(1), setfattr(1)

       MD5 checksums
              md5sum(1)

       On FreeBSD the commands for xattr and MD5 differ
              getextattr(8), setextattr(8), md5(1)

BUGS
       To report bugs, request help,  or  suggest  enhancements  for  xorriso,
       please  send  electronic mail to the public list <bug-xorriso@gnu.org>.
       If more privacy is desired, mail to <scdbackup@gmx.net>.
       Please describe what you expect xorriso to do, the program arguments or
       dialog  commands  by  which  you  tried  to achieve it, the messages of
       xorriso, and the undesirable outcome of your program run.
       Expect to get asked more questions before solutions can be proposed.

AUTHOR
       Thomas Schmitt <scdbackup@gmx.net>
       for libburnia-project.org

COPYRIGHT
       Copyright (c) 2011 - 2021 Thomas Schmitt
       Permission is granted to distribute this text freely. It shall only  be
       modified  in sync with the technical properties of xorriso. If you make
       use of the license to derive modified versions of xorriso then you  are
       entitled to modify this text under that same license.

CREDITS
       xorrisofs  is  in  part  based  on  work by Vreixo Formoso who provides
       libisofs together with Mario Danic who also leads the  libburnia  team.
       Vladimir  Serbinenko  contributed  the HFS+ filesystem code and related
       knowledge.
       Compliments towards Joerg Schilling whose cdrtools served  me  for  ten
       years.



NOTES
       Source  code  for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source                was                downloaded                from
       https://ftp.gnu.org/gnu/xorriso/xorriso-1.5.4.pl02.tar.gz.

       Further information about this software can be found on the open source
       community website at https://www.gnu.org/software/xorriso.



                                                   Version 1.5.4, Jan 30, 2021
                                                                  XORRISOFS(1)