XORRISO(1)

NAME
xorriso - creates, loads, manipulates and writes ISO 9660 filesystem images with Rock Ridge extensions.

SYNOPSIS
xorriso [settings|actions]

DESCRIPTION

xorriso is a program which copies file objects from POSIX compliant filesystems into Rock Ridge enhanced ISO 9660 filesystems and allows session-wise manipulation of such filesystems. It can load the management information of existing ISO images and it writes the session results to optical media or to filesystem objects.
Vice versa xorriso is able to copy file objects out of ISO 9660 filesystems.

A special property of xorriso is that it needs neither an external ISO 9660 formatter program nor an external burn program for CD, DVD or BD but rather incorporates the libraries of libburnia-project.org .

  Overview of features:
Operates on an existing ISO image or creates a new one.
Copies files from disk filesystem into the ISO image.
Copies files from ISO image to disk filesystem (see osirrox).
Renames or deletes file objects in the ISO image.
Changes file properties in the ISO image.
Updates ISO subtrees incrementally to match given disk subtrees.
Writes result either as completely new image or as add-on session to optical media or filesystem objects.
Can activate ISOLINUX and GRUB boot images via El Torito and MBR.
Can perform multi-session tasks as emulation of mkisofs and cdrecord.
Can record and restore hard links and ACL.
Content may get zisofs compressed or filtered by external processes.
Can issue commands to mount older sessions on GNU/Linux or FreeBSD.
Can check media for damages and copy readable blocks to disk.
Can attach MD5 checksums to each data file and the whole session.
Scans for optical drives, blanks re-useable optical media.
Reads its instructions from command line arguments, dialog, and files.
Provides navigation commands for interactive ISO image manipulation.
Adjustable thresholds for abort, exit value, and problem reporting.

  General information paragraphs:
Session model
Media types and states
Creating, Growing, Modifying, Blind Growing
Libburn drives
Rock Ridge, POSIX, X/Open, El Torito, ACL, xattr
Command processing
Dialog, Readline, Result pager

Maybe you first want to have a look at section EXAMPLES near the end of this text before reading the next few hundred lines of background information.

  Session model:
Unlike other filesystems, ISO 9660 is not intended for read-write operation but rather for being generated in a single sweep and being written to media as a session.
The data content of the session is called filesystem image.

The written image in its session can then be mounted by the operating system for being used read-only. GNU/Linux is able to mount ISO images from block devices, which may represent optical media, other media or via a loop device even from regular disk files. FreeBSD mounts ISO images from devices that represent arbitrary media or from regular disk files.

This session usage model has been extended on CD media by the concept of multi-session , which allows to add information to the CD and gives the mount programs of the operating systems the addresses of the entry points of each session. The mount programs recognize block devices which represent CD media and will by default mount the image in the last session.
This session usually contains an updated directory tree for the whole medium which governs the data contents in all recorded sessions. So in the view of the mount program all sessions of a particular medium together form a single filesystem image.
Adding a session to an existing ISO image is in this text referred as growing.
The multi-session model of the MMC standard does not apply to all media types. But program growisofs by Andy Polyakov showed how to extend this functionality to overwriteable media or disk files which carry valid ISO 9660 filesystems.

xorriso provides growing as well as an own method named modifying which produces a completely new ISO image from the old one and the modifications. See paragraph Creating, Growing, Modifying, Blind Growing below.

xorriso adopts the concept of multi-session by loading an image directory tree if present, by allowing to manipulate it by several actions, and by writing the new image to the target medium.
The first session of a xorriso run begins by the definition of the input drive with the ISO image or by the definition of an output drive. The session ends by command -commit which triggers writing. A -commit is done automatically when the program ends regularly.

After -commit a new session begins with the freshly written one as input. A new input drive can only be chosen as long as the loaded ISO image was not altered. Pending alteration can be revoked by command -rollback.

Writing a session to the target is supposed to be very expensive in terms of time and of consumed space on appendable or write-once media. Therefore all intended manipulations of a particular ISO image should be done in a single session. But in principle it is possible to store intermediate states and to continue with image manipulations.

  Media types and states:
There are two families of media in the MMC standard:
Multi-session media are CD-R, CD-RW, DVD-R, DVD+R, DVD+R/DL, BD-R, and unformatted DVD-RW. These media provide a table of content which describes their existing sessions. See option -toc.
Similar to multi-session media are DVD-R DL and minimally blanked DVD-RW. They allow only a single session of which the size must be known in advance. xorriso will write onto them only if option -close is set to "on".
Overwriteable media are DVD-RAM, DVD+RW, BD-RE, and formatted DVD-RW. They allow random write access but do not provide information about their session history. If they contain one or more ISO 9660 sessions and if the first session was written by xorriso, then a table of content can be emulated. Else only a single overall session will be visible.
DVD-RW media can be formatted by -format "full". They can be made unformatted by -blank "deformat".
Regular files and block devices are handled as overwriteable media. Pipes and other writeable file types are handled as blank multi-session media.

These media can assume several states in which they offer different capabilities.
Blank media can be written from scratch. They contain no ISO image suitable for xorriso.
Blank is the state of newly purchased optical media. With used CD-RW and DVD-RW it can be achieved by action -blank "as_needed". Overwriteable media are considered blank if they are new or if they have been marked as blank by xorriso. Action -blank "as_needed" can be used to do this marking on overwriteable media, or to apply mandatory formatting to new media if necessary.
Appendable media accept further sessions. Either they are MMC multi-session media in appendable state, or they are overwriteable media which contain an ISO image suitable for xorriso.
Appendable is the state after writing a session with option -close off.
Closed media cannot be written. They may contain an ISO image suitable for xorriso.
Closed is the state of DVD-ROM media and of multi-session media which were written with option -close on. If the drive is read-only hardware then it will probably show any media as closed CD-ROM resp. DVD-ROM.
Overwriteable media assume this state in such read-only drives or if they contain unrecognizable data in the first 32 data blocks.
Read-only drives may or may not show session histories of multi-session media. Often only the first and the last session are visible. Sometimes not even that. Option -rom_toc_scan might or might not help in such cases.

  Creating, Growing, Modifying, Blind Growing:
A new empty ISO image gets created if there is no input drive with a valid ISO 9660 image when the first time an output drive is defined. This is achieved by option -dev on blank media or by option -outdev on media in any state.
The new empty image can be populated with directories and files. Before it can be written, the medium in the output drive must get into blank state if it was not blank already.

If there is a input drive with a valid ISO image, then this image gets loaded as foundation for manipulations and extension. The constellation of input and output drive determines which write method will be used. They have quite different capabilities and constraints.

The method of growing adds new data to the existing data on the medium. These data comprise of new file content and they override the existing ISO 9660 + Rock Ridge directory tree. It is possible to hide files from previous sessions but they still exist on the medium and with many types of optical media it is quite easy to recover them by mounting older sessions.
Growing is achieved by option -dev.

The write method of modifying produces compact filesystem images with no outdated files or directory trees. Modifying can write its images to target media which are completely unsuitable for multi-session operations. E.g. DVD-RW which were treated with -blank deformat_quickest, DVD-R DL, named pipes, character devices, sockets. On the other hand modified sessions cannot be written to appendable media but to blank media only.
So for this method one needs either two optical drives or has to work with filesystem objects as source and/or target medium.
Modifying takes place if input drive and output drive are not the same and if option -grow_blindly is set to its default "off". This is achieved by options -indev and -outdev.

If option -grow_blindly is set to a non-negative number and if -indev and -outdev are both set to different drives, then blind growing is performed. It produces an add-on session which is ready for being written to the given block address. This is the usage model of
 mkisofs -M $indev -C $msc1,$msc2 -o $outdev
which gives much room for wrong parameter combinations and should thus only be employed if a strict distinction between ISO formatter xorriso and the burn program is desired. -C $msc1,$msc2 is equivalent to:
 -load sbsector $msc1 -grow_blindly $msc2

  Libburn drives:
Input drive, i.e. source of an existing or empty ISO image, can be any random access readable libburn drive: optical media with readable data, blank optical media, regular files, block devices.

Output drive, i.e. target for writing, can be any libburn drive. Some drive types do not support the method of growing but only the methods of modifying and blind growing. They all are suitable for newly created images.
All drive file objects have to offer rw-permission to the user of xorriso. Even those which will not be useable for reading an ISO image.

MMC compliant (i.e. optical) drives on GNU/Linux usually get addressed by the path of their block device or of their generic character device. E.g.
  -dev /dev/sr0
  -dev /dev/hdc
  -dev /dev/sg2
On FreeBSD the device files have names like
  -dev /dev/cd0
On OpenSolaris:
  -dev /dev/rdsk/c4t0d0s2
Get a list of accessible drives by command
  -device_links
It might be necessary to do this as superuser in order to see all drives and to then allow rw-access for the intended users. Consider to bundle the authorized users in a group like old "floppy".

Filesystem objects of nearly any type can be addressed by prefix "stdio:" and their path in the filesystem. E.g.:
  -dev stdio:/dev/sdc
The default setting of -drive_class allows to address files outside the /dev tree without that prefix. E.g.:
  -dev /tmp/pseudo_drive
If path leads to a regular file or to a block device then the emulated drive is random access readable and can be used for the method of growing if it already contains a valid ISO 9660 image. Any other file type is not readable via "stdio:" and can only be used as target for the method of modifying or blind growing. Non-existing paths in existing directories are handled as empty regular files.

A very special kind of pseudo drive are open file descriptors. They are depicted by "stdio:/dev/fd/" and descriptor number (see man 2 open).
Addresses "-" or "stdio:/dev/fd/1" depict standard output, which normally is the output channel for result texts. To prevent a fatal intermingling of ISO image and text messages, all result texts get redirected to stderr if -*dev "-" or "stdio:/dev/fd/1" is among the start arguments of the program.
Standard output is currently suitable for creating one session per program run without dialog. Use in other situations is discouraged and several restrictions apply:
It is not allowed to use standard output as pseudo drive if it was not among the start arguments. Do not try to fool this ban via backdoor addresses to stdout.
If stdout is used as drive, then -use_readline is permanently disabled. Use of backdoors can cause severe memory and/or tty corruption.

Be aware that especially the superuser can write into any accessible file or device by using its path with the "stdio:" prefix. By default any address in the /dev tree without prefix "stdio:" will work only if it leads to a MMC drive.
One may use option -ban_stdio_write to surely prevent this risk and to allow only MMC drives.
One may prepend "mmc:" to a path to surely disallow any automatic "stdio:".
By option -drive_class one may ban certain paths or allow access without prefix "stdio:" to other paths.

  Rock Ridge, POSIX, X/Open, El Torito, ACL, xattr:
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.
This is what xorriso uses for a decent representation of the disk files within the ISO image. Rock Ridge information is produced with any xorriso image.

xorriso is not named "porriso" because POSIX only guarantees 14 characters of filename length. It is the X/Open System Interface standard XSI which demands a file name length of up to 255 characters and paths of up to 1024 characters. Rock Ridge fulfills this demand.

An El Torito boot record points the BIOS bootstrapping facility to 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.
Most bootable GNU/Linux CDs are equipped with ISOLINUX or GRUB boot images. xorriso is able to create or maintain an El Torito object which makes such an image bootable. For details see option -boot_image.
It is possible to make ISO images bootable from USB stick or other hard-disk-like media by -boot_image argument system_area= . This installs a Master Boot Record which may get adjusted according to the needs of GRUB resp. ISOLINUX. An MBR contains boot code and a partition table. It does not hamper CDROM booting. The new MBR of a follow-up session can get in effect only on overwriteable media.
Emulation -as mkisofs 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.
There is support for boot facilities other than PC BIOS: EFI, MIPS Big Endian (SGI), MIPS Little Endian (DEC), SUN SPARC.

ACL are an advanced way of controlling access permissions to file objects. Neither ISO 9660 nor Rock Ridge specify a way to record ACLs. So libisofs has introduced a standard conformant extension named AAIP for that purpose. It uses this extension if enabled by option -acl.
AAIP enhanced images are supposed to be mountable normally, but one cannot expect that the mounted filesystem will show and respect the ACLs. For now, only xorriso is able to retrieve those ACLs. It can bring them into effect when files get restored to an ACL enabled file system or it can print them in a format suitable for tool setfacl.
Files with ACL show as group permissions the setting of entry "mask::" if that entry exists. Nevertheless the non-listed group members get handled according to entry "group::". When removing ACL from a file, xorriso brings "group::" into effect.
Recording and restoring of ACLs from and to local files works currently only on GNU/Linux and FreeBSD.

xattr (aka EA, or extattr) are pairs of name and value which can be attached to file objects. AAIP is able to represent them and xorriso allows to record and restore pairs which have names out of the user namespace. I.e. those which begin with "user.", like "user.x" or "user.whatever". Name has to be a 0 terminated string. Value may be any array of bytes which does not exceed the size of 4095 bytes. xattr processing happens only if it is enabled by option -xattr.
As with ACL, currently only xorriso is able to retrieve xattr from AAIP enhanced images, to restore them to xattr capable file systems, or to print them.
Recording and restoring of xattr from and to local files works currently only on GNU/Linux and FreeBSD, where they are known as extattr.

  Command processing:
Commands are either actions which happen immediately or settings which influence following actions. So their sequence does matter.
Commands consist of a command word, followed by zero or more parameter words. If the list of parameter words is of variable length (indicated by "[...]" or "[***]") then it has to be terminated by either the list delimiter, or the end of argument list, or an end of an input line.

At program start the list delimiter is the word "--". This may be changed by option -list_delimiter in order to allow "--" as argument in a list of variable length. It is advised to reset the delimiter to "--" immediately afterwards.
For brevity the list delimiter is referred as "--" throughout this text.
The list delimiter is silently tolerated if it appears after the parameters of a command with a fixed list length. It is handled as normal text if it appears among the arguments of such a command.

Pattern expansion converts a list of pattern words into a list of existing file addresses. Unmatched pattern words appear themselves in that result list, though.
Pattern matching supports the usual shell parser wildcards '*' '?' '[xyz]' and respects '/' as separator which may only be matched literally.
It is a property of some particular commands and not a general feature. It gets controlled by commands -iso_rr_pattern and -disk_pattern. Commands which may use pattern expansion all have variable argument lists which are marked in this man page by "[***]" rather than "[...]".
Some other commands perform pattern matching unconditionally.

Command and parameter words are either read from program arguments, where one argument is one word, or from quoted input lines where words are recognized similar to the quotation rules of a shell parser.
xorriso is not a shell, although it might appear so on first glimpse. Be aware that the interaction of quotation marks and pattern symbols like "*" differs from the usual shell parsers. In xorriso, a quotation mark does not make a pattern symbol literal.

Quoted input converts whitespace separated text pieces into words. The double quotation mark " and the single quotation mark ' can be used to enclose whitespace and make it part of words (e.g. of file names). 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.
Quoted input accepts any ASCII character except NUL (0) as content of quotes. Nevertheless it can be cumbersome for the user to produce those characters at all. Therefore quoted input and program arguments allow optional Backslash Interpretation which can represent all ASCII characters except NUL (0) by backslash codes as in $'...' of bash.
It is not enabled by default. See option -backslash_codes.

When the program starts then it first looks for argument -no_rc. If this is not present then it looks for its startup files and reads their content as command input lines. Then it interprets the program arguments as commands and parameters. Finally it enters dialog mode if command -dialog "on" was executed up to then.

The program ends either by command -end, or by the end of program arguments if not dialog was enabled up to that moment, or by a problem event which triggers the threshold of command -abort_on.

  Dialog, Readline, Result pager:
Dialog mode prompts for a quoted input line, parses it into words, and performs them as commands with their parameters. It provides assisting services to make dialog more comfortable.

Readline is an enhancement for the input line. You may know it already from the bash shell. Whether it is available in xorriso depends on the availability of package readline-dev at the time when xorriso was built from its sourcecode.
It allows to move the cursor over the text in the line by help of the Leftward and the Rightward arrow key. Text may be inserted at the cursor position. The Delete key removes the character under the cursor. Upward and Downward arrow keys navigate through the history of previous input lines.
See man readline for more info about libreadline.

Option -page activates a built-in result text pager which may be convenient in dialog. After an action has put out the given number of terminal lines, the pager prompts the user for a line of input.
An empty line lets xorriso resume work until the next page is put out.
The single character "@" disables paging for the current action.
"@@@", "x", "q", "X", or "Q" urge the current action to abort and suppress further result output.
Any other line will be interpreted as new dialog line. The current action is urged to abort. Afterwards, the input line is executed.

Some actions apply paging to their info output, too.
The urge to abort may or may not be obeyed by the current action. All actions try to abort as soon as possible.

OPTIONS
All command words are shown with a leading dash although this dash is not mandatory for the option to be recognized. Nevertheless within option -as the dashes of the emulated options are mandatory.
Normally any number of leading dashes is ignored with command words and inner dashes are interpreted as underscores.

Aquiring source and target drive:

The effect of aquiring a drive may depend on several options in the next paragraph "Influencing the behavior of image loading". If desired, their enabling commands have to be performed before the commands which aquire the drive.

-dev address
    Set input and output drive to the same address and load an ISO image if it is present. If there is no ISO image then create a blank one. Set the image expansion method to growing.
    This is only allowed as long as no changes are pending in the currently loaded ISO image. If changes are pending, then one has to perform -commit or -rollback first.
    Special address string "-" means standard output, to which several restrictions apply. See above paragraph "Libburn drives".
    An empty address string "" gives up the current device without aquiring a new one.

-indev address
    Set input drive and load an ISO image if present. If the new input drive differs from -outdev then switch from growing to modifying or to blind growing. It depends on the setting of -grow_blindly which of both gets activated. The same rules and restrictions apply as with -dev.

-outdev address
    Set output drive and if it differs from the input drive then switch from growing to modifying or to blind growing. Unlike -dev and -indev this action does not load a new ISO image. So it can be performed even if there are pending changes.
    -outdev can be performed without previous -dev or -indev. In that case an empty ISO image with no changes pending is created. It can either be populated by help of -map, -add et.al. or it can be discarded silently if -dev or -indev are performed afterwards.
    Special address string "-" means standard output, to which several restrictions apply. See above paragraph "Libburn drives".
    An empty address string "" gives up the current output drive without aquiring a new one. No writing is possible without an output drive.

-grow_blindly "off"|predicted_nwa
    If predicted_nwa is a non-negative number then perform blind growing rather than modifying if -indev and -outdev are set to different drives. "off" or "-1" switch to modifying, which is the default.
    predicted_nwa is the block address where the add-on session of blind growing will finally end up. It is the responsibility of the user to ensure this final position and the presence of the older sessions. Else the overall ISO image will not be mountable or will produce read errors when accessing file content. xorriso will write the session to the address as obtained from examining -outdev and not necessarily to predicted_nwa.
    During a run of blind growing, the input drive is given up before output begins. The output drive is given up when writing is done.

Influencing the behavior of image loading:

The following options should normally be performed before loading an image by aquiring an input drive. In rare cases it is desirable to activate them only after image loading.

-load entity id
    Load a particular (possibly outdated) ISO session from -dev or -indev. Usually all available sessions are shown with option -toc.
    entity depicts the kind of addressing. id depicts the particular address. The following entities are defined:
    "auto" with any id addresses the last session in -toc. This is the default.
    "session" with id being a number as of a line "ISO session", column "Idx".
    "track" with id being a number as of a line "ISO track", column "Idx".
    "lba" or "sbsector" with a number as of a line "ISO ...", column "sbsector".
    "volid" with a search pattern for a text as of a line "ISO ...", column "Volume Id".
    Adressing a non-existing entity or one which does not represent an ISO image will either abandon -indev or at least lead to a blank image.
    If an input drive is set at the moment when -load is executed, then the addressed ISO image is loaded immediately. Else, the setting will be pending until the next -dev or -indev. After the image has been loaded once, the setting is valid for -rollback until next -dev or -indev, where it will be reset to "auto".

-displacement [-]lba
    Compensate a displacement of the image versus the start address for which the image was prepared. This affects only loading of ISO images and reading of their files. The multi-session method of growing is not allowed as long as -displacement is non-zero. I.e. -indev and -outdev must be different. The displacement gets reset to 0 before the drive gets re-aquired after writing.
    Examples:
    If a track of a CD starts at block 123456 and gets copied to a disk file where it begins at block 0, then this copy can be loaded with -displacement -123456.
    If an ISO image was written onto a partition with offset of 640000 blocks of 512 bytes, then it can be loaded from the base device by -displacement 160000.
    In both cases, the ISO sessions should be self contained, i.e. not add-on sessions to an ISO image outside their track resp. partition.

-drive_class "harmless"|"banned"|"caution"|"clear_list" disk_pattern
    Add a drive path pattern to one of the safety lists or make those lists empty. There are three lists defined which get tested in the following sequence:
    If a drive address path matches the "harmless" list then the drive will be accepted. If it is not a MMC device then the prefix "stdio:" will be prepended automatically. This list is empty by default.
    Else if the path matches the "banned" list then the drive will not be accepted by xorriso but rather lead to a FAILURE event. This list is empty by default.
    Else if the path matches the "caution" list and if it is not a MMC device, then its address must have the prefix "stdio:" or it will be rejected. This list has by default one entry: "/dev".
    If a drive path matches no list then it is considered "harmless". By default these are all paths which do not begin with directory "/dev".
    A path matches a list if one of its parent paths or itself matches a list entry. Address prefix "stdio:" or "mmc:" will be ignored when testing for matches.
    By pseudo-class "clear_list" and pseudo-patterns "banned", "caution", "harmless", or "all", the lists may be made empty.
    E.g.: -drive_class clear_list banned
    One will normally define the -drive_class lists in one of the xorriso Startup Files.
    Note: This is not a security feature but rather a bumper for the superuser to prevent inadverted mishaps. For reliably blocking access to a device file you have to deny its rw-permissions in the filesystem.

-assert_volid pattern severity
    Refuse to load ISO images with volume ids which do not match the given search pattern. When refusing an image, give up the input drive and issue an event of the given severity (like FAILURE, see -abort_on). An empty search pattern accepts any image.
    This option does not hamper the creation of an empty image from blank input media and does not discard an already loaded image.

-in_charset character_set_name
    Set the character set from which to convert file names when loading an image. See paragraph "Character sets" for more explanations. When loading the written image after -commit the setting of -out_charset will be copied to -in_charset.

-auto_charset "on"|"off"
    Enable or disable recording and interpretation of the output character set name in an xattr attribute of the image root directory. If enabled and if a recorded character set name is found, then this name will be used as namoe of the input character set when reading an image.
    Note that the default output charset is the local character set of the terminal where xorriso runs. Before attributing this local character set to the produced ISO image, check whether the terminal properly displays all intended filenames, especially exotic national characters.

-hardlinks mode[:mode...]
    Enable or disable loading and recording of hardlink relations.
    In default mode "off", iso_rr files lose their inode numbers at image load time. Each iso_rr file object which has no inode number at image generation time will get a new unique inode number if -compliance is set to new_rr.
    Mode "on" preserves inode numbers from the loaded image if such numbers were recorded. When committing a session it searches for families of iso_rr files which stem from the same disk file, have identical content filtering and have identical properties. The family members all get the same inode number. Whether these numbers are respected at mount time depends on the operating system.
    Commands -update and -update_r track splits and fusions of hard links in filesystems which have stable device and inode numbers. This can cause automatic last minute changes before the session gets written. Command -hardlinks "perform_update" may be used to do these changes earlier, e.g. if you need to apply filters to all updated files.
    Mode "without_update" avoids hardlink processing during update commands. Use this if your filesystem situation does not allow -disk_dev_ino "on".
    xorriso commands which extract files from an ISO image try to hardlink files with identical inode number. The normal scope of this operation is from image load to image load. One may give up the accumulated hard link addresses by -hardlinks "discard_extract".
    A large number of hardlink families may exhaust -temp_mem_limit if not -osirrox "sort_lba_on" and -hardlinks "cheap_sorted_extract" are both in effect. This restricts hard linking to other files restored by the same single extract command. -hardlinks "normal_extract" re-enables wide and expensive hardlink accumulation.

-acl "on"|"off"
    Enable or disable processing of ACLs. If enabled, then xorriso will obtain ACLs from disk file objects, store ACLs in the ISO image using the libisofs specific AAIP format, load AAIP data from ISO images, test ACL during file comparison, and restore ACLs to disk files when extracting them from ISO images. See also options -getfacl, -setfacl.

-xattr "on"|"off"
    Enable or disable processing of xattr attributes in user namespace. If enabled, then xorriso will handle xattr similar to ACL. See also options -getfattr, -setfattr and above paragraph about xattr.

-md5 "on"|"all"|"off"|"load_check_off"
    Enable or disable processing of MD5 checksums for the overall session and for each single data file. If enabled then images with checksum tags get loaded only if the tags of superblock and directory tree match properly. The MD5 checksums of data files and whole session get loaded from the image if there are any.
    With options -compare and -update the recorded MD5 of a file will be used to avoid content reading from the image. Only the disk file content will be read and compared with that MD5. This can save much time if -disk_dev_ino "on" is not suitable.
    At image generation time they are computed for each file which gets its data written into the new session. The checksums of files which have their data in older sessions get copied into the new session. Superblock, tree and whole session get a checksum tag each.
    Mode "all" will additionally check during image generation whether the checksum of a data file changed between the time when its reading began and the time when it ended. This implies reading every file twice.
    Mode "load_check_off" together with "on" or "all" will load recorded MD5 sums but not test the recorded checksum tags of superblock and directory tree. This is necessary if growisofs was used as burn program, because it does not overwrite the superblock checksum tag of the first session. Therefore load_check_off is in effect when xorriso -as mkisofs option -M is performed.
    The test can be re-enabled by mode "load_check_on".
    Checksums can be exploited via options -check_md5, -check_md5_r, via find actions get_md5, check_md5, and via -check_media.

-for_backup
    Enable all extra features which help to produce or to restore backups with highest fidelity of file properties. Currently this is a shortcut for: -hardlinks on -acl on -xattr on -md5 on.

-disk_dev_ino "on"|"ino_only"|"off"
    Enable or disable processing of recorded file identification numbers (dev_t and ino_t). If enabled they are stored as xattr and allow to substantially accelerate file comparison. The root node gets a global start timestamp. If during comparison a file with younger timestamps is found in the ISO image, then it is suspected to have inconsistent content.
    If device numbers and inode numbers of the disk filesystems are persistent and if no irregular alterations of timestamps or system clock happen, then potential content changes can be detected without reading that content. File content change is assumed if any of mtime, ctime, device number or inode number have changed.
    Mode "ino_only" replaces the precondition that device numbers are stable by the precondition that mount points in the compared tree always lead to the same filesystems. Use this if mode "on" always sees all files changed.
    The speed advantage appears only if the loaded session was produced with -disk_dev_ino "on" too.
    Note that -disk_dev_ino "off" is totally in effect only if -hardlinks is "off", too.

-rom_toc_scan "on"|"force"|"off"[:"emul_on"|"emul_off"]
    Read-only drives do not tell the actual media type but show any media as ROM (e.g. as DVD-ROM). The session history of MMC multi-session media might be truncated to first and last session or even be completely false. (The emulated history of overwriteable media is not affected by this.)
    To have in case of failure a chance of getting the session history and especially the address of the last session, there is a scan for ISO 9660 filesystem headers which might help but also might yield worse results than the drive's table of content. At its end it can cause read attempts to invalid addresses and thus ugly drive behavior. Setting "on" enables that scan for alleged read-only media.
    Some operating systems are not able to mount the most recent session of multi-session DVD or BD. If on such a system xorriso has no own MMC capabilities then it may still find that session from a scanned table of content. Setting "force" handles any media like a ROM medium with setting "on".
    On the other hand the emulation of session history on overwriteable media can hamper reading of partly damaged media. Setting "off:emul_off" disables the elsewise trustworthy table-of-content scan for those media.
    To be in effect, the -rom_toc_scan setting has to be made before the -*dev command which aquires drive and medium.

-calm_drive "in"|"out"|"all"|"revoke"|"on"|"off"
    Reduce drive noise until it is actually used again. Some drives stay alert for substantial time after they have been used for reading. This reduces the startup time for the next drive operation but can be loud and waste energy if no i/o with the drive is expected to happen soon.
    Modes "in", "out", "all" immediately calm down -indev, -outdev, resp. both. Mode "revoke" immediately alerts both. Mode "on" causes -calm_drive to be performed automatically after each -dev, -indev, and -outdev. Mode "off" disables this.

-ban_stdio_write
    Allow for writing only the usage of MMC optical drives. Disallow to write the result into files of nearly arbitrary type. Once set, this command cannot be revoked.

-early_stdio_test "on"|"appendable_wo"|"off"
    If enabled by "on" then regular files and block devices get tested for effective access permissions. This implies to try opening those files for writing, which otherwise will happen only later and only if actual writing is desired.
    The test result is used for classifying the pseudo drives as overwriteable, read-only, write-only, or uselessly empty. This may lead to earlier detection of severe problems, and may avoid some less severe error events.
    Mode "appendable_wo" is like "on" with the additional property that non-empty write-only files are regarded as appendable rather than blank.

Inserting files into ISO image:

The following commands expect file addresses of two kinds:
disk_path is a path to an object in the local filesystem tree.
iso_rr_path is the Rock Ridge name of a file object in the ISO image. (Do not confuse with the lowlevel ISO 9660 names visible if Rock Ridge gets ignored.)

Note that in the ISO image you are as powerful as the superuser. Access permissions of the existing files in the image do not apply to your write operations. They are intended to be in effect with the read-only mounted image.

If the iso_rr_path of a newly inserted file leads to an existing file object in the ISO image, then the following collision handling happens:
If both objects are directories then they get merged by recursively inserting the subobjects from filesystem into ISO image. If other file types collide then the setting of command -overwrite decides.
Renaming of files has similar collision handling, but directories can only be replaced, not merged. Note that if the target directory exists, then -mv inserts the source objects into this directory rather than attempting to replace it.

The commands in this section alter the ISO image and not the local filesystem.

-disk_pattern "on"|"ls"|"off"
    Set the pattern expansion mode for the disk_path arguments of several commands which support this feature.
    Setting "off" disables this feature for all commands which are marked in this man page by "disk_path [***]" or "disk_pattern [***]".
    Setting "on" enables it for all those commands.
    Setting "ls" enables it only for those which are marked by "disk_pattern [***]".
    Default is "ls".

-add pathspec [...] | disk_path [***]
    Insert the given files or directory trees from filesystem into the ISO image.
    If -pathspecs is set to "on" then pattern expansion is always disabled and character '=' has a special meaning. It separates the ISO image path from the disk path:
    iso_rr_path=disk_path
    The separator '=' can be escaped by '\'. If iso_rr_path does not begin with '/' then -cd is prepended. If disk_path does not begin with '/' then -cdx is prepended.
    If no '=' is given then the word is used as both, iso_rr_path and disk path. If in this case the word does not begin with '/' then -cdx is prepended to the disk_path and -cd is prepended to the iso_rr_path.
    If -pathspecs is set to "off" then -disk_pattern expansion applies, if enabled. The resulting words are used as both, iso_rr_path and disk path. Relative path words get prepended the setting of -cdx to disk_path and the setting of -cd to iso_rr_path.

-add_plainly mode
    If set to mode "unknown" then any command word that does not begin with "-" and is not recognized as known command will be subject to a virtual -add command. I.e. it will be used as pathspec or as disk_path and added to the image. If enabled, -disk_pattern expansion applies to disk_paths.
    Mode "dashed" is similar to "unknown" but also adds unrecognized command words even if they begin with "-".
    Mode "any" announces that all further words are to be added as pathspecs or disk_paths. This does not work in dialog mode.
    Mode "none" is the default. It prevents any words from being understood as files to add, if they are not parameters to appropriate commands.

-path_list disk_path
    Like -add but read the parameter words from file disk_path or standard input if disk_path is "-". The list must contain exactly one pathspec resp. disk_path pattern per line.

-quoted_path_list disk_path
    Like -path_list but with quoted input reading rules. Lines get split into parameter words for -add. Whitespace outside quotes is discarded.

-map disk_path iso_rr_path
    Insert file object disk_path into the ISO image as iso_rr_path. If disk_path is a directory then its whole sub tree is inserted into the ISO image.

-map_single disk_path iso_rr_path
    Like -map, but if disk_path is a directory then its sub tree is not inserted.

-map_l disk_prefix iso_rr_prefix disk_path [***]
    Perform -map with each of the disk_path arguments. iso_rr_path will be composed from disk_path by replacing disk_prefix by iso_rr_prefix.

-update disk_path iso_rr_path
    Compare file object disk_path with file object iso_rr_path. If they do not match, then perform the necessary image manipulations to make iso_rr_path a matching copy of disk_path. By default this comparison will imply lengthy content reading before a decision is made. Options -disk_dev_ino or -md5 may accelerate comparison if they were already in effect when the loaded session was recorded.
    If disk_path is a directory and iso_rr_path does not exist yet, then the whole subtree will be inserted. Else only directory attributes will be updated.

-update_r disk_path iso_rr_path
    Like -update but working recursively. I.e. all file objects below both addresses get compared whether they have counterparts below the other address and whether both counterparts match. If there is a mismatch then the necessary update manipulation is done.
    Note that the comparison result may depend on option -follow. Its setting should always be the same as with the first adding of disk_path as iso_rr_path.
    If iso_rr_path does not exist yet, then it gets added. If disk_path does not exist, then iso_rr_path gets deleted.

-update_l disk_prefix iso_rr_prefix disk_path [***]
    Perform -update_r with each of the disk_path arguments. iso_rr_path will be composed from disk_path by replacing disk_prefix by iso_rr_prefix.

-cut_out disk_path byte_offset byte_count iso_rr_path
    Map a byte interval of a regular disk file into a regular file in the ISO image. This may be necessary if the disk file is larger than a single medium, or if it exceeds the traditional limit of 2 GiB - 1 for old operating systems, or the limit of 4 GiB - 1 for newer ones. Only the newest Linux kernels seem to read properly files >= 4 GiB - 1.
    A clumsy remedy for this limit is to backup file pieces and to concatenate them at restore time. A well tested chopping size is 2047m. It is permissible to request a higher byte_count than available. The resulting file will be truncated to the correct size of a final piece. To request a byte_offset higher than available yields no file in the ISO image but a SORRY event. E.g:
     -cut_out /my/disk/file 0 2047m \
     /file/part_1_of_3_at_0_with_2047m_of_5753194821 \
     -cut_out /my/disk/file 2047m 2047m \
     /file/part_2_of_3_at_2047m_with_2047m_of_5753194821 \
     -cut_out /my/disk/file 4094m 2047m \
     /file/part_3_of_3_at_4094m_with_2047m_of_5753194821
    While option -split_size is set larger than 0, and if all pieces of a file reside in the same ISO directory with no other files, and if the names look like above, then their ISO directory will be recognized and handled like a regular file. This affects options -compare*, -update*, and overwrite situations. See option -split_size for details.

-cpr disk_path [***] iso_rr_path
    Insert the given files or directory trees from filesystem into the ISO image.
    The rules for generating the ISO addresses are similar as with shell command cp -r. Nevertheless, directories of the iso_rr_path are created if necessary. Especially a not yet existing iso_rr_path will be handled as directory if multiple disk_paths are present. The leafnames of the multiple disk_paths will be grafted under that directory as would be done with an existing directory.
    If a single disk_path is present then a non-existing iso_rr_path will get the same type as the disk_path.
    If a disk_path does not begin with '/' then -cdx is prepended. If the iso_rr_path does not begin with '/' then -cd is prepended.

-mkdir iso_rr_path [...]
    Create empty directories if they do not exist yet. Existence as directory generates a WARNING event, existence as other file causes a FAILURE event.

-clone iso_rr_path_original iso_rr_path_copy
    Create a copy of the ISO file object iso_rr_path_original with the new address iso_rr_path_copy. If the original is a directory then copy all files and directories underneath. If iso_rr_path_original is a boot catalog file, then it gets not copied but is silently ignored.
    The copied ISO file objects have the same attributes. Copied data files refer to the same content source as their originals. The copies may then be manipulated independendly of their originals.
    This command will refuse execution if the address iso_rr_path_copy already exists in the ISO tree.

-cp_clone iso_rr_path_original [***] iso_rr_path_dest
    Create copies of one or more ISO file objects as with command -clone. In case of collision merge directories with existing ones, but do not overwrite existing ISO file objects.
    The rules for generating the copy addresses are the same as with command -cpr (see above) resp. shell command cp -r. Other than with -cpr, relative iso_rr_path_original will get prepended the -cd path and not the -cdx path. Consider to -mkdir iso_rr_path_dest before -cp_clone so the copy address does not depend on the number of iso_rr_path_original arguments.

Settings for file insertion:

-file_size_limit value [value [...]] --
    Set the maximum permissible size for a single data file. The values get summed up for the actual limit. If the only value is "off" then the file size is not limited by xorriso. Default is a limit of 100 extents, 4g -2k each:
     -file_size_limit 400g -200k --
    When mounting ISO 9660 filesystems, old operating systems can handle only files up to 2g -1 --. Newer ones are good up to 4g -1 --. You need quite a new Linux kernel to read correctly the final bytes of a file >= 4g if its size is not aligned to 2048 byte blocks.
    xorriso's own data read capabilities are not affected by operating system size limits. Such limits apply to mounting only. Nevertheless, the target filesystem of an -extract must be able to take the file size.

-not_mgt code[:code[...]]
    Control the behavior of the exclusion lists.
    Exclusion processing happens before disk_paths get mapped to the ISO image and before disk files get compared with image files. The absolute disk path of the source is matched against the -not_paths list. The leafname of the disk path is matched against the patterns in the -not_leaf list. If a match is detected then the disk path will not be regarded as an existing file and not be added to the ISO image.
    Several codes are defined. The _on/_off settings persist until they are revoked by their_off/_on counterparts.
    "erase" empties the lists which were accumulated by -not_paths and -not_leaf.
    "reset" is like "erase" but also re-installs default behavior.
    "off" disables exclusion processing temporarily without invalidating the lists and settings.
    "on" re-enables exclusion processing.
    "param_off" applies exclusion processing only to paths below disk_path parameter of commands. I.e. explicitly given disk_paths are exempted from exclusion processing.
    "param_on" applies exclusion processing to command parameters as well as to files below such parameters.
    "subtree_off" with "param_on" excludes parameter paths only if they match a -not_paths item exactly.
    "subtree_on" additionally excludes parameter paths which lead to a file address below any -not_paths item.
    "ignore_off" treats excluded disk files as if they were missing. I.e. they get reported with -compare and deleted from the image with -update.
    "ignore_on" keeps excluded files out of -compare or -update activities.

-not_paths disk_path [***]
    Add the given paths to the list of excluded absolute disk paths. If a given path is relative, then the current -cdx is prepended to form an absolute path. Pattern matching, if enabled, happens at definition time and not when exclusion checks are made.
    (Do not forget to end the list of disk_paths by "--")

-not_leaf pattern
    Add a single shell parser style pattern to the list of exclusions for disk leafnames. These patterns are evaluated when the exclusion checks are made.

-not_list disk_path
    Read lines from disk_path and use each of them either as -not_paths argument, if they contain a / character, or as -not_leaf pattern.

-quoted_not_list disk_path
    Like -not_list but with quoted input reading rules. Each word is handled as one argument for -not_paths resp. -not_leaf.

-follow occasion[:occasion[...]]
    Enable or disable resolution of symbolic links and mountpoints under disk_paths. This applies to actions -add, -du*x, -ls*x, -findx, and to -disk_pattern expansion.
    There are two kinds of follow decisison to be made:
    "link" is the hop from a symbolic link to its target file object. If enabled then symbolic links are handled as their target file objects, else symbolic links are handled as themselves.
    "mount" is the hop from one filesystem to another subordinate filesystem. If enabled then mountpoint directories are handled as any other directory, else mountpoints are handled as empty directories if they are encountered in directory tree traversals.
    Less general than above occasions:
    "pattern" is mount and link hopping, but only during -disk_pattern expansion.
    "param" is link hopping for parameter words (after eventual pattern expansion). If enabled then -ls*x will show the link targets rather than the links themselves. -du*x, -findx, and -add will process the link targets but not follow links in an eventual directory tree below the targets (unless "link" is enabled).
    Occasions can be combined in a colon separated list. All occasions mentioned in the list will then lead to a positive follow decision.
    "off" prevents any positive follow decision. Use it if no other occasion applies.
    Shortcuts:
    "default" is equivalent to "pattern:mount:limit=100".
    "on" always decides positive. Equivalent to "link:mount".
    Not an occasion but an optional setting is:
    "limit="<number> which sets the maximum number of link hops. A link hop consists of a sequence of symbolic links and a final target of different type. Nevertheless those hops can loop. Example:
      $ ln -s .. uploop
    Link hopping has a built-in loop detection which stops hopping at the first repetition of a link target. Then the repeated link is handled as itself and not as its target. Regrettably one can construct link networks which cause exponential workload before their loops get detected. The number given with "limit=" can curb this workload at the risk of truncating an intentional sequence of link hops.

-pathspecs "on"|"off"
    Control parameter interpretation with xorriso actions -add and -path_list.
    "on" enables pathspecs of the form target=source like with program mkisofs -graft-points. It also disables -disk_pattern expansion for command -add.
    "off" disables pathspecs of the form target=source and re-enables -disk_pattern expansion.

-overwrite "on"|"nondir"|"off"
    Allow or disallow to overwrite existing files in the ISO image by files with the same name.
    With setting "off", name collisions cause FAILURE events. With setting "nondir", only directories are protected by such events, other existing file types get treated with -rm before the new file gets added. Setting "on" allows automatic -rm_r. I.e. a non-directory can replace an existing directory and all its subordinates.
    If restoring of files is enabled, then the overwrite rule applies to the target file objects on disk as well, but "on" is downgraded to "nondir".

-split_size number["k"|"m"]
    Set the threshold for automatic splitting of regular files. Such splitting maps a large disk file onto a ISO directory with several part files in it. This is necessary if the size of the disk file exceeds -file_size_limit. Older operating systems can handle files in mounted ISO 9660 filesystems only if they are smaller than 2 GiB resp. 4 GiB.
    Default is 0 which will exclude files larger than -file_size_limit by a FAILURE event. A well tested -split_size is 2047m. Sizes above -file_size_limit are not permissible.
    While option -split_size is set larger than 0 such a directory with split file pieces will be recognized and handled like a regular file by options -compare* , -update*, and in overwrite situations. There are -ossirox options "concat_split_on" and "concat_split_off" which control the handling when files get restored to disk.
    In order to be recognizable, the names of the part files have to describe the splitting by 5 numbers:
     part_number,total_parts,byte_offset,byte_count,disk_file_size
    which are embedded in the following text form:
     part_#_of_#_at_#_with_#_of_#
    Scaling characters like "m" or "k" are taken into respect. All digits are interpreted as decimal, even if leading zeros are present.
    E.g: /file/part_1_of_3_at_0_with_2047m_of_5753194821
    No other files are allowed in the directory. All parts have to be present and their numbers have to be plausible. E.g. byte_count must be valid as -cut_out argument and their contents may not overlap.

File manipulations:

The following commands manipulate files in the ISO image, regardless whether they stem from the loaded image or were newly inserted.

-iso_rr_pattern "on"|"ls"|"off"
    Set the pattern expansion mode for the iso_rr_path arguments of several commands which support this feature.
    Setting "off" disables pattern expansion for all commands which are marked in this man page by "iso_rr_path [***]" or "iso_rr_pattern [***]".
    Setting "on" enables it for all those commands.
    Setting "ls" enables it only for those which are marked by "iso_rr_pattern [***]".
    Default is "on".

-rm iso_rr_path [***]
    Delete the given files from the ISO image.
    Note: This does not free any space on the -indev medium, even if the deletion is committed to that same medium.
    The image size will shrink if the image is written to a different medium in modification mode.

-rm_r iso_rr_path [***]
    Delete the given files or directory trees from the ISO image. See also the note with option -rm.

-rmdir iso_rr_path [***]
    Delete empty directories.

-mv iso_rr_path [***] iso_rr_path
    Rename the given file objects in the ISO tree to the last argument in the list. Use the same rules as with shell command mv.
    If pattern expansion is enabled and if the last argument contains wildcard characters then it must match exactly one existing file address, or else the command fails with a FAILURE event.

-chown uid iso_rr_path [***]
    Set ownership of file objects in the ISO image. uid may either be a decimal number or the name of a user known to the operating system.

-chown_r uid iso_rr_path [***]
    Like -chown but affecting all files below eventual directories.

-chgrp gid iso_rr_path [***]
    Set group attribute of file objects in the ISO image. gid may either be a decimal number or the name of a group known to the operating system.

-chgrp_r gid iso_rr_path [***]
    Like -chgrp but affecting all files below eventual directories.

-chmod mode iso_rr_path [***]
    Equivalent to shell command chmod in the ISO image. mode is either an octal number beginning with "0" or a comma separated list of statements of the form [ugoa]*[+-=][rwxst]* .
    Like: go-rwx,u+rwx .
    Personalities: u=user, g=group, o=others, a=all
    Operators: + adds given permissions, - revokes given permissions, = revokes all old permissions and then adds the given ones.
    Permissions: r=read, w=write, x=execute|inspect, s=setuid|setgid, t=sticky bit
    For octal numbers see man 2 stat.

-chmod_r mode iso_rr_path [***]
    Like -chmod but affecting all files below eventual directories.

-setfacl acl_text iso_rr_path [***]
    Attach the given ACL to the given iso_rr_paths. If the files already have ACLs, then those get deleted before the new ones get into effect. If acl_text is empty, or contains the text "clear" or the text "--remove-all", then the existing ACLs will be removed and no new ones will be attached. Any other content of acl_text will be interpreted as a list of ACL entries. It may be in the long multi-line format as put out by -getfacl but may also be abbreviated as follows:
    ACL entries are separated by comma or newline. If an entry is empty text or begins with "#" then it will be ignored. A valid entry has to begin by a letter out of {ugom} for "user", "group", "other", "mask". It has to contain two colons ":". A non-empty text between those ":" gives a user id resp. group id. After the second ":" there may be letters out of {rwx- #}. The first three give read, write resp. execute permission. Letters "-", " " and TAB are ignored. "#" causes the rest of the entry to be ignored. Letter "X" or any other letters are not supported. Examples:
      g:toolies:rw,u:lisa:rw,u:1001:rw,u::wr,g::r,o::r,m::rw
      group:toolies:rw-,user::rw-,group::r--,other::r--,mask::rw-
    A valid entry may be prefixed by "d", some following characters and ":". This indicates that the entry goes to the "default" ACL rather than to the "access" ACL. Example:
      u::rwx,g::rx,o::,d:u::rwx,d:g::rx,d:o::,d:u:lisa:rwx,d:m::rwx

-setfacl_r acl_text iso_rr_path [***]
    Like -setfacl but affecting all files below eventual directories.

-setfacl_list disk_path
    Read the output of -getfacl_r or shell command getfacl -R and apply it to the iso_rr_paths as given in lines beginning with "# file:". This will change ownership, group and ACL of the given files. If disk_path is "-" then lines are read from standard input. Line "@" ends the list, "@@@" aborts without changing the pending iso_rr_path.
    Since -getfacl and getfacl -R strip leading "/" from file paths, the setting of -cd does always matter.

-setfattr [-]name value iso_rr_path [***]
    Attach the given xattr pair of name and value to the given iso_rr_paths. If the given name is prefixed by "-", then the pair with that name gets removed from the xattr list. If name is "--remove-all" then all user namespace xattr of the given iso_rr_paths get deleted. In case of deletion, value must be an empty text.
    Only names from the user namespace are allowed. I.e. a name has to begin with "user.", like "user.x" or "user.whatever".
    Values and names undergo the normal input processing of xorriso. See also option -backslash_codes. Other than with option -setfattr_list, the byte value 0 cannot be expressed via -setfattr.

-setfattr_r [-]name value iso_rr_path [***]
    Like -setfattr but affecting all files below eventual directories.

-setfattr_list disk_path
    Read the output of -getfattr_r or shell command getfattr -Rd and apply it to the iso_rr_paths as given in lines beginning with "# file:". All previously existing user space xattr of the given iso_rr_paths will be deleted. If disk_path is "-" then lines are read from standard input.
    Since -getfattr and getfattr -Rd strip leading "/" from file paths, the setting of -cd does always matter.
    Empty input lines and lines which begin by "#" will be ignored (except "# file:"). Line "@" ends the list, "@@@" aborts without changing the pending iso_rr_path. Other input lines must have the form
      name="value"
    Name must be from user namespace. I.e. user.xyz where xyz should consist of printable characters only. The separator "=" is not allowed in names. Value may contain any kind of bytes. It must be in quotes. Trailing whitespace after the end quote will be ignored. Non-printables bytes and quotes must be represented as \XYZ by their octal ASCII code XYZ. Use code \000 for 0-bytes.

-alter_date type timestring iso_rr_path [***]
    Alter the date entries of a file in the ISO image. type is one of "a", "m", "b" for access time, modification time, both times.
    timestring may be in the following formats (see also section EXAMPLES):
    As expected by program date:
     MMDDhhmm[[CC]YY][.ss]]
    As produced by program date:
     [Day] MMM DD hh:mm:ss [TZON] YYYY
    Relative times counted from current clock time:
     +|-Number["s"|"h"|"d"|"w"|"m"|"y"]
    where "s" means seconds, "h" hours, "d" days, "w" weeks, "m"=30d, "y"=365.25d plus 1d added to multiplication result.
    Absolute seconds counted from Jan 1 1970:
     =Number
    xorriso's own timestamps:
     YYYY.MM.DD[.hh[mm[ss]]]
    scdbackup timestamps:
     YYMMDD[.hhmm[ss]]
    where "A0" is year 2000, "B0" is 2010, etc.

-alter_date_r type timestring iso_rr_path [***]
    Like -alter_date but affecting all files below eventual directories.

-hide hide_state iso_rr_path [***]
    Prevent the names of the given files from showing up in the directory trees of ISO 9660 and/or Joliet when the image gets written. 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.
    Warning: Data which are hidden from the ISO 9660 tree will not be copied by the write method of modifying.
    Possible values of hide_state are: "iso_rr" for hiding from ISO 9660 tree, "joliet" for Joliet tree, "on" for both trees. "off" means visibility in both directory trees.
    This command does not apply to the boot catalog. Rather use: -boot_image "any" "cat_hidden=on"

Tree traversal command -find:

-find iso_rr_path [test [op] [test ...]] [-exec action [params]] --
    A restricted substitute for shell command find in the ISO image. It performs an action on matching file objects at or below iso_rr_path.
    If not used as last command in the line then the argument list needs to get terminated by "--".
    Tests are optional. If they are omitted then action is applied to all file objects. If tests are given then they form together an expression. The action is applied only if the expression matches the file object. Default expression operator between tests is -and, i.e. the expression matches only if all its tests match.
    Available tests are:
    -name pattern : Matches if pattern matches the file leaf name.
    -wholename pattern : Matches if pattern matches the file path as it would be printed by action "echo". Character '/' is not special but can be matched by wildcards.
    -disk_name pattern : Like -name but testing the leaf name of the file source on disk. Can be true only for data files which stem not from the loaded image.
    -type type_letter : Matches files of the given type: "block", "char", "dir", "pipe", "file", "link", "socket", "eltorito", and "Xotic" which matches what is not matched by the other types.
    Only the first letter is interpreted. E.g.: -find / -type d
    -damaged : Matches files which use data blocks marked as damaged by a previous run of -check_media. The damage info vanishes when a new ISO image gets loaded.
    Note that a MD5 session mismatch marks all files of the session as damaged. If finer distinction is desired, perform -md5 off before -check_media.
    -pending_data : Matches files which get their content from outside the loaded ISO image.
    -lba_range start_lba block_count : Matches files which use data blocks within the range of start_lba and start_lba+block_count-1.
    -has_acl : Matches files which have a non-trivial ACL.
    -has_xattr : Matches files which have xattr name-value pairs from user namespace.
    -has_aaip : Matches files which have ACL or any xattr.
    -has_any_xattr : Matches files which have any xattr other than ACL.
    -has_md5 : Matches data files which have MD5 checksums.
    -has_filter : Matches files which are filtered by -set_filter.
    -hidden hide_state : Matches files which are hidden in "iso_rr" tree, in "joliet" tree, in both trees ("on"), or not hidden in any tree ("off"). Those which are hidden in some tree match -not -hidden "off".
    -prune : If this test is reached and the tested file is a directory then -find will not dive into that directory. This test itself does always match.
    -decision "yes"|"no" : If this test is reached then the evaluation ends immediately and action is performed if the decision is "yes" or "true". See operator -if.
    -true and -false : Always match resp. match not. Evaluation goes on.
    -sort_lba : Always match. This causes -find to perform its action in a sequence sorted by the ISO image block addresses of the files. It may improve throughput with actions which read data from optical drives. Action will always get the absolute path as parameter.
    Available operators are:
    -not : Matches if the next test or sub expression does not match. Several tests do this specifically:
    -undamaged, -lba_range with negative start_lba, -has_no_acl, -has_no_xattr, -has_no_aaip, -has_no_filter .
    -and : Matches if both neighboring tests or expressions match.
    -or : Matches if at least one of both neighboring tests or expressions matches.
    -sub ... -subend or ( ... ) : Enclose a sub expression which gets evaluated first before it is processed by neighboring operators. Normal precedence is: -not, -or , -and.
    -if ... -then ... -elseif ... -then ... -else ... -endif : Enclose one or more sub expressions. If the -if expression matches, then the -then expression is evaluated as the result of the whole expression up to -endif. Else the next -elseif expression is evaluated and if it matches, its -then expression. Finally in case of no match, the -else expression is evaluated. There may be more than one -elseif. Neither -else nor -elseif are mandatory. If -else is missing and would be hit, then the result is a non-match.
    -if-expressions are the main use case for above test -decision. Default action is echo, i.e. to print the address of the found file. Other actions are certain xorriso commands which get performed on the found files. These commands may have specific parameters. See also their particular descriptions.
    chown and chown_r change the ownership and get the user id as parameter. E.g.: -exec chown thomas --
    chgrp and chgrp_r change the group attribute and get the group id as parameter. E.g.: -exec chgrp_r staff --
    chmod and chmod_r change access permissions and get a mode string as parameter. E.g.: -exec chmod a-w,a+r --
    alter_date and alter_date_r change the timestamps. They get a type character and a timestring as parameters.
    E.g.: -exec alter_date "m" "Dec 30 19:34:12 2007" --
    lsdl prints file information like shell command ls -dl.
    compare performs command -compare with the found file address as iso_rr_path and the corresponding file address below its argument disk_path_start. For this the iso_rr_path of the -find command gets replaced by the disk_path_start.
    E.g.: -find /thomas -exec compare /home/thomas --
    update performs command -update with the found file address as iso_rr_path. The corresponding file address is determined like with above action "compare".
    update_merge is like update but does not delete the found file if it is missing on disk. It may be run several times and records with all visited files whether their counterpart on disk has already been seen by one of the update_merge runs. Finally, a -find run with action "rm_merge" may remove all files that saw no counterpart on disk.
    Up to the next "rm_merge" or "clear_merge" all newly inserted files will get marked as having a disk counterpart.
    rm removes the found iso_rr_path from the image if it is not a directory with files in it. I.e. this "rm" includes "rmdir".
    rm_r removes the found iso_rr_path from the image, including whole directory trees.
    rm_merge removes the found iso_rr_path if it was visited by one or more previous actions "update_merge" and saw no counterpart on disk in any of them. The marking from the update actions is removed in any case.
    clear_merge removes an eventual marking from action "update_merge".
    report_damage classifies files whether they hit a data block that is marked as damaged. The result is printed together with the address of the first damaged byte, the maximum span of damages, file size, and the path of the file.
    report_lba prints files which are associated to image data blocks. It tells the logical block address, the block number, the byte size, and the path of each file. There may be reported more than one line per file if the file is very large. In this case each line has a different extent number in column "xt".
    getfacl prints access permissions in ACL text form to the result channel.
    setfacl attaches ACLs after removing existing ones. The new ACL is given in text form as defined with option -setfacl.
    E.g.: -exec setfacl u:lisa:rw,u::rw,g::r,o::-,m::rw --
    getfattr prints xattr name-value pairs from user namespace to the result channel.
    get_any_xattr prints xattr name-value pairs from any namespace except ACL to the result channel. This is mostly for debugging of namespace "isofs".
    list_extattr mode prints a script to the result channel, which would use FreeBSD command setextattr to set the file's xattr name-value pairs of user namespace. Parameter mode controls the form of the output of names and values. Default mode "e" prints harmless characters in shell quotation marks, but represents texts with octal 001 to 037 and 0177 to 0377 by an embedded echo -e command. Mode "q" prints any characters in shell quotation marks. This might not be terminal-safe but should work in script files. Mode "r" uses no quotation marks. Not safe. Mode "b" prints backslash encoding. Not suitable for shell parsing.
    E.g. -exec list_extattr e --
    Option -backslash_codes does not affect the output.
    get_md5 prints the MD5 sum, if recorded, together with file path.
    check_md5 compares the MD5 sum, if recorded, with the file content and reports if mismatch.
    E.g.: -find / -not -pending_data -exec check_md5 FAILURE --
    make_md5 equips a data file with an MD5 sum of its content. Useful to upgrade the files in the loaded image to full MD5 coverage by the next commit with -md5 "on".
    E.g.: -find / -type f -not -has_md5 -exec make_md5 --
    setfattr sets or deletes xattr name value pairs.
    E.g.: -find / -has_xattr -exec setfattr --remove-all '' --
    set_filter applies or removes filters.
    E.g.: -exec set_filter --zisofs --
    mkisofs_r applies the rules of mkisofs -r to the file object:
    user id and group id become 0, all r-permissions get granted, all w denied. If there is any x-permission, then all three x get granted. s- and t-bits get removed.
    sort_weight attributes a LBA weight number to regular files.
    The 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 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.
    E.g.: -exec sort_weight 3 --
    show_stream shows the content stream chain of a data file.
    hide brings the file into one of the hide states "on", "iso_rr", "joliet", "off".
    E.g.:
      -find / -disk_name *_secret -exec hide on
    estimate_size prints a lower and an upper estimation of the number of blocks which the found files together will occupy in the emerging ISO image. This does not account for the superblock, for the directories in the -find path, or for image padding.
    find performs another run of -find on the matching file address. It accepts the same params as -find, except iso_rr_path.
    E.g.:
      -find / -name '???' -type d -exec find -name '[abc]*' -exec chmod a-w,a+r --

Filters for data file content:

Filters may be installed between data files in the ISO image and their content source outside the image. They may also be used vice versa between data content in the image and target files on disk.
Built-in filters are "--zisofs" and "--zisofs-decode". The former is to be applied via -set_filter, the latter is automatically applied if zisofs compressed content is detected with a file when loading the ISO image.
Another built-in filter pair is "--gzip" and "--gunzip" with suffix ".gz". They behave about like external gzip and gunzip but avoid forking a process for each single file. So they are much faster if there are many small files.

-external_filter name option[:option] program_path [arguments] --
    Register a content filter by associating a name with a program path, program arguments, and some behavioral options. Once registered it can be applied to multiple data files in the ISO image, regardless whether their content resides in the loaded ISO image or in the local filesystem. External filter processes may produce synthetic file content by reading the original content from stdin and writing to stdout whatever they want. They must deliver the same output on the same input in repeated runs.
    Options are:
     "default" means that no other option is intended.
     "suffix=..." sets a file name suffix. If it is not empty then it will be appended to the file name or removed from it.
     "remove_suffix" will remove a file name suffix rather than appending it.
     "if_nonempty" will leave 0-sized files unfiltered.
     "if_reduction" will try filtering and revoke it if the content size does not shrink.
     "if_block_reduction" will revoke if the number of 2 kB blocks does not shrink.
     "used=..." is ignored. Command -status shows it with the number of files which currently have the filter applied.
    Examples:
     -external_filter bzip2 suffix=.bz2:if_block_reduction \
                      /usr/bin/bzip2 --
     -external_filter bunzip2 suffix=.bz2:remove_suffix \
                      /usr/bin/bunzip2 --

-unregister_filter name
    Remove an -external_filter registration. This is only possible if the filter is not applied to any file in the ISO image.

-close_filter_list
    Irrevocably ban commands -external_filter and -unregister_filter, but not -set_filter. Use this to prevent external filtering in general or when all intended filters are registered. External filters may also be banned totally at compile time of xorriso. By default they are banned if xorriso runs under setuid permission.

-set_filter name iso_rr_path [***]
    Apply an -external_filter or a built-in filter to the given data files in the ISO image. If the filter suffix is not empty , then it will be applied to the file name. Renaming only happens if the filter really gets attached and is not revoked by its options. By default files which already bear the suffix will not get filtered. The others will get the suffix appended to their names. If the filter has option "remove_suffix", then the filter will only be applied if the suffix is present and can be removed. Name oversize or collision caused by suffix change will prevent filtering.
    With most filter types this command will immediately run the filter once for each file in order to determine the output size. Content reading operations like -extract , -compare and image generation will perform further filter runs and deliver filtered content.
    At image generation time the filter output must still be the same as the output from the first run. Filtering for image generation does not happen with files from the loaded ISO image if the write method of growing is in effect (i.e -indev and -outdev are identical).
    The reserved filter name "--remove-all-filters" revokes filtering. This will revoke suffix renamings as well. Use "--remove-all-filters+" to prevent any suffix renaming.

-set_filter_r name iso_rr_path [***]
    Like -set_filter but affecting all data files below eventual directories.

Writing the result, drive control:

(see also paragraph about settings below)

-rollback
    Discard the manipulated ISO image and reload it from -indev. (Use -rollback_end if immediate program end is desired.)

-commit
    Perform the write operation. Afterwards, if -outdev is readable, make it the new -dev and load the image from there. Switch to growing mode. (A subsequent -outdev will activate modification mode or blind growing.) -commit is performed automatically at end of program if there are uncommitted manipulations pending.
    So, to perform a final write operation with no new -dev and no new loading of image, rather execute option -end. If you want to go on without image loading, execute -commit_eject "none". To eject after write without image loading, use -commit_eject "all".
    To suppress a final write, execute -rollback_end.
    Writing can last quite a while. It is not unnormal with several types of media that there is no progress visible for the first few minutes or that the drive gnaws on the medium for a few minutes after all data have been transmitted. xorriso and the drives are in a client-server relationship. The drives have much freedom about what to do with the media. Some combinations of drives and media simply do not work, despite the promises by their vendors. If writing fails then try other media or another drive. The reason for such failure is hardly ever in the code of the various burn programs but you may well try some of those listed below under SEE ALSO.

-eject "in"|"out"|"all"
    Eject the medium in -indev, resp. -outdev, resp. both drives. Note: It is not possible yet to effectively eject disk files.

-commit_eject "in"|"out"|"all"|"none"
    Combined -commit and -eject. When writing has finished do not make -outdev the new -dev, and load no ISO image. Rather eject -indev and/or -outdev. Give up any non-ejected drive.

-blank mode
    Make media ready for writing from scratch (if not -dummy is activated).
    This affects only the -outdev not the -indev. If both drives are the same and if the ISO image was altered then this command leads to a FAILURE event. Defined modes are:
      as_needed, fast, all, deformat, deformat_quickest
    "as_needed" cares for used CD-RW, DVD-RW and for used overwriteable media by applying -blank "fast". It applies -format "full" to yet unformatted DVD-RAM and BD-RE. Other media in blank state are gracefully ignored. Media which cannot be made ready for writing from scratch cause a FAILURE event.
    "fast" makes CD-RW and unformatted DVD-RW re-usable, or invalidates overwriteable ISO images. "all" might work more thoroughly and need more time.
    "deformat" converts overwriteable DVD-RW into unformatted ones.
    "deformat_quickest" is a faster way to deformat or blank DVD-RW but produces media which are only suitable for a single session. Some drives announce this state by not offering feature 21h, but some drives offer it anyway. If feature 21h is missing, then xorriso will refuse to write on DVD-RW if not option -close is set to "on".
    The progress reports issued by some drives while blanking are quite unrealistic. Do not conclude success or failure from the reported percentages. Blanking was successful if no SORRY event or worse occured.

-format mode
    Convert unformatted DVD-RW into overwriteable ones, "de-ice" DVD+RW, format newly purchased BD-RE or BD-R, re-format DVD-RAM or BD-RE.
    Defined modes are:
      as_needed, full, fast, by_index_<num>, fast_by_index_<num>
    "as_needed" formats yet unformatted DVD-RW, DVD-RAM, BD-RE, or blank unformatted BD-R. Other media are left untouched.
    "full" (re-)formats DVD-RW, DVD+RW, DVD-RAM, BD-RE, or blank unformatted BD-R.
    "fast" does the same as "full" but tries to be quicker.
    "by_index_" selects a format out of the descriptor list issued by option -list_formats. The index number from that list is to be appended to the mode word. E.g: "by_index_3".
    "fast_by_index_" does the same as "by_index_" but tries to be quicker.
    "by_size_" selects a format out of the descriptor list which provides at least the given size. That size is to be appended to the mode word. E.g: "by_size_4100m". This applies to media with Defect Management.
    "fast_by_size_" does the same as "by_size_" but tries to be quicker.
    The formatting action has no effect on media if -dummy is activated.
    Formatting is normally needed only once during the lifetime of a medium, if ever. But it is a reason for re-formatting if:
     DVD-RW was deformatted by -blank,
     DVD+RW has read failures (re-format before next write),
     DVD-RAM or BD-RE shall change their amount of defect reserve.
    BD-R may be written unformatted or may be formatted before first use. Formatting activates Defect Management which tries to catch and repair bad spots on media during the write process at the expense of half speed even with flawless media.
    The progress reports issued by some drives while formatting are quite unrealistic. Do not conclude success or failure from the reported percentages. Formatting was successful if no SORRY event or worse occured. Be patient with apparently frozen progress.

-list_formats
    Put out a list of format descriptors as reported by the output drive for the current medium. The list gives the index number after "Format idx", a MMC format code, the announced size in blocks (like "2236704s") and the same size in MiB.
    MMC format codes are manifold. Most important are: "00h" general formatting, "01h" increases reserve space for DVD-RAM, "26h" for DVD+RW, "30h" for BD-RE with reserve space, "31h" for BD-RE without reserve space, "32h" for BD-R.
    Smaller format size with DVD-RAM, BD-RE, or BD-R means more reserve space.

-list_speeds
    Put out a list of speed values as reported by the output drive with the loaded medium. This does not necessarily mean that the medium is writable or that these speeds are actually achievable. Especially the lists reported with empty drive or with ROM media obviously advertise speeds for other media.
    It is not mandatory to use speed values out of the listed range. The drive is supposed to choose a safe speed that is as near to the desired speed as possible.
    At the end of the list, "Write speed L" and "Write speed H" are the best guesses for lower and upper speed limit. "Write speed l" and "Write speed h" may appear only with CD and eventually override the list of other speed offers.

-close_damaged "as_needed"|"force"
    Try to close the upcomming track and session if the drive reported the medium as damaged. This may apply to CD-R, CD-RW, DVD-R, DVD-RW, DVD+R, DVD+R DL, or BD-R media. It is indicated by warning messages when the drive gets aquired, and by a remark "but next track is damaged" with the line "Media status :" of command -toc.
    The setting of option -close determines whether the medium stays appendable.
    Mode "as_needed" gracefully refuses on media which are not reported as damaged. Mode "force" attempts the close operation even with media which appear undamaged.
    No image changes are allowed to be pending before this command is performed. After closing was attempted, both drives are given up.

-list_profiles "in"|"out"|"all"
    Put out a list of media types supported by -indev, resp. -outdev, resp. both. The currently recognized type is marked by text "(current)".

Settings for result writing:

Rock Ridge info will be generated by the program unconditionally. ACLs will be written according to the setting of option -acl.

-joliet "on"|"off"
    If enabled by "on", generate Joliet tree additional to ISO 9660 + Rock Ridge tree.

-compliance rule[:rule...]
    Adjust the compliance to specifications of ISO 9660 and its contemporary extensions. In some cases it is worth to deviate a bit in order to circumvent bugs of the intended reader system or to get unofficial extra features.
    There are several adjustable rules which have a keyword each. If they are mentioned with this option then their rule gets added to the relaxation list. This list can be erased by rules "strict" or "clear". It can be reset to its start setting by "default". All of the following relaxation rules can be revoked individually by appending "_off". Like "deep_paths_off".
    Rule keywords are:
    "iso_9660_level="number chooses level 1 with ISO names of the form 8.3 and -file_size_limit <= 4g - 1, or level 2 with ISO names up to length 32 and the same -file_size_limit, or level 3 with ISO names up to length 32 and -file_size_limit >= 400g -200k. If necessary -file_size_limit gets adjusted.
    "allow_dir_id_ext" allows ISO names of directories to have a name extension as with other file types. It does not force dots and it omits the version number, though. This is a bad tradition of mkisofs which violates ECMA-119. Especially ISO level 1 only allows 8 characters in a directory name and not 8.3.
    "omit_version" does not add versions (";1") to ISO and Joliet file names.
    "only_iso_version" does not add versions (";1") to Joliet file names.
    "deep_paths" allows ISO file paths deeper than 8 levels.
    "long_paths" allows ISO file paths longer than 255 characters.
    "long_names" allows up to 37 characters with ISO file names.
    "no_force_dots" does not add a dot to ISO file names which have none.
    "no_j_force_dots" does not add a dot to Joliet file names which have none.
    "lowercase" allows lowercase characters in ISO file names.
    "full_ascii" allows all ASCII characters in ISO file names.
    "untranslated_names" might be dangerous for inadverted reader programs which rely on the restriction to at most 37 characters in ISO file names. This option allows ISO file names up to 96 characters with no character conversion. If a file name has more characters, then image production will fail deliberately.
    "untranslated_name_len="number enables untranslated_names with a smaller limit for the length of file names. 0 disables this feature, -1 chooses maximum length limit, numbers larger than 0 give the desired length limit.
    "joliet_long_names" allows Joliet leaf names up to 103 characters rather than 64.
    "joliet_long_paths" allows Joliet paths longer than 240 characters.
    "always_gmt" stores timestamps in GMT representation with timezone 0.
    "rec_mtime" records with non-RockRidge directory entries the disk file's mtime and not the creation time of the image. This applies to the ECMA-119 tree (plain ISO 9660), to Joliet, and to ISO 9660:1999. "rec_time" is default. If disabled, it gets automatically re-enabled by -as mkisofs emulation when a pathspec is encountered.
    "new_rr" uses Rock Ridge version 1.12 (suitable for GNU/Linux but not for older FreeBSD or for Solaris). This implies "aaip_susp_1_10_off" which may be changed by subsequent "aaip_susp_1_10".
    Default is "old_rr" which uses Rock Ridge version 1.10. This implies also "aaip_susp_1_10" which may be changed by subsequent "aaip_susp_1_10_off".
    "aaip_susp_1_10" allows AAIP to be written as unofficial extension of RRIP rather than as official extension under SUSP-1.12.
    "no_emul_toc" saves 64 kB with the first session on overwriteable media but makes the image incapable of displaying its session history.
    "iso_9660_1999" causes the production of an additional directory tree compliant to ISO 9660:1999. It can record long filenames for readers which do not understand Rock Ridge.
    "old_empty" uses 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.
    Default setting is
     "clear:only_iso_version:deep_paths:long_paths:no_j_force_dots:
     always_gmt:old_rr".
    Note: The term "ISO file" means the plain ISO 9660 names and attributes which get visible if the reader ignores Rock Ridge.

-volid text
    Specify the volume ID. xorriso accepts any text up to 32 characters, but according to rarely obeyed specs stricter rules apply:
    ECMA 119 demands 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.
    If an ISO image gets loaded while the volume ID is set to default "ISOIMAGE" or to "", then the volume ID of the loaded image will become the effective volume id for the next write run. But as soon as command -volid is performed afterwards, this pending id is overridden by the new setting.
    Consider this when setting -volid "ISOIMAGE" before executing -dev, -indev, or -rollback. If you insist in -volid "ISOIMAGE", set it again after those commands.

-volset_id text
    Set the volume set id string to be written with the next -commit. Permissible are up to 128 characters. This setting gets overridden by image loading.

-publisher text
    Set the publisher id string to be written with the next -commit. This may identify the person or organisation who specified what shall be recorded. Permissible are up to 128 characters. This setting gets overridden by image loading.

-application_id text
    Set the application id string to be written with the next -commit. This may identify the specification of how the data are recorded. Permissible are up to 128 characters. This setting gets overridden by image loading.
    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.

-system_id text
    Set the system id string to be written with the next -commit. 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. This setting gets overridden by image loading.

-volume_date type timestring
    Set one of the four overall timestamps for subsequent image writing. Available types are:
    "c" time when the volume was created.
    "m" time when volume was last modified.
    "x" time when the information in the volume expires.
    "f" time since when the volume is effectively valid.
    "uuid" sets a timestring that overrides "c" and "m" times 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).
    Timestrings for the other types may be given as with option -alter_date. They are prone to timezone computations. The timestrings "default" or "overridden" cause default settings: "c" and "m" will show the current time of image creation. "x" and "f" will be marked as insignificant. "uuid" will be deactivated.

-copyright_file text
    Set the copyright file name to be written with the next -commit. This should be the ISO 9660 path of a file in the image which contains a copyright statement. Permissible are up to 37 characters. This setting gets overridden by image loading.

-abstract_file text
    Set the abstract file name to be written with the next -commit. 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. This setting gets overridden by image loading.

-biblio_file text
    Set the biblio file name to be written with the next -commit. This should be the ISO 9660 path of a file in the image which contains bibliographic records. Permissible are up to 37 characters. This setting gets overridden by image loading.

-preparer_id
    Set the preparer id string to be written with the next -commit. 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.
    Unlike other id strings, this setting is not influenced by image loading.

-out_charset character_set_name
    Set the character set to which file names get converted when writing an image. See paragraph "Character sets" for more explanations. When loading the written image after -commit the setting of -out_charset will be copied to -in_charset.

-uid uid
    User id to be used for all files when the new ISO tree gets written to media.

-gid gid
    Group id to be used for all files when the new ISO tree gets written to media.

-zisofs option[:options]
    Set global parameters for zisofs compression. This data format is recognized and transparently uncompressed by some Linux kernels. It is to be applied via option -set_filter with built-in filter "--zisofs". Parameters are:
     "level="[0-9] zlib compression: 0=none, 1=fast,..., 9=slow
     "block_size="32k|64k|128k size of compression blocks
     "by_magic=on" enables an expensive test at image generation time which checks files from disk whether they already are zisofs compressed, e.g. by program mkzftree.
     "default" same as "level=6:block_size=32k:by_magic=off"

-speed number[k|m|c|d|b]
    Set the burn speed. Default is 0 = maximum speed. Speed can be given in media dependent numbers or as a desired throughput per second in MMC compliant kB (= 1000) or MB (= 1000 kB). Media x-speed factor can be set explicity by "c" for CD, "d" for DVD, "b" for BD, "x" is optional.
    Example speeds:
     706k = 706kB/s = 4c = 4xCD
     5540k = 5540kB/s = 4d = 4xDVD
    If there is no hint about the speed unit attached, then the medium in the -outdev will decide. Default unit is CD = 176.4k.
    MMC drives usually activate their own idea of speed and take the speed value given by the burn program only as upper limit for their own decision.

-stream_recording "on"|"off"|"full"|"data"|number
    Setting "on" tries to circumvent the management of defects on DVD-RAM, BD-RE, or BD-R. Defect management keeps partly damaged media usable. But it reduces write speed to half nominal speed even if the medium is in perfect shape. For the case of flawless media, one may use -stream_recording "on" to get full speed.
    "full" tries full speed with all write operations, whereas "on" does this only above byte address 32s. One may give a number of at least 16s in order to set an own address limit.
    "data" causes full speed to start when superblock and directory entries are written and writing of file content blocks begins.

-dvd_obs "default"|"32k"|"64k"
    GNU/Linux specific: Set the number of bytes to be transmitted with each write operation to DVD or BD media. A number of 64 KB may improve throughput with bus systems which show latency problems. The default depends on media type, on option -stream_recording , and on compile time options.

-stdio_sync "on"|"off"|number
    Set the number of bytes after which to force output to stdio: pseudo drives. This forcing keeps the memory from being clogged with lots of pending data for slow devices. Default "on" is the same as "16m". Forced output can be disabled by "off".

-dummy "on"|"off"
    If "on" then simulate burning or refuse with FAILURE event if no simulation is possible, do neither blank nor format.

-fs number["k"|"m"]
    Set the size of the fifo buffer which smoothens the data stream from ISO image generation to media burning. Default is 4 MiB, minimum 64 kiB, maximum 1 GiB. The number may be followed by letter "k" or "m" which means unit is kiB (= 1024) or MiB (= 1024 kiB).

-close "on"|"off"
    If "on" then mark the written medium as not appendable any more (if possible at all with the given type of target media).
    This is the contrary of cdrecord, wodim, cdrskin option -multi, and is one aspect of growisofs option -dvd-compat.

-padding number["k"|"m"]|"included"|"appended"
    Append the given number of extra bytes to the image stream. This is a traditional remedy for a traditional bug in block device read drivers. Needed only for CD recordings in TAO mode. Since one can hardly predict on what media an image might end up, xorriso adds the traditional 300k of padding by default to all images.
    For images which will never get to a CD it is safe to use -padding 0 .
    Normally padding is not written as part of the ISO image but appended after the image end. This is -padding mode "appended".
    Emulation command -as "mkisofs" and command -jigdo cause padding to be written as part of the image. The same effect is achieved by -padding mode "included".

Bootable ISO images:

Contrary to published specifications many BIOSes will load an El Torito record from the first session on media and not from the last one, which gets mounted by default. This makes no problems with overwriteable media, because they appear to inadverted readers as one single session.
But with multi-session media CD-R[W], DVD-R[W], DVD+R, it implies that the whole bootable system has to reside already in the first session and that the last session still has to bear all files which the booted system expects after mounting the ISO image.
If a boot image from ISOLINUX or GRUB is known to be present on media then it is advised to patch it when a follow-up session gets written. But one should not rely on the capability to influence the bootability of the existing sessions, unless one can assume overwriteable media.
There are booting mechanisms which do not use an El Torito record but rather start at the first bytes of the image: PC-BIOS MBR for hard-disk-like devices, MIPS Volume Header for old SGI computers, DEC Boot Block for old DECstation, SUN Disk Label for SPARC machines.
The boot firmware EFI may use programs which are located in a FAT filesystem and announced by an MBR partition table entry.

-boot_image "any"|"isolinux"|"grub"
         "discard"|"keep"|"patch"|"show_status"|bootspec|"next"
    Define the handling of a set of El Torito boot images which has been read from an existing ISO image or define how to make a prepared boot image file set bootable. Such file sets get produced by ISOLINUX or GRUB.
    Each -boot_image command has two arguments: type and setting. More than one -boot_image command may be used to define the handling of one or more boot images. Sequence matters.
    Types isolinux and grub care for known peculiarities. Type any makes no assumptions about the origin of the boot images.
    El Torito boot images of any type can be newly inserted, or discarded, or patched, or kept unaltered. Whether to patch or to keep depends on whether the boot images contain boot info tables.
    A boot info table needs to be patched when the boot image gets newly introduced into the ISO image or if an existing image gets relocated. This is automatically done if type "isolinux" or "grub" is given, but not with "any".
    If patching is enabled, then boot images from previous sessions will be checked whether they seem to bear a boot info table. If not, then they stay unpatched. This check is not infallible. So if you do know that the images need no patching, use "any" "keep". "grub" "patch" will not patch EFI images (platform_id=0xef).
    Most safe is the default: -boot_image "any" "discard".
    Advised for GRUB : -boot_image "grub" "patch"
    For ISOLINUX : -boot_image "isolinux" "patch"
    show_status will print what is known about the loaded boot images and their designated fate.
    A bootspec is a word of the form name=valuei. It is used to describe the parameters of a boot image by an El Torito record or a MBR. The names "dir", "bin_path", "efi_path" lead to El Torito bootable images. Name "system_area" activates a given file as MBR.
    On all media types this is possible within the first session. In further sessions an existing boot image can get replaced by a new one, but depending on the media type this may have few effect at boot time. See above.
    The boot image and its supporting files have to be added to the ISO image by normal means (image loading, -map, -add, ...). In case of ISOLINUX the files should reside either in ISO image directory /isolinux or in /boot/isolinux . In that case it suffices to use as bootspec the text "dir=/isolinux" or "dir=/boot/isolinux". E.g.:
     -boot_image isolinux dir=/boot/isolinux
    which bundles these individual settings:
     -boot_image isolinux bin_path=/boot/isolinux/isolinux.bin
     -boot_image isolinux cat_path=/boot/isolinux/boot.cat
     -boot_image isolinux load_size=2048
     -boot_image any boot_info_table=on
    An El Torito boot catalog file gets inserted into the ISO image with address cat_path= at -commit time. It is subject to normal -overwrite and -reassure processing if there is already a file with the same name. The catalog lists the boot images and is read by the boot facility to choose one of the boot images. But it is not necessary that it appears in the directory tree at all. One may hide it in all trees by cat_hidden=on. Other possible values are "iso_rr", "joliet", and the default "off".
    bin_path= depicts a boot image file, a binary program which is to be started by the hardware boot facility (e.g. the BIOS) at boot time.
    efi_path= depicts a boot image file that is ready for EFI booting. Its load_size is determined automatically, no boot info table gets written, no boot medium gets emulated, platform_id is 0xef.
    emul_type= can be one of "no_emulation", "hard_disk", "diskette". It controls the boot medium emulation code of a boot image. The default "no_emulation" is suitable for ISOLINUX, GRUB, FreeBSD cdboot.
    load_size= is a value which depends on the boot image. Default 2048 should be overridden only if a better value is known.
    boot_info_table=on may be used to apply patching to a boot image which is given by "any" "bin_path=". "boot_info_table=off" disables patching.
    platform_id= defines by two hex digits the Platform ID of the boot image. "00" is 80x86 PC-BIOS, "01" is PowerPC, "02" is Mac, "ef" is EFI.
    id_string=text|56_hexdigits defines 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.
    sel_crit=hexdigits defines 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.
    next ends the definition of a boot image and starts a new one. Any following -bootimage bootspecs will affect the new image. The first "next" discards loaded boot images and their catalog.
    discard gives up an existing boot catalog and its boot images.
    keep keeps or copies boot images unaltered and writes a new catalog.
    patch applies patching to existing boot images if they seem to bear a boot info table.
    system_area=disk_path copies at most 32768 bytes from the given disk file to the very start of the ISO image. This System Area is reserved for system dependent boot software, e.g. an MBR which can be used to boot from USB stick or hard disk.
    Other than a El Torito boot image, the file disk_path needs not to be added to the ISO image.
    -boot_image isolinux system_area= implies "partition_table=on".
    partition_table=on causes a simple partition table to be written into bytes 446 to 511 of the System Area.
    With type "isolinux" it shows a partition that begins at byte 0 and it causes the LBA of the first boot image to be written into the MBR. For the first session this works only if also "system_area=" and "bin_path=" or "dir=" is given.
    With types "any" and "grub" it shows a single partiton which starts at byte 512 and ends where the ISO image ends. This works with or without system_area= or boot image.
    In follow-up sessions the existing System Area is preserved by default. If types "isolinux" or "grub" are set to "patch", then "partition_table=on" is activated without new boot image. In this case the existing System Area gets checked whether it bears addresses and sizes as if it had been processed by "partition_table=on". If so, then those parameters get updated when the new System Area is written.
    Special "system_area=/dev/zero" causes 32k of NUL-bytes. Use this to discard an MBR which was loaded with the ISO image.
    partition_offset=2kb_block_adr causes 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. 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. So the value defined here is only in effect if a new ISO image gets written.
    partition_hd_cyl=number gives the number of heads per cylinder for the partition table. 0 chooses a default value. Maximum is 255.
    partition_sec_hd=number gives the number of sectors per head for the 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 allow exact alignment. If it is too small to describe the image size by at most 1024 cylinders, 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.
    partition_cyl_align=mode controls 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.
    Mode "auto" is default. Alignment by padding happens only with "isolinux" "partition_table=on".
    Mode "on" causes alignment by padding with "partition_table=on" for any type. Mode "off" disables alignment for any type.
    mips_path=iso_rr_path declares a data file in the image to be a MIPS Big Endian boot file and causes 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 system_area=. Up to 15 boot files can be declared by mips_path=.
    mipsel_path=iso_rr_path declares 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 system_area=. Only a single boot file can be declared by mipsel_path=.
    sparc_label=text causes the production of a SUN Disk Label with the given text as ASCII label. This boot block format allows to append images for partitions 2 to 8. Partition 1 will always be the ISO image. See option -append_partition. The first 512 bytes of any data provided by system_area= will be overwritten.
    mips_discard and sparc_discard revoke any boot file declarations made by mips_path= or mipsel_path=. They also disable production of SUN Disk Label. This removes the ban on production of other boot blocks.

-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.
    Beware of subsequent multi-session runs. The appended partition will get overwritten.
    Partitions may be appended with boot block type MBR and with SUN Disk Label.
    With MBR:
    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 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".
    The disk_path must provide the necessary data bytes at commit time. An empty disk_path disables this feature for the given partition number.
    With SUN Disk Label (selected by -boot_image any sparc_label=):
    partition_number may be 2 to 8. Number 1 will always be the ISO image. Partition start addresses are aligned to 320 KiB. The type_code does not matter. Submit 0x0.
    Partition image name "." causes the partition to become a copy of the next lower valid one.

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."
xorriso can produce a .jigdo and a .template file together with a single-session ISO image. 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 xorriso session on a blank -outdev, and a .md5 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 .md5 file by a single text line:
MD5 as 32 hex digits, 2 blanks, size as 12 decimal digits or blanks, 2 blanks, symbolic file address
The file address in an .md5 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 xorriso will refuse to write to non-blank targets, it will disable multi-session emulation, and padding will be counted as part of the ISO image.

-jigdo parameter_name value
    Clear Jigdo Template Extraction parameter list or add a parameter to that list. The alias names are the corresponding genisoimage options. They are accepted as parameter names as well. Especially they are recognized by the -as mkisofs emulation command.
    Parameter clear with any value empties the whole list. No .jigdo and .template file will be produced.
    template_path sets the disk_path for the .template file with the holed and compressed ISO image copy.
    Alias: -jigdo-template
    jigdo_path sets the disk_path for the .jigdo file with the checksums and download addresses for filling the holes in .template.
    Alias: -jigdo-jigdo
    md5_path sets the disk_path where to find the .md5 input file.
    Alias: -md5-list
    min_size sets the minimum size for a data file to be listed in the .jigdo file and being a hole in the .template file.
    Alias: -jigdo-min-file-size
    exclude adds 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.
    Alias: -jigdo-exclude
    demand_md5 adds a regular expression pattern which will get compared with the absolute disk_path of any data file that was not found in the .md5 list. A match causes a MISHAP event.
    Alias: -jigdo-force-md5
    mapping adds 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 .md5 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.
    Alias: -jigdo-map
    compression chooses one of "bzip2" or "gzip" for the compression of the template file. The jigdo file is put out uncompressed.
    Alias: -jigdo-template-compress
    checksum_iso chooses one or more of "md5", "sha1", "sha256", "sha512" for the auxiliary "# Image Hex" checksums in the jigdo file. The value may e.g. look like "md5,sha1,sha512". Value "all" chooses all available algorithms. Note that MD5 stays always enabled.
    Alias: -checksum_algorithm_iso
    checksum_template is like checksum_iso but for "# Template Hex".
    Alias: -checksum_algorithm_template

Character sets:

File names are strings of non-zero bytes with 8 bit each. Unfortunately the same byte string may appear as different peculiar national characters on differently nationalized terminals. The meanings of byte codes are defined in character sets which have names. Shell command iconv -l lists them.
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 media use the same character set. Outside these constraints it may be necessary to let xorriso convert byte codes.
There is an input conversion from input character set to the local character set which applies when an ISO image gets loaded. A conversion from local character set to the output character set is performed when an image tree gets written. The sets can be defined independently by options -in_charset and -out_charset. Normally one will have both identical, if ever.
If conversions are desired then xorriso needs to know the name of the local character set. xorriso can inquire the same info as shell command "locale" with argument "charmap". This may be influenced by environment variables LC_ALL, LC_CTYPE, or LANG and should match the expectations of the terminal.
The default output charset is the local character set of the terminal where xorriso runs. So by default no conversion happens between local filesystem names and emerging names in the image. The situation stays ambigous and the reader has to riddle what character set was used.
By option -auto_charset it is possible to attribute the output charset name to the image. This makes the situation unambigous. But if your terminal character set does not match the character set of the local file names, then this attribute can become plainly wrong and cause problems at read time. To prevent this it is necessary to check whether the terminal properly displays all intended filenames. Check especially the exotic national characters.
To enforce recording of a particular character set name without any conversion at image generation time, set -charset and -local_charset to the desired name, and enable -backslash_codes to avoid evil character display on your terminal.

-charset character_set_name
    Set the character set from which to convert file names when loading an image and to which to convert when writing an image.

-local_charset character_set_name
    Override the system assumption of the local character set name. If this appears necessary, one should consider to set -backslash_codes to "on" in order to avoid dangerous binary codes being sent to the terminal.

Exception processing:

Since the tasks of xorriso are manifold and prone to external influence, there may arise the need for xorriso to report and handle problem events.
Those events get classified when they are detected by one of the software modules and forwarded to reporting and evaluation modules which decide about reactions. Event classes are sorted by severity:
"NEVER" The upper end of the severity spectrum.
"ABORT" The program is being aborted and on its way to end.
"FATAL" The main purpose of the run failed or an important resource failed unexpectedly.
"FAILURE" An important part of the job could not be performed.
"MISHAP" A FAILURE which can be tolerated during ISO image generation.
"SORRY" A less important part of the job could not be performed.
"WARNING" A situation is suspicious of being not intended by the user.
"HINT" A proposal to the user how to achieve better results.
"NOTE" A harmless information about noteworthy circumstances.
"UPDATE" A pacifier message during long running operations.
"DEBUG" A message which would only interest the program developers.
"ALL" The lower end of the severity spectrum.

-abort_on severity
    Set the severity threshold for events to abort the program.
    Useful: "NEVER", "ABORT", "FATAL", "FAILURE" , "MISHAP", "SORRY"
    It may become necessary to abort the program anyway, despite the setting by this option. Expect not many "ABORT" events to be ignorable.
    A special property of this option is that it works preemptive if given as program start argument. I.e. the first -abort_on setting among the start arguments is in effect already when the first operations of xorriso begin. Only "-abort_on" with dash "-" is recognized that way.

-return_with severity exit_value
    Set the threshold and exit_value to be returned at program end if no abort has happened. This is to allow xorriso to go on after problems but to get a failure indicating exit value from the program, nevertheless. Useful is a value lower than the -abort_on threshold, down to "WARNING".
    exit_value may be either 0 (indicating success to the starter of the program) or a number between 32 and 63. Some other exit_values are used by xorriso if it decides to abort the program run:
    1=abort due to external signal
    2=no program arguments given
    3=creation of xorriso main object failed
    4=failure to start libburnia-project.org libraries
    5=program abort during argument processing
    6=program abort during dialog processing

-report_about severity
    Set the threshold for events to be reported.
    Useful: "SORRY", "WARNING", "HINT", "NOTE", "UPDATE", "DEBUG", "ALL"
    Regardless what is set by -report_about, messages get always reported if they reach the severity threshold of -abort_on .
    Event messages are sent to the info channel "I" which is usually stderr but may be influenced by command -pkt_output. Info messages which belong to no event get attributed severity "NOTE".
    A special property of this option is that the first -report_about setting among the start arguments is in effect already when the first operations of xorriso begin. Only "-report_about" with dash "-" is recognized that way.

-signal_handling mode
    Control the installation of a signal handler which shall react on external signals (e.g. from program "kill" or from keys Ctrl+C) or on signals caused by severe program errors.
    Mode "on" is the default. It uses the signal handler of libburn which produces ugly messages but puts much effort in releasing optical drives before xorriso ends.
    Mode "off" as first -signal_handling among the start arguments prevents all own signal precautions of xorriso. Inherited signal handler settings stay as they are.
    It works like "sig_dfl" if given after other signal handling was already established at program start.
    Mode "sig_dfl" uses the system provided default handling of signals, which is normally a sudden abort of the program. To prevent stuck drives, the libburn handler is used during burning, blanking, and formatting on MMC drives.
    Mode "sig_ign" tries to ignore as many signal types as possible. This imposes the risk that xorriso refuses to end until externally kill -9 if performed. kill -9 then imposes the risk that the drive is left in unusable state and needs poweroff to be reset. So during burning, blanking, and formatting wait for at least their normal run time before killing externally.
    A special property of this option is that the first -signal_handling setting among the start arguments is in effect already when the first operations of xorriso begin. Only "-signal_handling" with dash "-" is recognized that way.

-error_behavior occasion behavior
    Control the program behavior at problem event occasions. For now this applies to occasions "image_loading" which is given while an image tree is read from the input device, and to "file_extraction" which is given with osirrox options like -extract.
    With "image_loading" there are three behaviors available:
    "best_effort" goes on with reading after events with severity below FAILURE if the threshold of option -abort_on allows this.
    "failure" aborts image tree reading on first event of at least SORRY. It issues an own FAILURE event. This is the default.
    "fatal" acts like "failure" but issues the own event as FATAL.
    With occasion "file_extraction" there are three behaviors:
    "keep" maintains incompletely extracted files on disk. This is the default.
    "delete" removes files which encountered errors during content extraction.
    "best_effort" starts a revovery attempt by means of -extract_cut if the file content stems from the loaded ISO image and is not filtered.

Dialog mode control:

-dialog "on"|"off"|"single_line"
    Enable or disable to enter dialog mode after all arguments are processed. In dialog mode input lines get prompted via readline or from stdin.
    If no -abort_on severity was set when dialog starts, then "NEVER" is set to avoid abort in most cases of wrong input or other problems. Before dialog begins, the default is "FAILURE" which e.g. aborts on unknown commands.
    Mode "on" supports input of newline characters within quotation marks and line continuation by trailing backslash outside quotation marks. Mode "single_line" does not.

-page length width
    Describe terminal to the text pager. See also above, paragraph Result pager.
    If parameter length is nonzero then the user gets prompted after that number of terminal lines. Zero length disables paging.
    Parameter width is the number of characters per terminal line. It is used to compute the number of terminal lines which get occupied by an output line. A usual terminal width is 80.

-use_readline "on"|"off"
    If "on" then use readline for dialog. Else use plain stdin.
    See also above, paragraph Dialog, Readline, Result pager.

-reassure "on"|"tree"|"off"
    If "on" then ask the user for "y" or "n":
    before deleting or overwriting any file in the ISO image,
    before overwriting any disk file during restore operations,
    before rolling back pending image changes,
    before committing image changes to media,
    before changing the input drive,
    before blanking or formatting media,
    before ending the program.
    With setting "tree" the reassuring prompt will appear for an eventual directory only once and not for each file in its whole subtree.
    Setting "off" silently kills any kind of image file object resp. performs above irrevocable actions.
    To really produce user prompts, option -dialog needs to be set to "on". Note that the prompt does not appear in situations where file removal is forbidden by option -overwrite. -reassure only imposes an additional curb for removing existing file objects.
    Be aware that file objects get deleted from the ISO image immediately after confirmation. They are gone even if the running command gets aborted and its desired effect gets revoked. In case of severe mess-up, consider to use -rollback to revoke the whole session.

Drive and media related inquiry actions:

-devices
    Show list of available MMC drives with the addresses of their libburn standard device files.
    This is only possible when no ISO image changes are pending. After this option was executed, there is no drive current and no image loaded.
    In order to be visible, a device has to offer rw-permissions with its libburn standard device file. Thus it might be only the superuser who is able to see all drives.
    Drives which are occupied by other processes get not shown.

-device_links
    Like -devices, but presenting the drives with addresses of symbolic links which point to the actual device files.
    Modern GNU/Linux systems may shuffle drive addresses from boot to boot. The udev daemon is supposed to create links which always point to the same drive, regardless of its system address. The command -device_links shows the addresses of such links if they begin by "/dev/dvd" or "/dev/cd". Precedence is: "dvdrw", "cdrw", "dvd", "cdrom", "cd".

-toc
    Show media specific table of content. This is the session history of the medium, not the ISO image directory tree.
    In case of overwriteable media holding a valid ISO image, it may happen that only a single session gets shown. But if the first session on the overwriteable media was written by xorriso then a complete session history can be emulated.
    A drive which is incapable of writing may show any media as CD-ROM or DVD-ROM with only one or two sessions on it. The last of these sessions is supposed to be the most recent real session then.
    Some read-only drives and media show no usable session history at all. Option -rom_toc_scan might help.

-mount_cmd drive entity id path
    Emit an appropriate command line for mounting the ISO session indicated by drive, entity and id. The result will be different on GNU/Linux and on FreeBSD.
    drive can be "indev" or "outdev" to indicate already acquired drives, or it can be the path of a not yet acquired drive. Prefix "stdio:" for non-MMC drives is not mandatory.
    entity must be either "sbsector" with the superblock sector address as id, or "track" with a track number as id, or "session" with a session number, or "volid" with a search pattern for the volume id, or "auto" with any text as id.
    path will be used as mount point and must already exist as a directory on disk.
    The command gets printed to the result channel. See option -mount for direct execution of this command.

-mount_opts option[:option...]
    Set options which influence -mount and -mount_cmd. Currently there is only option "exclusive" which is default and its counterpart "shared". The latter causes xorriso not to give up the affected drive with command -mount. On GNU/Linux it adds mount option "loop" which may allow to mount several sessions of the same block device at the same time. One should not write to a mounted optical medium, of course. Take care to umount all sessions before ejecting.

-session_string drive entity id format
    Print to the result channel a text which gets composed according to format and the parameters of the addressed session.
    Formats "linux:"path or "freebsd:"path produce the output of -mount_cmd for the given operating systems.
    In other texts xorriso will substitute the following parameter names. An optional prefix "string:" will be removed.
    "%device%" will be substituted by the mountable device path of the drive address.
    "%sbsector%" will be substituted by the session start sector.
    "%track%", "%session%", "%volid%" will be substituted by track number, session number, resp. volume id of the depicted session.

-print_size
    Print the foreseeable consumption of 2048 byte blocks by next -commit. This can last a while as a -commit gets prepared and only in last moment is revoked by this option. The result depends on several settings and also on the kind of output device. If no -jidgo options are given and not command -as "mkisofs" was used, then -padding (300 kB by default) is not counted as part of the image size.

-tell_media_space
    Print available space on the output medium and the free space after subtracting already foreseeable consumption by next -commit.

-pvd_info
    Print various id strings which can be found in loaded ISO images. Some of them may be changed by options like -volid or -publisher. For these ids -pvd_info reports what would be written with the next -commit.

Navigation in ISO image and disk filesystem:

-cd iso_rr_path
    Change the current working directory in the ISO image. This is prepended to iso_rr_paths which do not begin with '/'.
    It is possible to set the working directory to a path which does not exist yet in the ISO image. The necessary parent directories will be created when the first file object is inserted into that virtual directory. Use -mkdir if you want to enforce the existence of the directory already at first insertion.

-cdx disk_path
    Change the current working directory in the local filesystem. To be prepended to disk_paths which do not begin with '/'.

-pwd
    Tell the current working directory in the ISO image.

-pwdx
    Tell the current working directory in the local filesystem.

-ls iso_rr_pattern [***]
    List files in the ISO image which match shell patterns (i.e. with wildcards '*' '?' '[a-z]'). If a pattern does not begin with '/' then it is compared with addresses relative to -cd.
    Directories are listed by their content rather than as single file item.
    Pattern expansion may be disabled by command -iso_rr_pattern.

-lsd iso_rr_pattern [***]
    Like -ls but listing directories as themselves and not by their content. This resembles shell command ls -d.

-lsl iso_rr_pattern [***]
    Like -ls but also list some of the file attributes. The output format resembles shell command ls -ln.
    File type 'e' indicates the El Torito boot catalog.
    If the file has non-trivial ACL, then a '+' is appended to the permission info. If the file is hidden, then 'I' for "iso_rr", 'J' for "joliet", resp. 'H' for "on" gets appended. Together with ACL it is 'i', 'j', resp. 'h'.

-lsdl iso_rr_pattern [***]
    Like -lsd but also list some of the file attributes. The output format resembles shell command ls -dln.

-lsx disk_pattern [***]
    List files in the local filesystem which match shell patterns. Patterns which do not begin with '/' are used relative to -cdx.
    Directories are listed by their content rather than as single file item.
    Pattern expansion may be disabled by command -disk_pattern.

-lsdx disk_pattern [***]
    Like -lsx but listing directories as themselves and not by their content. This resembles shell command ls -d.

-lslx disk_pattern [***]
    Like -lsx but also listing some of the file attributes. Output format resembles shell command ls -ln.

-lsdlx disk_pattern [***]
    Like -lsdx but also listing some of the file attributes. Output format resembles shell command ls -dln.

-getfacl iso_rr_pattern [***]
    Print the access permissions of the given files in the ISO image using the format of shell command getfacl. If a file has no ACL then it gets fabricated from the -chmod settings. A file may have a real ACL if it was introduced into the ISO image while option -acl was set to "on".

-getfacl_r iso_rr_pattern [***]
    Like -gefacl but listing recursively the whole file trees underneath eventual directories.

-getfattr iso_rr_pattern [***]
    Print the xattr of the given files in the ISO image. If a file has no such xattr then noting is printed for it.

-getfattr_r iso_rr_pattern [***]
    Like -gefattr but listing recursively the whole file trees underneath eventual directories.

-du iso_rr_pattern [***]
    Recursively list size of directories and files in the ISO image which match one of the patterns. similar to shell command du -k.

-dus iso_rr_pattern [***]
    List size of directories and files in the ISO image which match one of the patterns. Similar to shell command du -sk.

-dux disk_pattern [***]
    Recursively list size of directories and files in the local filesystem which match one of the patterns. Similar to shell command du -k.

-dusx disk_pattern [***]
    List size of directories and files in the local filesystem which match one of the patterns. Similar to shell command du -sk.

-findx disk_path [-name pattern] [-type t] [-exec action [params]] --
    Like -find but operating on local filesystem and not on the ISO image. This is subject to the settings of -follow.
    -findx accepts the same -type arguments as -find. Additionally it recognizes type "mountpoint" (or "m") which matches subdirectories which reside on a different device than their parent. It never matches the disk_path given as start address for -findx.
    -findx accepts the -exec actions as does -find. But except the following few actions it will always perform action "echo".
    in_iso reports the path if its counterpart exists in the ISO image. For this the disk_path of the -findx command gets replaced by the iso_rr_path given as parameter.
    E.g.: -findx /home/thomas -exec in_iso /thomas_on_cd --
    not_in_iso reports the path if its counterpart does not exist in the ISO image. The report format is the same as with command -compare.
    add_missing iso_rr_path_start adds the counterpart if it does not yet exist in the ISO image and marks it for "rm_merge" as non-removable.
    E.g.: -findx /home/thomas -exec add_missing /thomas_on_cd --
    is_full_in_iso reports if the counterpart in the ISO image contains files. To be used with -type "m" to report mount points.
    empty_iso_dir deletes all files from the counterpart in the ISO image. To be used with -type "m" to truncate mount points.
    estimate_size prints a lower and an upper estimation of the number of blocks which the found files together will occupy in the emerging ISO image. This does not account for the superblock, for the directories in the -findx path, or for image padding.
    list_extattr mode prints a script to the result channel, which would use FreeBSD command setextattr to set the file's xattr name-value pairs of user namespace. See -find for a description of parameter mode.
    E.g. -exec list_extattr e --

-compare disk_path iso_rr_path
    Compare attributes and eventual data file content of a fileobject in the local filesystem with a file object in the ISO image. The iso_rr_path may well point to an image file object which is not yet committed, i.e. of which the data content still resides in the local filesystem. Such data content is prone to externally caused changes.
    If iso_rr_path is empty then disk_path is used as path in the ISO image too.
    Differing attributes are reported in detail, differing content is summarized. Both to the result channel. In case of no differences no result lines are emitted.

-compare_r disk_path iso_rr_path
    Like -compare but working recursively. I.e. all file objects below both addresses get compared whether they have counterparts below the other address and whether both counterparts match.

-compare_l disk_prefix iso_rr_prefix disk_path [***]
    Perform -compare_r with each of the disk_path arguments. iso_rr_path will be composed from disk_path by replacing disk_prefix by iso_rr_prefix.

-show_stream iso_rr_path [***]
    Display the content stream chain of data files in the ISO image. The chain consists of the iso_rr_name and one or more streams, separated by " < " marks. A stream description consists of one or more texts, separated by ":" characters. The first text tells the stream type, the following ones, if ever, describe its individual properties. Frequently used types are:
     disk:'disk_path' for local filesystem objects.
     image:'iso_rr_path' for ISO image file objects.
     cout:'disk_path offset count' for -cut_out files.
     extf:'filter_name' for external filters.
    Example:
     '/abc/xyz.gz' < extf:'gzip' < disk:'/home/me/x'

-show_stream_r iso_rr_path [***]
    Like -show_stream but working recursively.

Evaluation of readability and recovery:

It is not uncommon that optical media produce read errors. The reasons may be various and get obscured by error correction which is performed by the drives and based on extra data on the media. If a drive returns data then one can quite trust that they are valid. But at some degree of read problems the correction will fail and the drive is supposed to indicate error.
xorriso can scan a medium for readable data blocks, classify them according to their read speed, save them to a file, and keep track of successfuly saved blocks for further tries on the same medium.
By option -md5 checksums may get recorded with data files and whole sessions. These checksums are reachable only via indev and a loaded image. They work independently of the media type and can detect transmission errors.

-check_media [option [option ...]] --
    Try to read data blocks from the indev drive, optionally copy them to a disk file, and finally report about the encountered quality. Several options may be used to modify the default behavior.
    The options given with this command override the default settings which may have been changed by option -check_media_defaults. See there for a description of options.
    The result list tells intervals of 2 KiB blocks with start address, number of blocks and quality. Qualities which begin with "+" are supposed to be valid readable data. Qualities with "-" are unreadable or corrupted data. "0" indicates qualities which are not covered by the check run or are regularly allowed to be unreadable (e.g. gaps between tracks).
    Alternatively it is possible to report damaged files rather than blocks.
    If -md5 is "on" then the default mode what=tracks looks out for libisofs checksum tags for the ISO session data and checks them against the checksums computed from the data stream.

-check_media_defaults [option [option ...]] --
    Preset options for runs of -check_media, -extract_cut and best_effort file extraction. Options given with -check_media will override the preset options. -extract_cut will override some options automatically.
    An option consists of a keyword, a "=" character, and a value. Options may override each other. So their sequence matters.
    The default setting at program start is:
    use=indev what=tracks min_lba=-1 max_lba=-1 retry=default
    time_limit=28800 item_limit=100000 data_to='' event=ALL
    abort_file=/var/opt/xorriso/do_abort_check_media
    sector_map='' map_with_volid=off patch_lba0=off report=blocks
    bad_limit=valid slow_limit=1.0 chunk_size=0s
    Option "reset=now" restores these startup defaults.
    Non-default options are:
    report="files" lists the files which use damaged blocks (not with use=outdev). The format is like with find -exec report_damage. Note that a MD5 session mismatch marks all files of the session as damaged. If finer distinction is desired, perform -md5 off before -check_media.
    report="blocks_files" first lists damaged blocks and then affected files.
    use="outdev" reads from the output drive instead of the input drive. This avoids loading the ISO image tree from media.
    use="sector_map" does not read any media but loads the file given by option sector_map= and processes this virtual outcome.
    what="disc" scans the payload range of a medium without respecting track gaps.
    what="image" similar to "disc", but restricts scanning to the range of the ISO 9660 image, if present.
    min_lba=limit omits all blocks with addresses lower than limit.
    max_lba=limit switches to what=disc and omits all blocks above limit.
    retry="on" forces read retries with single blocks when the normal read chunk produces a read error. By default, retries are only enabled with CD media. "retry=off" forbits retries for all media types.
    abort_file=disk_path gives the path of the file which may abort a scan run. Abort happens if the file exists and its mtime is not older than the start time of the run. Use shell command "touch" to trigger this. Other than an aborted program run, this will report the tested and untested blocks and go on with running xorriso.
    time_limit=seconds gives the number of seconds after which the scan shall be aborted. This is useful for unattended scanning of media which may else overwork the drive in its effort to squeeze out some readable blocks. Abort may be delayed by the drive gnawing on the last single read operation. Value -1 means unlimited time.
    item_limit=number gives the number of report list items after which to abort. Value -1 means unlimited item number.
    data_to=disk_path copies the valid blocks to the given file.
    event=severity sets the given severity for a problem event which shall be issued at the end of a check run if data blocks were unreadable or failed to match recorded MD5 checksums. Severity "ALL" disables this event.
    sector_map=disk_path tries to read the file given by disk_path as sector bitmap and to store such a map file after the scan run. The bitmap tells which blocks have been read successfully in previous runs. It allows to do several scans on the same medium, even with intermediate eject, in order to collect readable blocks whenever the drive is lucky enough to produce them. The stored file contains a human readable TOC of tracks and their start block addresses, followed by binary bitmap data.
    map_with_volid="on" examines tracks whether they are ISO images and prints their volume ids into the human readable TOC of sector_map=.
    patch_lba0="on" transfers within the data_to= file a copy of the currently loaded session head to the start of that file and patches it to be valid at that position. This makes the loaded session the default session of the image file when it gets mounted or loaded as stdio: drive. But it usually makes the original session 1 inaccessible.
    patch_lba0="force" performs patch_lba0="on" even if xorriso believes that the copied data are not valid.
    patch_lba0= may also bear a number. If it is 32 or higher it is taken as start address of the session to be copied. In this case it is not necessary to have an -indev and a loaded image. ":force" may be appended after the number.
    bad_limit=threshold sets the highest quality which shall be considered as damage. Choose one of "good", "md5_match", "slow", "partial", "valid", "untested", "invalid", "tao_end", "off_track", "md5_mismatch", "unreadable".
    slow_limit=threshold sets the time threshold for a single read chunk to be considered slow. This may be a fractional number like 0.1 or 1.5.
    chunk_size=size sets the number of bytes to be read in one read operation. This gets rounded down to full blocks of 2048 bytes. 0 means automatic size.

-check_md5 severity iso_rr_path [***]
    Compare the data content of the given files in the loaded image with their recorded MD5 checksums, if there are any. In case of any mismatch an event of the given severity is issued. It may then be handled by appropriate settings of options -abort_on or -return_with which both can cause non-zero exit values of the program run. Severity ALL suppresses that event.
    This option reports match and mismatch of data files to the result channel. Non-data files cause NOTE events. There will also be UPDATE events from data reading.
    If no iso_rr_path is given then the whole loaded session is compared with its MD5 sum. Be aware that this covers only one session and not the whole image if there are older sessions.

-check_md5_r severity iso_rr_path [***]
    Like -check_md5 but checking all data files underneath the given paths. Only mismatching data files will be reported.

osirrox ISO-to-disk restore options:

Normally xorriso only writes to disk files which were given as stdio: pseudo-drives or as log files. But its alter ego osirrox is able to extract file objects from ISO images and to create, overwrite, or delete file objects on disk.
Disk file exclusions by -not_mgt, -not_leaf, -not_paths apply. If disk file objects already exist then the settings of -overwrite and -reassure apply. But -overwrite "on" only triggers the behavior of -overwrite "nondir". I.e. directories cannot be deleted.
Access permissions of files in the ISO image do not restrict restoring. The directory permissions on disk have to allow rwx.

-osirrox "on"|"device_files"|"off"|"banned"|[:option:...]
    Setting "off" disables disk filesystem manipulations. This is the default unless the program was started with leafname "osirrox". Elsewise the capability to restore files can be enabled explicitly by -osirrox "on". It can be irrevocably disabled by -osirrox "banned".
    To enable restoring of special files by "device_files" is potentially dangerous. The meaning of the number st_rdev (see man 2 stat) depends much on the operating system. Best is to restore device files only to the same system from where they were copied. If not enabled, device files in the ISO image are ignored during restore operations.
    Due to a bug of previous versions, device files from previous sessions might have been altered to major=0, minor=1. So this combination does not get restored.
    Option "concat_split_on" is default. It enables restoring of split file directories as data files if the directory contains a complete collection of -cut_out part files. With option "concat_split_off" such directories are handled like any other ISO image directory.
    Option "auto_chmod_off" is default. If "auto_chmod_on" is set then access restrictions for disk directories get circumvented if those directories are owned by the effective user who runs xorriso. This happens by temporarily granting rwx permission to the owner.
    Option "sort_lba_on" may improve read performance with optical drives. It allows to restore large numbers of hard links without exhausting -temp_mem_limit. It does not preserve directory mtime and it needs -osirrox option auto_chmod_on in order to extract directories which offer no write permission. Default is "sort_lba_off".
    Option "o_excl_on" is the default unless the program was started with leafname "osirrox". On GNU/Linux it tries to avoid using drives which are mounted or in use by other libburn programs. Option "o_excl_off" allows on GNU/Linux to access such drives. Drives which get acquired while "o_excl_off" will refuse to get blanked, formatted, written, or ejected. But be aware that even harmless inquiries can spoil ongoing burns of CD-R[W] and DVD-R[W].
    Option "strict_acl_off" is default. It tolerates on FreeBSD the presence of directory "default" ACLs in the ISO image. With "strict_acl_on" these GNU/Linux ACLs cause on FreeBSD a FAILURE event during restore with -acl "on".

-extract iso_rr_path disk_path
    Copy the file objects at and underneath iso_rr_path to their corresponding addresses at and underneath disk_path. This is the inverse of -map or -update_r.
    If iso_rr_path is a directory and disk_path is an existing directory then both trees will be merged. Directory attributes get extracted only if the disk directory is newly created by the copy operation. Disk files get removed only if they are to be replaced by file objects from the ISO image.
    As many attributes as possible are copied together with restored file objects.

-extract_single iso_rr_path disk_path
    Like -extract, but if iso_rr_path is a directory then its sub tree gets not restored.

-extract_l iso_rr_prefix disk_prefix iso_rr_path [***]
    Perform -extract with each of the iso_rr_path arguments. disk_path will be composed from iso_rr_path by replacing iso_rr_prefix by disk_prefix.

-extract_cut iso_rr_path byte_offset byte_count disk_path
    Copy a byte interval from a data file out of an ISO image into a newly created disk file. The main purpose for this is to allow handling of large files if they are not supported by mount -t iso9660 and if the reading system is unable to buffer them as a whole.
    If the data bytes of iso_rr_path are stored in the loaded ISO image, and no filter is applied, and byte_offset is a multiple of 2048, then a special run of -check_media is performed. It may be quicker and more rugged than the general reading method.

-cpx iso_rr_path [***] disk_path
    Copy single leaf file objects from the ISO image to the address given by disk_path. If more then one iso_rr_path is given then disk_path must be a directory or non-existent. In the latter case it gets created and the extracted files get installed in it with the same leafnames.
    Missing directory components in disk_path will get created, if possible.
    Directories are allowed as iso_rr_path only with -osirrox "concat_split_on" and only if they actually represent a complete collection of -cut_out split file parts.

-cpax iso_rr_path [***] disk_path
    Like -cpx but restoring mtime, atime as in ISO image and trying to set ownership and group as in ISO image.

-cp_rx iso_rr_path [***] disk_path
    Like -cpx but also extracting whole directory trees from the ISO image.
    The resulting disk paths are determined as with shell command cp -r : If disk_path is an existing directory then the trees will be inserted or merged underneath this directory and will keep their leaf names. The ISO directory "/" has no leaf name and thus gets mapped directly to disk_path.

-cp_rax iso_rr_path [***] disk_path
    Like -cp_rx but restoring mtime, atime as in ISO image and trying to set ownership and group as in ISO image.

-paste_in iso_rr_path disk_path byte_offset byte_count
    Read the content of a ISO data file and write it into a data file on disk beginning at the byte_offset. Write at most byte_count bytes. This is the inverse of option -cut_out.

-mount drive entity id path
    Produce the same line as -mount_cmd and then execute it as external program run after giving up the depicted drive. See also -mount_opts. This demands -osirrox to be enabled and normally will succeed only for the superuser. For safety reasons the mount program is only executed if it is reachable as /bin/mount or /sbin/mount.

Command compatibility emulations:

Writing of ISO 9660 on CD is traditionally done by program mkisofs as ISO 9660 image producer and cdrecord as burn program. xorriso does not strive for their comprehensive emulation. Nevertheless it is ready to perform some of its core tasks under control of commands which in said programs trigger comparable actions.

-as personality option [options] --
    Perform the variable length option list as sparse emulation of the program depicted by the personality word.
    Personality "mkisofs" accepts the options listed with:
      -as mkisofs -help --
    Among them: -R (always on), -r, -J, -o, -M, -C, -dir-mode, -file-mode, -path-list, -m, -exclude-list, -f, -print-size, -pad, -no-pad, -V, -v, -version, -graft-points, -z, -no-emul-boot, -b, -c, -boot-info-table, -boot-load-size, -input-charset, -G, -output-charset, -U, -hide, -hide-joliet, -hide-list, -hide-joliet-list, file paths and pathspecs. A lot of options are not supported and lead to failure of the mkisofs emulation. Some are ignored, but better do not rely on this tolerance.
    The supported options are documented in detail in xorrisofs.info and in man xorrisofs. The description here is focused on the effect of mkisofs emulation in the context of a xorriso run.
    Other than with the "cdrecord" personality there is no automatic -commit at the end of a "mkisofs" option list. Verbosity settings -v (= "UPDATE") and -quiet (= "SORRY") persist. The output file persists until things happen like -commit, -rollback, -dev, or end of xorriso. -pacifier gets set to "mkisofs" if files are added to the image.
    -graft-points is equivalent to -pathspecs on. Note that pathspecs without "=" are interpreted differently than with xorriso option -add. Directories get merged with the root directory of the ISO image, other filetypes get mapped into that root directory.
    If pathspecs are given and if no output file was chosen before or during the "mkisofs" option list, then standard output (-outdev "-") will get into effect. If -o points to a regular file, then it will be truncated to 0 bytes when finally writing begins. This truncation does not happen if the drive is chosen by xorriso options before -as mkisofs or after its list delimiter. Directories and symbolic links are no valid -o targets.
    Writing to stdout is possible only if -as "mkisofs" was among the start arguments or if other start arguments pointed the output drive to standard output.
    -print-size inhibits automatic image production at program end. This ban is lifted only if the pending image changes get discarded.
    Padding is counted as part of the ISO image if not option --emul-toc is given.
    If no -iso-level is given, then level 1 is chosen when the first file or directory is added to the image. At the same occasion directory names get allowed to violate the standard by -compliance option allow_dir_id_ext. This may be avoided by option -disallow_dir_id_ext.
    Option -root is supported. Option -old-root is implemented by xorriso commands -mkdir, -cp_clone, -find update_merge, and -find rm_merge. -root and -old-root set command -disk_dev_ino to "ino_only" and -md5 to "on", by default. -disk_dev_ino can be set to "off" by --old-root-no-ino resp. to "on" by --old-root-devno . -md5 can be set to "off" by --old-root-no-md5 .
    Not original mkisofs options are --quoted_path_list , --hardlinks , --acl , --xattr , --md5 , --stdio_sync . They work like the xorriso options with the same name and hardcoded argument "on", e.g. -acl "on". Explicit arguments are expected by --stdio_sync and --scdbackup_tag.
    The capability to preserve multi-session history on overwriteable media gets disabled by default. It can be enabled by using --emul-toc with the first session. See -compliance no_emul_toc.
    --sort-weight gets as arguments a number and an iso_rr_path. The number becomes the LBA sorting weight of regular file iso_rr_path or of all regular files underneath directory iso_rr_path. (See -find -exec sort_weight).
    Adopted from grub-mkisofs are --protective-msdos-label (see -boot_image grub partition_table=on) and --modification-date=YYYYMMDDhhmmsscc (see -volume_date uuid). For EFI bootable GRUB boot images use --efi-boot. It performs -boot_image grub efi_path= surrounded by two -boot_image "any" "next". Alternative option -e from Fedora genisoimage sets bin_path and platform_id for EFI, but performs no "next".
    For MBR bootable ISOLINUX images there is -isohybrid-mbr FILE, where FILE is one of the Syslinux files mbr/isohdp[fp]x*.bin . Use this instead of -G to apply the effect of -boot_image isolinux partition_table=on.
    --boot-catalog-hide is -boot_image any cat_hidden=on.
    -mips-boot is the same as -boot_image any mips_path= .
    -mipsel-boot leads to mipsel_path= .
    -partition_offset number is -boot_image any partition_offset=number.
    Option -append_partition is supported.
    -untranslated_name_len number is -compliance untranslated_name_len=number.
    --old-empty is -compliance old_empty.
    The options of genisoimage Jigdo Template Extraction are recognized and performed via xorriso option -jigdo. See the "Alias:" names there for the meaning of the genisoimage options.
    Personalities "xorrisofs", "genisoimage", and "genisofs" are aliases for "mkisofs".
    If xorriso is started with one of the leafnames "xorrisofs", "genisofs", "mkisofs", or "genisoimage", then it performs -read_mkisofsrc and prepends -as "genisofs" to the command line arguments. I.e. all arguments will be interpreted mkisofs style until "--" is encountered. From then on, options are interpreted as xorriso options.
    --no_rc as first argument of such a program start prevents interpretation of startup files. See section FILES below.
    Personality "cdrecord" accepts the options listed with:
      -as cdrecord -help --
    Among them: -v, dev=, speed=, blank=, fs=, -eject, -atip, padsize=, tsize=, -isosize, -multi, -msinfo, --grow_overwriteable_iso, write_start_address=, track source file path or "-" for standard input as track source.
    It ignores most other options of cdrecord and cdrskin but refuses on -audio, -scanbus, and on blanking modes unknown to xorriso.
    The scope is only a single data track per session to be written to blank, overwriteable, or appendable media. The medium gets closed if closing is applicable and not option -multi is present.
    If an input drive was aquired, then it is given up. This is only allowed if no image changes are pending.
    dev= must be given as xorriso device address. Addresses like 0,0,0 or ATA:1,1,0 are not supported.
    If a track source is given, then an automatic -commit happens at the end of the "cdrecord" option list.
    --grow_overwriteable_iso enables emulation of multi-session on overwriteable media. To enable emulation of a TOC, the first session needs -C 0,32 with -as mkisofs (but no -M) and --grow_overwriteable_iso write_start_address=32s with -as cdrecord.
    A much more elaborate libburn based cdrecord emulator is the program cdrskin.
    Personalites "xorrecord", "wodim", and "cdrskin" are aliases for "cdrecord".
    If xorriso is started with one of the leafnames "xorrecord", "cdrskin", "cdrecord", or "wodim", then it automatically prepends -as "cdrskin" to the command line arguments. I.e. all arguments will be interpreted cdrecord style until "--" is encountered. From then on, options are interpreted as xorriso options.
    --no_rc as first argument of such a program start prevents interpretation of xorriso startup files. See section FILES below.

-read_mkisofsrc
    Try one by one to open for reading:
     ./.mkisofsrc , $MKISOFSRC , $HOME/.mkisofsrc , $(dirname $0)/.mkisofsrc
    On success interpret the file content as of man mkisofs CONFIGURATION, and end this command. Do 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 (-application_id) , PUBL (-publisher) , SYSI (-system_id) , VOLI (-volid) , VOLS (-volset_id)
    Any other lines will be silently ignored.

-pacifier behavior_code
    Control behavior of UPDATE pacifiers during write operations. The following behavior codes are defined:
    "xorriso" is the default format:
    Writing: sector XXXXX of YYYYYY [fifo active, nn% fill]
    "cdrecord" looks like:
    X of Y MB written (fifo nn%) [buf mmm%]
    "mkisofs"
    nn% done, estimate finish Tue Jul 15 20:13:28 2008

-scdbackup_tag list_path record_name
    Set the parameter "name" for a scdbackup checksum record. It will be appended in an scdbackup checksum tag to the -md5 session tag if the image starts at LBA 0. This is the case if it gets written as first session onto a sequential medium, or piped into a program, named pipe or character device.
    If list_path is not empty then the record will also be appended to the data file given by this path.
    Program scdbackup_verify will recognize and verify tag resp. record.

Scripting, dialog and program control features:

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

-options_from_file fileaddress
    Read quoted input from fileaddress and execute it like dialog lines. Empty lines and lines which begin by # are ignored. Normally one line should hold one xorriso command and all its arguments. Nevertheless lines may be concatenated by a trailing backslash.
    See also section "Command processing", paragraph "Quoted input".

-help
    Print helptext.

-version
    Print program name and version, component versions, license.

-list_extras code
    Tell whether certain extra features were enabled at compile time. Code "all" lists all features and a headline. Other codes pick a single feature. Code "codes" lists them. They share names with related commands (see also there):
    "acl" tells whether xorriso has an adapter for local filesystems ACLs.
    "xattr" tells whether xorriso has an adapter for local filesystems EA.
    "jigdo" tells whether production of Jigdo files is possible.
    "zisofs" tells whether zisofs and built-in gzip filters are enabled.
    "external_filter" tells whether external filter processes are allowed and whether they are allowed if real user id and effective user id differ.
    "dvd_obs" tells whether 64 kB output to DVD media is default.
    "use_readline" tells whether readline may be enabled in dialog mode.

-history textline
    Copy textline into libreadline history.

-status mode|filter
    Print the current settings of xorriso. Modes:
      short... print only important or altered settings
      long ... print all settings including defaults
      long_history like long plus history lines
    Filters begin with '-' and are compared literally against the output lines of -status:long_history. A line is put out only if its start matches the filter text. No wildcards.

-status_history_max number
    Set maximum number of history lines to be reported with -status "long_history".

-list_delimiter word
    Set the list delimiter to be used instead of "--". It has to be a single word, must not be empty, not longer than 80 characters, and must not contain quotation marks.
    For brevity the list delimiter is referred as "--" throughout this text.

-backslash_codes "on"|"off"|mode[:mode]
    Enable or disable the interpretation of symbolic representations of special characters with quoted input, or with program arguments, or with program text output. If enabled the following translations apply:
     \a=bell(007) \b=backspace(010) \e=Escape(033) \f=formfeed(014)
     \n=linefeed(012) \r=carriage_return(015) \t=tab(011)
     \v=vtab(013) \\=backslash(134) \[0-7][0-7][0-7]=octal_code
     \x[0-9a-f][0-9a-f]=hex_code \cC=control-C
    Translations can occur with quoted input in 3 modes:
     "in_double_quotes" translates only inside " quotation.
     "in_quotes" translates inside " and ' quotation.
     "with_quoted_input" translates inside and outside quotes.
    With the start program arguments there is mode:
     "with_program_arguments" translates all program arguments.
    Mode "encode_output" encodes output characters. It combines "encode_results" with "encode_infos". Inside single or double quotation marks encoding applies to ASCII characters octal 001 to 037 , 177 to 377 and to backslash(134). Outside quotation marks some harmless control characters stay unencoded: bell(007), backspace(010), tab(011), linefeed(012), formfeed(014), carriage_return(015).
    Mode "off" is default and disables any translation. Mode "on" is "with_quoted_input:with_program_arguments:encode_output".

-temp_mem_limit number["k"|"m"]
    Set the maximum size of temporary memory to be used for image dependent buffering. Currently this applies to pattern expansion, LBA sorting, restoring of hard links.
    Default is 16m = 16 MiB, minimum 64k = 64 kiB, maximum 1024m = 1 GiB.

-print  text
    Print a text line to the result channel which is by default stdout.

-print_info  text
    Print a text line to the info channel which is by default stderr.

-print_mark  text
    Print a text line to the mark channel which is by default directed to both, result and info channel. An empty text will cause no output at all.

-prompt text
    Show text at beginning of output line and wait for the user to hit the Enter key resp. to send a line via stdin.

-sleep seconds
    Wait for the given number of seconds before perfoming the next command. Expect coarse granularity no better than 1/100 seconds.

-errfile_log mode path|channel
    If problem events are related to input files from the filesystem, then their disk_paths can be logged to a file or to output channels R or I.
    Mode can either be "plain" or "marked". The latter causes marker lines which give the time of log start, burn session start, burn session end, log end or program end. In mode "plain", only the file paths are logged.
    If path is "-" or "-R" then the log is directed to the result channel. Path "-I" directs it to the info message channel. Any text that does not begin with "-" is used as path for a file to append the log lines.
    Problematic files can be recorded multiple times during one program run. If the program run aborts then the list might not be complete because some input file arguments might not have been processed at all.
    The errfile paths are transported as messages of very low severity "ERRFILE". This transport becomes visible with -report_about "ALL".

-session_log path
    If path is not empty it gives the address of a plain text file where a log record gets appended after each session. This log can be used to determine the start_lba of a session for mount options -o sbsector= resp. -s from date or volume id.
    Record format is: timestamp start_lba size volume-id
    The first three items are single words, the rest of the line is the volume id.

-scsi_log "on"|"off"
    Mode "on" enables very verbous logging of SCSI commands and drive replies. Logging messages get printed to stderr, not to any of the xorriso output channels.
    A special property of this option is that the first -scsi_log setting among the start arguments is in effect already when the first operations of xorriso begin. Only "-scsi_log" with dash "-" is recognized that way.

-end
    End program after writing pending changes.

-rollback_end
    Discard pending changes. End program immediately.

# any text
    Only in dialog or file execution mode, and only as first non-whitespace in line: Do not execute the line but store it in readline history.

Support for frontend programs via stdin and stdout:

-pkt_output "on"|"off"
    Consolidate text output on stdout and classify each line by a channel indicator:
     'R:' for result lines,
     'I:' for notes and error messages,
     'M:' for -mark texts.
    Next is a decimal number of which only bit 0 has a meaning for now. 0 means no newline at end of payload, 1 means that the newline character at the end of the output line belongs to the payload. After another colon and a blank follows the payload text.
    Example:
     I:1: enter option and arguments :

-logfile channel fileaddress
    Copy output of a channel to the given file. Channel may be one of: "." for all channels, "I" for info messages, "R" for result lines, "M" for -mark texts.

-mark text
    If text is not empty it will get put out on "M" channel each time xorriso is ready for the next dialog line or before xorriso performs a command that was entered to the pager prompt.

-prog text
    Use text as name of this program in subsequent messages

-prog_help text
    Use text as name of this program and perform -help.

EXAMPLES

  Overview of examples:
As superuser learn about available drives
Blank medium and compose a new ISO image as batch run
A dialog session doing about the same
Manipulate an existing ISO image on the same medium
Copy modified ISO image from one medium to another
Bring a prepared ISOLINUX tree onto medium and make it bootable
Change existing file name tree from ISO-8859-1 to UTF-8
Operate on storage facilities other than optical drives
Burn an existing ISO image file to medium
Perform multi-session runs as of cdrtools traditions
Let xorriso work underneath growisofs
Adjust thresholds for verbosity, exit value and program abort
Examples of input timestrings
Incremental backup of a few directory trees
Restore directory trees from a particular ISO session to disk
Try to retrieve blocks from a damaged medium

  As superuser learn about available drives
On Linux or FreeBSD consider to give rw-permissions to those users or groups which shall be able to use the drives with xorriso. On Solaris use pfexec. Consider to restrict privileges of xorriso to "base,sys_devices" and to give r-permission to user or group.
$ xorriso -device_links
1 -dev '/dev/cdrom1' rwrw-- : 'TSSTcorp' 'DVD-ROM SH-D162C
1 -dev '/dev/cdrw' rwrw-- : 'TSSTcorp' 'CDDVDW SH-S223B'
2 -dev '/dev/cdrw3' rwrw-- : 'HL-DT-ST' 'BDDVDRW_GGC-H20L'

  Blank medium and compose a new ISO image as batch run
Aquire drive /dev/sr2, make medium ready for writing a new image, fill the image with the files from hard disk directories /home/me/sounds and /home/me/pictures.
Because no -dialog "on" is given, the program will then end by writing the session to the medium.
$ xorriso -outdev /dev/sr2 \
 -blank as_needed \
 -map /home/me/sounds /sounds \
 -map /home/me/pictures /pictures
The ISO image may be shaped in a more elaborate way like the following: Omit some unwanted stuff by removing it from the image directory tree. Reintroduce some wanted stuff.
$ cd /home/me
$ xorriso -outdev /dev/sr2 \
 -blank as_needed \
 -map /home/me/sounds /sounds \
 -map /home/me/pictures /pictures \
 -rm_r \
   /sounds/indecent \
   '/pictures/*private*' \
   /pictures/confidential \
   -- \
 -cd / \
 -add pictures/confidential/work* --
Note that '/pictures/*private*' is a pattern for iso_rr_paths while pictures/confidential/work* gets expanded by the shell with addresses from the hard disk. Options -add and -map have different argument rules but finally the same effect: they put files into the image.

  A dialog session doing about the same
Some settings are already given as start argument. The other activities are done as dialog input. The pager gets set to 20 lines of 80 characters.
The drive is acquired by option -dev rather than -outdev in order to see the message about its current content. By option -blank this content is made ready for being overwritten and the loaded ISO image is made empty.
In order to be able to eject the medium, the session needs to be committed explicitly.
$ xorriso -dialog on -page 20 80 -disk_pattern on
enter option and arguments :
-dev /dev/sr2
enter option and arguments :
-blank as_needed
enter option and arguments :
-map /home/me/sounds /sounds -map /home/me/pictures /pictures
enter option and arguments :
-rm_r /sounds/indecent /pictures/*private* /pictures/confidential
enter option and arguments :
-cdx /home/me/pictures -cd /pictures
enter option and arguments :
-add confidential/office confidential/factory
enter option and arguments :
-du /
enter option and arguments :
-commit_eject all -end

  Manipulate an existing ISO image on the same medium
Load image from drive. Remove (i.e. hide) directory /sounds and its subordinates. Rename directory /pictures/confidential to /pictures/restricted. Change access permissions of directory /pictures/restricted. Add new directory trees /sounds and /movies. Burn to the same medium, check whether the tree can be loaded, and eject.
$ xorriso -dev /dev/sr2 \
 -rm_r /sounds -- \
 -mv \
   /pictures/confidential \
   /pictures/restricted \
   -- \
 -chmod go-rwx /pictures/restricted -- \
 -map /home/me/prepared_for_dvd/sounds_dummy /sounds \
 -map /home/me/prepared_for_dvd/movies /movies \
 -commit -eject all

  Copy modified ISO image from one medium to another
Load image from input drive. Do the same manipulations as in the previous example. Aquire output drive and blank it. Burn the modified image as first and only session to the output drive.
$ xorriso -indev /dev/sr2 \
 -rm_r /sounds -- \
 ...
 -outdev /dev/sr0 -blank as_needed \
 -commit -eject all

  Bring a prepared ISOLINUX tree onto medium and make it bootable
The user has already created a suitable file tree on disk and copied the ISOLINUX files into subdirectory ./boot/isolinux of that tree. Now xorriso can burn an El Torito bootable medium:
$ xorriso -outdev /dev/sr0 -blank as_needed \
   -map /home/me/ISOLINUX_prepared_tree / \
   -boot_image isolinux dir=/boot/isolinux

  Change existing file name tree from ISO-8859-1 to UTF-8
This example assumes that the existing ISO image was written with character set ISO-8859-1 but that the readers expected UTF-8. Now a new session with the same files gets added with converted file names. In order to avoid any weaknesses of the local character set, this command pretends that it uses already the final target set UTF-8. Therefore strange file names may appear in messages, which will be made terminal-safe by option -backslash_codes.
$ xorriso -in_charset ISO-8859-1 -local_charset UTF-8 \
   -out_charset UTF-8 -backslash_codes on -dev /dev/sr0 \
   -alter_date m +0 / -- -commit -eject all

  Operate on storage facilities other than optical drives
Full read-write operation is possible with regular files and block devices:
$ xorriso -dev /tmp/regular_file ...
Paths underneath /dev normally need prefix "stdio:"
$ xorriso -dev stdio:/dev/sdb ...
If /dev/sdb is to be used frequently and /dev/sda is the system disk, then consider to place the following lines in a xorriso Startup File. They allow to use /dev/sdb without prefix and protect disk /dev/sda from xorriso:
  -drive_class banned /dev/sda*
  -drive_class harmless /dev/sdb
Other writeable file types are supported write-only:
$ xorriso -outdev /tmp/named_pipe ...
Among the write-only drives is standard output:
$ xorriso -outdev - \
 ...
 | gzip >image.iso.gz

  Burn an existing ISO image file to medium
Actually this works with any kind of data, not only ISO images:
$ xorriso -as cdrecord -v dev=/dev/sr0 blank=as_needed image.iso

  Perform multi-session runs as of cdrtools traditions
Between both processes there can be performed arbitrary transportation or filtering.
The first session is written like this:
$ xorriso -as mkisofs prepared_for_iso/tree1 | \
 xorriso -as cdrecord -v dev=/dev/sr0 blank=fast -multi -eject -
Follow-up sessions are written like this:
$ dd if=/dev/sr0 count=1 >/dev/null 2>&1
$ m=$(xorriso -as cdrecord dev=/dev/sr0 -msinfo)
$ xorriso -as mkisofs -M /dev/sr0 -C $m prepared_for_iso/tree2 | \
 xorriso -as cdrecord -v dev=/dev/sr0 -waiti -multi -eject -
Always eject the drive tray between sessions. The old sessions get read via /dev/sr0. Its device driver might not be aware of the changed content before it loads the medium again. In this case the previous session would not be loaded and the new session would contain only the newly added files.
For the same reason do not let xorriso -as cdrecord load the medium, but rather do this manually or by a program that reads from /dev/sr0.
This example works for multi-session media only. Add cdrskin option --grow_overwriteable_iso to all -as cdrecord runs in order to enable multi-session emulation on overwriteable media.

  Let xorriso work underneath growisofs
growisofs expects an ISO formatter program which understands options -C and -M. If xorriso gets started by name "xorrisofs" then it is suitable for that.
$ 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 -- outdev - -update_r /my/files /files
$ growisofs -M /dev/dvd -- outdev - -update_r /my/files /files
growisofs has excellent burn capabilities with DVD and BD. It does not emulate session history on overwriteable media, though.

  Adjust thresholds for verbosity, exit value and program abort
Be quite verbous, exit 32 if severity "FAILURE" was encountered, do not abort prematurely but forcibly go on until the end of commands.
$ xorriso ... \
 -report_about UPDATE \
 -return_with FAILURE 32 \
 -abort_on NEVER \
 ...

  Examples of input timestrings
As printed by program date: 'Thu Nov 8 14:51:13 CET 2007'
The same without ignored parts: 'Nov 8 14:51:13 2007'
The same as expected by date: 110814512007.13
Four weeks in the future: +4w
The current time: +0
Three hours ago: -3h
Seconds since Jan 1 1970: =1194531416

  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. Accelerated comparison is enabled at the expense of potentially larger backup size. Only media with the expected volume id or blank media are accepted. Files with names matching *.o or *.swp get excluded explicitly.
When done with writing the new session gets checked by its recorded MD5.
$ xorriso \
 -abort_on FATAL \
 -for_backup -disk_dev_ino on \
 -assert_volid 'PROJECTS_MAIL_*' FATAL \
 -dev /dev/sr0 \
 -volid PROJECTS_MAIL_"$(date '+%Y_%m_%d_%H%M%S')" \
 -not_leaf '*.o' -not_leaf '*.swp' \
 -update_r /home/thomas/projects /projects \
 -update_r /home/thomas/personal_mail /personal_mail \
 -commit -toc -check_md5 FAILURE -- -eject all
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.
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. To apply zisofs compression to those data files which get newly copied from the local filesystem, insert these options immediately before -commit :
 -hardlinks perform_update \
 -find / -type f -pending_data -exec set_filter --zisofs -- \
Options -disk_dev_ino and -for_backup depend on stable device and inode numbers on disk. Without them, an update run may use -md5 "on" to match recorded MD5 sums against the current file content on hard disk. This is usually much faster than the default which compares both contents directly.
With mount option -o "sbsector=" on GNU/Linux resp. -s on FreeBSD 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 overwriteable media written by xorriso can tell the sbsectors of their sessions by xorriso option -toc. Used after -commit the following option prints the matching mount command for the newly written session (here for mount point /mnt):
 -mount_cmd "indev" "auto" "auto" /mnt
Options -mount_cmd and -mount are also able to produce the mount commands for older sessions in the table-of-content. E.g. as superuser:
 # osirrox -mount /dev/sr0 "volid" '*2008_12_05*' /mnt

Above example produces a result similar to -root / -old-root / with mkisofs. For getting the session trees accumulated in the new sessions, let all -update commands use a common parent directory and clone it after updating is done:
 -update_r /home/thomas/projects /current/projects \
 -update_r /home/thomas/personal_mail /current/personal_mail \
 -clone /current /"$(date '+%Y_%m_%d_%H%M%S')" \
The cloned tree will have a name like /2011_02_12_155700.

Sessions on multi-session media are separated by several MB of unused blocks. So with small sessions the payload capacity can become substantially lower than the overall media capacity. If the remaining space on a medium does not suffice for the next gap, the drive is supposed to close the medium automatically.

Better do not use your youngest backup for -update_r. 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.

  Restore directory trees from a particular ISO session to disk
This is an alternative to mounting the medium and using normal file operations.
First check which backup sessions are on the medium:
$ xorriso -outdev /dev/sr0 -toc
Then load the desired session and copy the file trees to disk. Enable restoring of ACL, xattr and hard links. Avoid to create /home/thomas/restored without rwx-permission.
$ xorriso -for_backup \
 -load volid 'PROJECTS_MAIL_2008_06_19*' \
 -indev /dev/sr0 \
 -osirrox on:auto_chmod_on \
 -chmod u+rwx / -- \
 -extract /open_source_projects \
          /home/thomas/restored/open_source_projects \
 -extract /personal_mail /home/thomas/restored/personal_mail \
 -rollback_end
The final command -rollback_end prevents an error message about the altered image being discarded.

  Try to retrieve blocks from a damaged medium
$ xorriso -abort_on NEVER -indev /dev/sr0 \
 -check_media time_limit=1800 report=blocks_files \
 data_to="$HOME"/dvd_copy sector_map="$HOME"/dvd_copy.map --
This can be repeated several times, if necessary with -eject or with other -indev drives. See the human readable part of "$HOME"/dvd_copy.map for addresses which can be used on "$HOME"/dvd_copy with mount option -o sbsector= resp. -s.

FILES

  Program alias names:
Normal installation of xorriso creates three links or copies which by their program name pre-select certain settings:
xorrisofs starts xorriso with -as mkisofs emulation.
xorrecord starts xorriso with -as cdrecord emulation.
osirrox starts with -osirrox "on:o_excl_off" which allows to copy files from ISO image to disk and to apply option -mount to one or more of the existing ISO sessions.

  Startup files:
If not -no_rc is given as the first argument then xorriso 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 above, but none of them is required to exist. The line format is described with command -options_from_file.
If mkisofs emulation was enabled by program name "xorrisofs", "mkisofs", "genisoimage", or "genisofs", then afterwards -read_mkisofsrc is performed, which reads .mkisofsrc files. See there.

  Runtime control files:
The default setting of -check_media abort_file= is:
   /var/opt/xorriso/do_abort_check_media

SEE ALSO

For the mkisofs emulation of xorriso
    xorrisofs(1)

For the cdrecord emulation of xorriso
    xorrecord(1)

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

Libreadline, a comfortable input line facility
    readline(3)

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

Other programs which burn sessions to optical media
    growisofs(1), cdrecord(1), wodim(1), cdrskin(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 resp. 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) 2007 - 2012 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
xorriso is in part based on work by Vreixo Formoso who provides libisofs together with Mario Danic who also leads the libburnia team. Thanks to Andy Polyakov who invented emulated growing, to Derek Foreman and Ben Jansens who once founded libburn.
Compliments towards Joerg Schilling whose cdrtools served me for ten years.