Provided by: jigdo-file_0.7.3-5_amd64 bug

NAME

       jigdo-file  -  Prepare  files  for  Jigsaw  Download  (distribution of huge files, e.g. CD
       images).

SYNOPSIS

       jigdo-file   COMMAND
        [ --image=cdrom.iso ] [ --jigdo=cdrom.jigdo ] [ --template=cdrom.template ] [ --force ] [
       MORE OPTIONS ] [ FILES ... | --files-from=f ]
        Common COMMANDs: make-template, make-image, verify

DESCRIPTION

       Jigsaw  Download,  or  short  jigdo,  is  a  scheme developed primarily to make it easy to
       distribute huge filesystem images (e.g.  CD  (ISO9660)  or  DVD  (UDF)  images)  over  the
       internet,  but  it could also be used for other data which is awkward to handle due to its
       size, like audio/video files or large software packages.

       jigdo tries to ensure that the large file (always called image from now on) is  downloaded
       in  small  parts which can be stored on different servers. People who want to download the
       image do so by telling the jigdo(1) (NOT IMPLEMENTED YET) download  tool  to  process  one
       `.jigdo'  file;  using it, jigdo downloads the parts and reassembles the image. jigdo-file
       is used to prepare the files for download.

       What makes jigdo special is that the parts that are used to reconstruct the image can have
       any  size  and content - they only need to be contained in a contiguous region anywhere in
       the image.

       For example, if you wish to distribute an ISO9660 image which contains a  snapshot  of  an
       FTP  server,  you  can instruct jigdo-file to prepare the download data in such a way that
       when people use jigdo to download the image, jigdo actually fetches the  individual  files
       from  the  FTP  server  and  assembles  them into an exact copy of your image - during the
       download! (If the image is not a filesystem dump, you can use split(1) to create the small
       parts that the image will be reassembled from.)

       You are completely free to choose where the individual parts of the image are stored: They
       may  be  in  entirely  different  directories  on  different  servers  (e.g.  because   of
       storage/bandwidth  constraints),  but  this  is  invisible  to the people downloading your
       image. The information about available servers only needs to be added to the `.jigdo' file
       by you before distributing it.

       The  `DETAILS' section below contains technical details on how jigdo works. The `EXAMPLES'
       section lists a number of common scenarios and may help you to get an idea of  what  jigdo
       is useful for.

OPTIONS

       Many  options  are specific to a particular COMMAND; the ones below are general or used by
       several commands. Further options are listed  below  with  the  individual  commands.  All
       options  are  silently  ignored if they are not applicable to the current command. For any
       BYTES parameters to options, you can append one of the letters `k',  `M'  or  `G'  to  the
       amount you specify, to indicate kilobytes, megabytes or gigabytes.

       -h --help
              Output short summary of commands and options.

       -H --help-all
              Output complete summary of commands and options.

       -v --version
              Output program version.

       -i --image=cdrom.iso
              Specify location of the file containing the image. The image is the large file that
              you want to distribute.

       -j --jigdo=cdrom.jigdo
              Specify location of the Jigsaw Download description  file.  The  jigdo  file  is  a
              human-readable file generated by jigdo-file, to which you add information about all
              the servers you are going to upload the files to.  jigdo will download this file as
              the first step of retrieving the image.

       -t --template=cdrom.template
              Specify  location  of the image `template' file. The template file is a binary file
              generated by jigdo-file, it contains information on how to reassemble the image and
              also (in compressed form) all the data from the image which was not found in any of
              the parts.

              Depending on the command, each of these three files is used  sometimes  for  input,
              sometimes for output. If the file is to be used for output for a particular command
              and the output file already exists, jigdo-file exits with an error, unless  --force
              is present.

              In  most  cases,  you  will  only  need to specify one out of -i -j -t, because any
              missing filenames will be deduced from the one you specify. This is done  by  first
              stripping  any  extension  from  the  supplied  name and then appending nothing (if
              deducing --image), `.jigdo' or `.template'.

       -r --report=default|noprogress|quiet|grep
              Control how verbose the program is, and what format the output has:  noprogress  is
              the  same as default except that no `x% done' progress messages are printed.  quiet
              restricts the output to what is absolutely necessary, mostly error messages.   grep
              is  only different from default for the make-template command: It enables output in
              a simple `<offset> <file>' format which is useful when searching for  binary  files
              in other binary files.

       -f --force
              Overwrite existent output files without complaining.

       --no-force
              This is the default. Refuse to overwrite existent output files.

       -c --cache=jigdo-cache.db
              jigdo-file  usually needs to read the entire contents of all the FILES you specify.
              If you use it repeatedly (e.g. because you make a new CD  image  available  daily),
              caching  the  file information will increase the program's speed significantly. The
              cache file is automatically created if it is not yet present. Data is usually  both
              read from and written to it.

       --no-cache
              This is the default. Do not use a cache.

       --cache-expiry=SECONDS
              Set  maximum age of cache entries. Any entries older than this will be removed from
              the cache. The default is 30 days. You can append one of the letters `h', `d', `w',
              `m',  `y'  to  denote hours, days, weeks, months or years, respectively. A value of
              `0' or `off' disables expiry, so that all entries will stay in the  cache  forever.
              See the section `CACHE FILES' below for more information.

       --readbuffer=BYTES
              Set  size  of  internal  buffers.  The  default  is 128k - if you have a fast disc,
              increasing this value may make jigdo-file faster, but in general,  changing  it  is
              not necessary.

       --md5-block-size=BYTES
              Uninteresting  internal  parameter.   Set  size  of  blocks  into  which  files are
              subdivided. The default is 128k. If you change it, any cache file will have  to  be
              regenerated.  Internally, jigdo-file may choose to use a slightly larger or smaller
              value.

       -T --files-from=file
              Read file and directory names from the specified file.  If file is `-', read  names
              from  standard  input.  Each  line in the file is taken as a name, so the names may
              contain spaces, but not newline characters. An empty line causes jigdo-file to stop
              reading from the file.

              find(1)  is  a  powerful tool for generating file lists, but make sure to use `find
              -type f' if possible - otherwise, if you instruct find to output  both  a  filename
              and a symlink to that filename, jigdo-file will read the file contents twice.

       --hex  Output  checksums  in hexadecimal instead of Base64-like format. This should not be
              used with the make-template command, because the resulting `.jigdo'  file  violates
              the `.jigdo' file format. Its intended use is to make jigdo-file more interoperable
              with other Unix shell utilities like md5sum(1).

       --no-hex
              This is the default. Use jigdo's own Base64-like encoding of checksums.

       --debug[=help|=all|=UNIT,~UNIT... ]
              Switch on or off debugging output. Just `--debug' is equivalent  to  `--debug=all'.
              The  argument is a comma-separated list of unit names for which debugging output is
              to be enabled, or disabled if the name is preceded by `~'. The special  name  `all'
              means  all units. By default, debugging output is switched off except for the units
              `assert' and `general'. The exact list of available units for which  debugging  can
              be  switched  on depends on whether jigdo was compiled with debugging support - the
              list can be printed with `--debug=help'.

       FILES  Names of files or directories to use  as  input.  These  are  the  parts  that  are
              contained  in  the  image.  In  case  one  of the names is a directory, the program
              recursively scans the directory and adds all files contained  in  it.  While  doing
              this, it follows symbolic links, but avoids symlink loops.

              If one of the filenames starts with the character `-', you must precede the list of
              files with `--'. A value of `-' has no special meaning in this list, it stands  for
              a file whose name is a single hyphen.

COMMANDS

       The command name is the first non-option argument passed to jigdo-file. Most commands have
       short abbreviations as well as long names. The short command names should not be  used  in
       scripts - there may be incompatible changes to them in the future!

   MAKE-TEMPLATE, MT
       Reads image and FILES, creates `.jigdo' and `.template'. This is the main functionality of
       jigdo-file.

       It is possible to specify both --image=- and --files-from=-. In this case, first the  list
       of  files  is  read  from  standard  input  until an empty line is encountered. Everything
       following it is assumed to be the image data. This can be useful if you use mkisofs(1)  or
       similar  programs  that  can  output  the complete image on their standard output, because
       there is no need to store the image on disc temporarily.

       If a FILES argument contains the characters `//'  (Unix)  or  `\.\'  (Windows),  this  has
       special  meaning.  In  the final jigdo file that users will download, each of the parts is
       referenced in the `[Parts]' section with a URI of  the  form  `Label:some/filename'.  (See
       `FORMAT  OF .JIGDO FILES' below for a detailed description.) The `[Servers]' section gives
       a   mapping   of   labels   to   servers   on    the    internet,    with    lines    like
       `Label=http://myserver.org/jigdofiles/'.  Using  this  information,  jigdo will create the
       final  download  URI   for   the   part,   `http://myserver.org/jigdofiles/some/filename'.
       Specifying  `//'  (or  `\.\') in a file or directory name serves to `cut off' the names at
       the right directory level. For example,  if  the  Unix  path  of  one  of  your  FILES  is
       `/path/some/filename',  you can tell jigdo-file to cut off after the `/path' by passing it
       the argument `/path//some/filename', or `/path//' if you want the whole directory scanned.
       The path names need not be absolute; `somedirectory//' is also possible.

       --label Label=/path
              Specify  a name to use as the label name for a path on disc. (Influences the output
              jigdo file.) If you used `//' in the FILES arguments as described above, jigdo-file
              will  by  default pick label names automatically (`A', `B' etc.). With this option,
              you can give labels more meaningful names. Note that the label name  will  only  be
              used if one or more FILES begin with `/path//'.

              Try  to  use label names that start with uppercase characters, to disambiguate them
              clearly from protocol names like `http', `ftp'.

       --uri Label=http://some.server.org/
              By default, using  --label  as  described  above  will  cause  lines  of  the  form
              `Label=file:/path/'  to  be  written to the `[Servers]' section of the output jigdo
              file.  If  you  want  to  override  the  `file:'  URI  so  that  the   line   reads
              `Label=http://some.server.org/',  you  can  do  so  by  specifying --uri along with
              --label. Giving just --uri Label=... without the  corresponding  --label  Label=...
              has  no  effect,  and  even  if  you  specify  both,  an entry is only added to the
              `[Servers]' section if the label is referenced by at least one `[Parts]' entry.

              The supplied value is not quoted by the program; if it contains characters such  as
              space  or  any of the characters #"'\ then you must quote it.  (Under Unix, you may
              need to quote the value twice to also protect it from the shell, e.g. \\\\ or  '\\'
              to get a single backslash in the URI.)

              The  mapping  specified with an --uri option is ignored if it is already present in
              the output jigdo file.

              Users of the Windows version may notice  that  the  `\'  directory  separators  are
              converted  into `/' in the `file:' URIs that are generated by default. This is done
              to increase cross-platform compatibility of `file:' - the print-missing command  of
              the Windows version will automatically re-convert the characters when it prints the
              URIs. In case you supply your own `file:' URIs under Windows using --uri, you  must
              also exchange `/' and `\'.

       -0 to -9
              Set  amount of compression in the output template file, from -0 (no compression) to
              -9 (maximum compression). The default is -9, which can make the template generation
              quite slow. By default, the compression algorithm used is the same as for gzip(1).

       --gzip and --bzip2
              Choose  between  the  gzip  and  bzip2 compression algorithms. The default is gzip.
              Bzip2 usually gives a better compression ratio, but  compression  is  significantly
              slower than with gzip.

       --min-length=BYTES
              Set  minimum  length  of  a  part  for jigdo-file to look for it in the image.  The
              default is 1k. Parts smaller than this will never be found in the image,  so  their
              data will be included in the template file. The search algorithm used requires such
              a minimum length, otherwise template generation could become extremely slow. If you
              know  for  sure  that  all  your  FILES  are  larger than a certain amount, you can
              increase jigdo-file's speed slightly by specifying the  amount  with  this  option.
              There  is a hard-wired absolute minimum of 256 bytes - anything lower will silently
              be set to 256.

       --merge=FILE
              Include the contents of FILE in the output `.jigdo' file. The file can contain data
              which  you want added to the output (for example, a `[Servers]' section with a list
              of your servers as entries), or it can be the jigdo file output by an  earlier  run
              of jigdo-file.

              It  is possible to specify the same file for input with --merge and for output with
              --jigdo. However, you will also need to use --force to make the  program  overwrite
              the  old  version of the jigdo file with the new one.  FILE can be `-' for standard
              input.

              When adding new information to the supplied file, jigdo-file will  not  insert  new
              lines  into  the  `[Parts]'  section if an entry for the same MD5 checksum (but not
              necessarily with the same URI!) already exists, and it will not  insert  new  lines
              into the `[Servers]' section if a completely identical entry already exists.

              When reading in the existing FILE, the behaviour is slightly different: The program
              preserves entries in the `[Parts]' section with identical checksum,  but  different
              URIs.  For  completely identical entries (same checksum and URI), only one entry is
              preserved  and  the  duplicates  are  removed.  The  `[Servers]'  section  is  left
              untouched.

       --image-section
              This  is the default. Causes jigdo-file to add an `[Image]' section to the `.jigdo'
              file.

              As an exception, a new `[Image]' section is not added if you use  --merge  and  the
              file  to  merge  contains  an  `[Image]' section with a line which reads `Template-
              MD5Sum=' (end of line after the `='). In this case, the generated  template  data's
              MD5  checksum  value  is just added after the `=' of the first line of this form in
              the file - no whole new `[Image]' section is appended.  This  behaviour  is  useful
              because  it  allows  you  to  pass  via --merge an `[Image]' section with arbitrary
              content and then have the MD5  checksum  automatically  added  by  jigdo-file.  The
              section  `FORMAT  OF .JIGDO FILES' below explains the `[Image]' section contents in
              greater detail.

       --no-image-section
              Do not include an `[Image]' section in the `.jigdo'  file.  You  need  to  add  one
              yourself  if you use this option. However, doing that is not easy (you also need to
              add a `Template-MD5Sum' line with the correct checksum, or jigdo will complain), so
              use of this option is discouraged.

       --servers-section
              This is the default. Causes jigdo-file to add a `[Servers]' section to the `.jigdo'
              file. This default section uses `file:' URIs, which allows for immediate reassembly
              of  the image from the local filesystem, and is also useful if you want to edit the
              file manually and replace the `file:' URIs with other URIs.

       --no-servers-section
              Do not add a `[Servers]' section at the end of the `.jigdo' file.  Useful  e.g.  if
              you are going to append the section with a script.

       --match-exec=SHELLCOMMAND
              Whenever  a  file  is  found  in  the image, execute the supplied command string by
              passing it to a shell.  jigdo-file sets up a number of environment  variables  with
              information  about  the  file match. For example, if the file `/path//a/b/file' was
              found in the image and `Label:a/b/file' is going to  be  written  to  the  `.jigdo'
              file:

              · LABEL="Label" - Name of the label for the file. The example assumes that `--label
                Label=/path' was specified by you.  In the absence of such an option, LABEL  will
                be set but empty.

              · LABELPATH="/path/"  - The path corresponding to the label, or in other words, the
                prefix of the matched file's path that will not appear  in  the  output  `.jigdo'
                file. Is set even without any `--label' option present.  Ends with a slash.

              · MATCHPATH="a/b/"  -  The  rest  of  the path, without the leafname of the matched
                file. Is either empty or ends with a slash.

              · LEAF="file" - The leafname of the matched file.

              · MD5SUM="lNVdUSqbo2yqm33webrhnw" - The md5sum of the matched file, in  Base64-like
                format.

              · FILE="/path//a/b/file"  -  For  convenience,  the  complete path of the file. The
                variable is always set to $LABELPATH$MATCHPATH$LEAF.

       Please be careful to correctly quote the string passed  to  this  option,  otherwise  your
       supplied  command  will  not  work  with  filenames that contain spaces. As an example, to
       create a backup of hard links to the matched files, use  the  following  option:  --match-
       exec='mkdir -p "${LABEL:-.}/$MATCHPATH" && ln -f "$FILE" "${LABEL:-.}/$MATCHPATH$LEAF"'

       By  default,  no command is executed. Use --match-exec="" to remove a command string which
       was set with an earlier use of this option.

       --greedy-matching
              This is the default. Imagine that your image contains a .tar  file  which  in  turn
              contains another file x, and that you provide both the .tar and the files inside it
              on the command line. When jigdo-file scans the image, it encounters  the  beginning
              of the .tar file, and then the file x.

              At  this  point,  a decision must be made: Should the smaller file x be recorded as
              matched, or should it be ignored in favour of the larger (and thus better) match of
              the  .tar  file?  Unfortunately,  at  this point it is not clear whether there will
              actually be a full match of the .tar, so by default, the program prefers the  small
              match.

       --no-greedy-matching
              In  the  case  where  a large partial match is present and a shorter match has been
              confirmed, ignore the small match. (See the option above.)

   MAKE-IMAGE, MI
       Reads `.template' and FILES, creates image (or `imagename.tmp').  Provides  a  rudimentary
       way  of  reassembling  images  - jigdo is usually better suited for this task. However, in
       contrast to jigdo, no `.jigdo' file is required.

       If the image is to be written to a file (and not to standard output), it  is  possible  to
       create the image in several steps, with several invocations of `jigdo-file make-image', as
       follows: You first invoke jigdo-file, specifying as many files as are  available  at  this
       time. The program scans the files, and those that are contained in the image are copied to
       a temporary file, whose name is formed by appending `.tmp' to the image filename.

       For all further files which could be parts of the image, you repeat this process. As  soon
       as  all  parts  are present, the temporary file will be truncated slightly (to delete some
       administrative data that jigdo-file appends at the end) and renamed  to  the  final  image
       name.  The possibility of reassembling the image in several steps is especially useful for
       gathering files from removable media, e.g. several older CDs.

       Scripts using make-image can detect whether image creation is  complete  by  checking  the
       exit  status:  0  signals  successful creation, whereas 1 means that more files need to be
       supplied. Other errors result in an exit status of 2 (`recoverable', e.g. file not  found)
       or 3 (non-recoverable, e.g.  write error).

       --check-files
              This  is  the  default.  Whenever  any  part  is  copied to the image, re-check its
              checksum against the checksum stored in the template. It is  recommended  that  you
              leave this switched on, even if it slows down image creation a bit.

       --no-check-files
              Do  not  check  files' checksums when copying them to the image. This can be safely
              used when no cache file is used (which means that files  will  be  written  to  the
              image immediately after being scanned) or the whole image is checked later with the
              verify command.

   PRINT-MISSING, PM
       Reads `.jigdo', `.template' and (if present) `imagename.tmp', outputs a list of URIs still
       needed to completely reassemble the image.

       Together  with the make-image command, this provides most of the functionality of jigdo on
       the command line.

       For each part that is not yet present in the temporary image file, the  file  checksum  is
       looked up in the `[Parts]' section of the jigdo file. Any label in the corresponding entry
       is then expanded according to the label definitions in the `[Servers]' section and printed
       on  standard  output.  jigdo  allows you to specify several alternative locations for each
       label in this section, but print-missing will only output the first one for  each  missing
       part.

       If  the  checksum  cannot be found in the `[Parts]' section (this Should Not Happen unless
       you deleted that section), a lookup is instead made  for  `MD5Sum:<checksum>',  just  like
       with  jigdo.  (Thus, if you want to get rid of the `[Parts]' section, you can do so if you
       rename each part to its own checksum.)

       --uri Label=http://some.server.org/
              Override the entries in the `.jigdo' file for any label with a URI of your  choice.
              With  the  example above, a `[Parts]' entry of `Label:some/filename' will cause the
              line `http://some.server.org/some/filename' to be printed.

              The supplied value is not quoted by the program; if it contains characters such  as
              space  or  any of the characters #"'\ then you must quote it.  (Under Unix, you may
              need to quote the value twice to also protect it from the shell, e.g. \\\\ or  '\\'
              to get a single backslash in the URI.)

   PRINT-MISSING-ALL, PMA
       Just  like  print-missing,  this command outputs a list of URIs still needed to completely
       reassemble the image. However, all alternative download locations are printed  instead  of
       just  one.  In  the  output, the URIs for a file are separated from other files' URIs with
       blank lines. The --uri option has the same effect as for print-missing.

   VERIFY, VER
       Reads image (presumably generated with make-image) and  `.template',  checks  for  correct
       checksum of image.

       The template data does not only contain checksums of the individual parts, but also of the
       image as a whole.  make-image already performs a number of internal  checks,  but  if  you
       like, you can additionally check the image with this command.

   SCAN, SC
       Reads  all  the  FILES and enters them into the cache, unless they are already cached. The
       --cache option must be present for this command.

       --no-scan-whole-file
              This is the default. This only causes the first --md5-block-size bytes of each file
              to  be  read.  If the cache is used later by jigdo-file make-image, the rest of the
              file will be read once these first bytes are recognized in the input image.

       --scan-whole-file
              Immediately read the entire file contents and store them in the cache.

   MD5SUM, MD5
       Reads all the FILES and prints out MD5 checksums of their contents. This command is  quite
       similar to md5sum(1), except that the checksum is output in the Base64-like encoding which
       is also used elsewhere by jigdo-file.

       The FILES arguments are processed in the same way as with the other commands, which  means
       that  recursion automatically takes place for any arguments that are directories, and that
       symbolic links are not listed except when the file(s) they  point  to  are  not  reachable
       directly.

       In  the  checksum list printed on standard output, only the part of the filename following
       any `//' (or `\.\' on Windows) is printed. Any --cache will be used  for  querying  files'
       MD5 checksums and/or writing the checksums of scanned files.

   LIST-TEMPLATE, LS
       Reads  a  `.template' file and outputs low-level information about the image and all parts
       contained in it, including offset, length and checksum.

       You can also use this command with temporary image files  (by  specifying  something  like
       --template=imagename.tmp) - in that case, the output also distinguishes between parts that
       have been written to the image and parts that haven't.

       The exact output format may change incompatibly  between  different  jigdo  releases.  The
       following  different  types  of  lines  can  be output. `have-file' only occurs for `.tmp'
       files, indicating a file that has already been successfully written to the temporary file:

       in-template offset-in-image length
       need-file offset-in-image length file-md5sum filestart-rsyncsum
       have-file offset-in-image length file-md5sum filestart-rsyncsum
       image-info image-length image-md5sum rsyncsum-size

DETAILS

       Jigsaw Download was created with the format of ISO9660 CD images in mind  -  however,  the
       following  also applies to many other filesystem formats, as well as to `tar' archives and
       uncompressed `zip' archives. A CD image  contains  both  information  for  organizing  the
       filesystem (header with disc name etc., ISO9660 directory data, data of extensions such as
       Joliet or RockRidge, zero padding) and  the  files  contained  on  the  CD.  An  important
       property that jigdo relies on is that each file is stored in one contiguous section of the
       image; it is not split into two or more parts.

       When jigdo-file is given a number of files that might be contained in an image, it detects
       whether  any  of the files are present using a `rolling checksum' inspired by the one used
       by rsync(1). The resulting data is written to the `.template' file: If a  section  of  the
       image could not be matched (e.g. it was directory information), the data is compressed and
       written directly to the template. However, if a matching  file  was  found,  its  data  is
       omitted  from  the  template.  Instead,  only a reference (an MD5 checksum of the file) is
       inserted in the template.

       Note that the template data only contains binary data, it does not contain  any  filenames
       or  URIs, since it cannot be easily edited in case any of these values need to be changed.
       All that information is stored in the `.jigdo' file, a text file to which you can add URLs
       for your server(s). The jigdo file provides a mapping for each MD5 checksum to one or more
       alternative download locations for the corresponding part.

       Apart from the mapping of MD5 sums to URIs, the jigdo file also contains an  URI  pointing
       to a download location for the template file. This way, the jigdo download tool only needs
       to be given one URI (that of the `.jigdo' file) to be able to download and reassemble  the
       complete image.

FORMAT OF .JIGDO FILES

       The  overall  format  of  `.jigdo' files follows that of `.ini' files, as also used by the
       Gnome and KDE projects for some data. The file is organized into sections, each  of  which
       is  preceded  by  a line reading `[Sectionname]'. Within each section, lines have the form
       `Label=Value'. Such lines are also called `entries' below. All `.jigdo' files use UTF-8 as
       their character encoding.

       Comments  are  introduced  with  the  `#'  character  and  extend  to the end of the line.
       Whitespace is ignored at line start and end as well as to the left and  right  of  section
       names  and  the  `=' in entries. Furthermore, the jigdo utilities split up the text of the
       entry value (i.e. the part after the `=') into whitespace-separated words, much  like  the
       Unix  shell.  Single  ''  and  double  ""  quotes  can  be  used to prevent that e.g. URIs
       containing whitespace are split apart. Similarly, characters  with  special  meaning  (the
       characters  '"#\  and space/tab) must be quoted with \ to appear in the value. As with the
       shell, there is a difference between ' ' and " ": Within  '  ',  the  characters  "#\  and
       whitespace  lose their special meaning and become ordinary characters, whereas within " ",
       only the characters '# and whitespace  lose  their  special  meaning  -  in  other  words,
       backslash escapes still work inside " ", but not ' '.

       `.jigdo'  files  can  optionally  be  compressed  with  gzip(1). jigdo-file always outputs
       uncompressed  files,  which  you  can  compress  yourself.   jigdo-lite  supports   single
       uncompressed and compressed files.

       (Behaviour  which  may  change  in  the  future and which should not be relied upon: jigdo
       additionally supports any number of concatenated plaintext and gzipped parts in the  files
       -  for  example,  you  can  compress  a  `.jigdo'  file  and then add a couple of lines of
       uncompressed data to the end.)

       In all cases, the `.gz' extension should be removed from the filename  -  the  tools  will
       determine automatically from the file contents whether a file is compressed or not.

       Below is a description of the individual section names used by jigdo.

   JIGDO SECTION
       [Jigdo]
       Version=1.1
       Generator=jigdo-file/1.0.0

       Information  about  the  version  of  the  jigdo  file  format  used, and the program that
       generated it. There should be one such section per `.jigdo' file.

   IMAGE SECTION
       [Image]
       Filename="filename for saving on user's disc"
       Template="URI where to fetch template file"
       Template-MD5Sum=OQ8riqT1BuyzsrT9964A7g
       ShortInfo=single-line description of the image (200 characters max.)
       Info=long description (5000 characters max.)

       The value for the `Template' entry can be either an URL (absolute or relative to  the  URL
       of  the jigdo file) or a string of the form `Label:pathname' (UNIMPLEMENTED), as described
       below.

       The `Template-MD5Sum' entry is added by jigdo-file and specifies the MD5 checksum  of  the
       generated  `.template'  file.  It  is  used  by jigdo to detect cases where the downloaded
       template data is corrupted or belongs to a different image.

       Unlike other entry values, the values of the `ShortInfo' and `Info' entries are not  split
       up into words, instead all quoting is preserved.

       The  value of the `Info' entry is special in that jigdo(1) can optionally parse XML markup
       it contains. If the markup has errors such as unbalanced/unsupported tags, the  string  is
       displayed  literally,  without  XML  parsing.  Supported  tags are <b></b> (bold), <i></i>
       (italic), <tt></tt> (typewriter font), <u></u>  (underline),  <big></big>  (larger  font),
       <small></small>  (smaller  font)  and  <br/>  (linebreak). Supported entities include &lt;
       (`<'), &gt; (`>') and &amp; (`&'). Note that the whole `Info' entry must be on one line in
       the jigdo file.

       This  section may occur multiple times, but all except the first one will be ignored. This
       is useful e.g. when creating a `.jigdo' file  for  a  DVD  image  when  you  already  have
       `.jigdo'  files  for CDs with the same content: You can simply `[Include]' (see below) the
       CDs' jigdo files at the end of the DVD jigdo file, after its `[Image]' section.

   PARTS SECTION
       [Parts]
       xJNkjrq8NYMraeGavUpllw=LabelA:part0
       GoTResP2EC6Lb_2wTsqOoQ=LabelA:part1
       kyfebwu6clbYqqWUdFIyaw=LabelB:some/path/part2
       -J9UAimo0Bqg9c0oOXI1mQ=http://some.where.com/part3

       All lines in the section, which provides the mapping from MD5 checksums to URIs, have  the
       same  format:  On  the  left  side  of  the  `='  the checksum (encoded with a Base64-like
       encoding) is given, and on the  right  a  string  corresponding  to  the  part  with  this
       checksum;  either  a  complete  URI  or  a  string  of the form `Label:pathname', which is
       expanded into one or more URIs by looking up  the  definition(s)  for  the  Label  in  the
       `[Servers]' section.

       In  case  a particular MD5 checksum cannot be found in any `[Parts]' section by jigdo, the
       program    will    perform    a    lookup    for     `MD5Sum:<checksum>',     e.g.     for
       `MD5Sum:xJNkjrq8NYMraeGavUpllw' if you deleted the line for `part0' above.

       A  checksum  appearing  multiple  times  in  this  section  indicates alternative download
       locations for the part.

       There may be any number of `[Parts]' sections in the file; they are  all  considered  when
       looking up MD5 checksums.

       jigdo-file  always  puts  the  `[Parts]'  section  at  the  end  of  the file, and it even
       rearranges any file specified with --merge to have only one such section at the end.  This
       is  done  to  allow  jigdo to display the information from the `[Image]' section while the
       rest of that file is still being downloaded.

   SERVERS SECTION
       [Servers]
       LabelA=http://myserver.org/
       LabelA=ftp://mirror.myserver.org/
       LabelB=LabelC:subdirectory/
       LabelC=http://some.where.com/jigdo/

       All lines in the section,  which  provides  the  mapping  from  server  labels  to  server
       locations,  have the same format: On the left side of the `=' the label name is given, and
       on the right the value to expand the label name to.

       A label name appearing multiple times  in  this  section  indicates  alternative  download
       locations  for  the parts that use the label in the `[Parts]' section. This notation makes
       it very easy to add mirrors to the jigdo file.

       As shown by the example above, the label values may themselves reference other labels.  In
       this  case,  the  entry  `LabelB:some/path/part2'  in the `[Parts]' section will expand to
       `http://some.where.com/jigdo/subdirectory/some/path/part2'.    Loops    in    the    label
       definitions result in undefined behaviour and must be avoided.

       There  may be any number of `[Servers]' sections in the file; they are all considered when
       looking up labels. Either of `[Parts]' or `[Servers]', but not both, can be  omitted  from
       the jigdo file.

   COMMENT SECTION
       [Comment]
       Any text, except that lines must not begin with `['.

       All  text following a `[Comment]' or `[comment]' line is ignored, up to the next line with
       a section label.

   INCLUDE DIRECTIVE
       [Include http://some.url/file.jigdo]

       Lines of this form cause the content of the specified jigdo  file  to  be  downloaded  and
       parsed  just like the main jigdo file. The effect will be the same as copying the included
       file's contents into the file  which  contains  the  include  directive.  (Exception:  Any
       relative  URLs  are  always resolved using the URL of the `.jigdo' file that contains that
       relative URL.)

       The URL argument can be an absolute or relative URL.  Relative  URLs  are  assumed  to  be
       relative  to  the URL of the jigdo file which contains the include directive. Includes can
       be nested, but it is an error to create a loop of include directives. It is  not  possible
       to use URLs of the form `Label:pathname'.

       The  URL  cannot  be quoted with "". Any `]' characters in the argument must be escaped as
       `%5D', and any spaces as `%20'.

       Include directives are only supported by jigdo, they are ignored by jigdo-lite.

       An include directive terminates any previous section, but it does not start a new one.  In
       other  words,  a new section must always be started after the include line, jigdo does not
       allow normal entries to appear below the `[Include]'.

CACHE FILES

       Any file specified with the --cache option is used to store information  about  the  FILES
       presented  to jigdo-file. When querying the cache, a file is considered unchanged (and the
       cached data is used) only if filename, file size and last modification time (mtime)  match
       exactly.  For  the  filename  match,  not  the entire file name is used, but only the part
       following any `//', so that any changes to the part before the `//'  will  not  invalidate
       the cache.

       Old cache entries are removed from the cache if they have not been read from or written to
       for the amount of time specified with --cache-expiry. Entries are not immediately  removed
       from  the  cache  if  the  file they refer to no longer exists - this makes it possible to
       cache information about files on removable media.

       Cache expiry only takes place after jigdo-file has done its main work - if any old entries
       are accessed before expiry takes place, they will be kept.  For example, if the program is
       run using the default expiry time of 30 days, but  accesses  a  cache  file  with  entries
       generated  2  months  ago,  then  entries in that cache will be considered, and only those
       cache entries that were not needed during the program run will be expired.

       Due to a peculiarity of the  underlying  database  library  (libdb3),  cache  files  never
       shrink,  they only grow. If a large number of entries was expired from your cache file and
       you want it to shrink, you can either just delete it (of course then everything will  have
       to  be  regenerated)  or  use  the  utilities  accompanying libdb3 to dump and restore the
       database, with a command like `db3_dump old-cache.db | db3_load new-cache.db'. For Debian,
       these programs are supplied in the package `libdb3-util'.

       If  a  different  --md5-block-size  is  specified,  the entire file needs to be re-read to
       update its cache  entry.  If  a  different  --min-length  is  specified,  only  the  first
       `md5-block-size' bytes of the file need to be re-read.

EXAMPLES

   PREPARING YOUR CD IMAGE FOR DISTRIBUTION
       You  have  created  a  CD image `image.iso' from some of the files stored in the directory
       `/home/ftp' on your harddisc, which is also available online  as  `ftp://mysite.org'.   As
       you don't want to waste space by effectively hosting the same data twice (once as files on
       the FTP server, once inside the image), and you are fed up with users' downloads  aborting
       after  200MB  and  their restarting the download dozens of times, you decide to use jigdo.
       How do you prepare the image for download?

       In fact, only one command is necessary:

              jigdo-file    make-template     --image=image.iso     --jigdo=/home/ftp/image.jigdo
              --template=/home/ftp/image.template   /home/ftp//  --label  Mysite=/home/ftp  --uri
              Mysite=ftp://mysite.org/

       People can now point jigdo at `ftp://mysite.org/image.jigdo' to download your  image.  The
       template file needs to be accessible as `ftp://mysite.org/image.template'.

       Note  that  nothing  prevents  you  from  doing  the  same  for  an  FTP server that isn't
       administrated by you - in that case, you only need to host the  `.jigdo'  and  `.template'
       files on your own server/homepage.

   PREPARING AN ARBITRARY LARGE FILE FOR DISTRIBUTION
       We  assume that you have a large file that is not a filesystem, e.g. `movie.mpeg'. Because
       of space problems, you want to distribute the data on two servers.

       In this case, the parts of the image need to be  generated  artificially  with  the  split
       command.  For  example,  to  create chunks of 4MB each, use `split -b 4m movie.mpeg part'.
       Copy the resulting files `partXX' into two  directories  `1'  and  `2'  that  you  create,
       according  to  how  you  want  the files distributed between the servers. Next, create the
       jigdo and template files with `jigdo-file make-template --image=movie.mpeg 1//  2//'.  You
       will  need  to  edit the `.jigdo' file and provide the right URIs for the two servers that
       you are going to upload the `partXX' files to.

   CUSTOMIZED VERSIONS OF IMAGES
       Because it is possible to assign a different URI for each part of an image  if  necessary,
       jigdo  is  very  flexible.  Only  one example is the possibility of customized versions of
       images: Suppose that someone is distributing a CD image, and that you want to make  a  few
       small  changes to it and redistribute your own version. You download the `official.iso' CD
       image with jigdo (passing it the URL of `official.jigdo'), write it  to  CD-R,  make  your
       changes (say, adding files from the `myfiles' directory on your harddisc) and produce your
       own version, `myversion.iso'.  Next, you instruct  jigdo-file  to  create  the  jigdo  and
       template files for your modified image, using the command

              jigdo-file   make-template   --image=myversion.iso  /mnt/cdrom/  myfiles//  --label
              My=myfiles/ --uri My=http://my.homepage.net/ --merge=official.jigdo
       while `official.iso' is mounted under `/mnt/cdrom'. By using --merge, you have told jigdo-
       file  to  take  the  contents  of  `official.jigdo', add to it a new `[Image]' section for
       `myversion.iso' and  write  the  resulting  jigdo  file  to  `myversion.jigdo'  -  so  now
       `myversion.jigdo'  offers  two images for download, the original version and your modified
       version. (If you do not want it to offer the official version,  edit  it  and  remove  the
       `[Image]' section that lists `official.iso'.)

       Now you can upload the `.jigdo' file, the `.template' file and also the files in `myfiles'
       to `http://my.homepage.net/'.  Thus, for people to download your modified  image,  you  do
       not need to upload the complete image contents to your web space, but only the changes you
       made!

       (In case you only made very few changes, you could also omit the  `myfiles'  parameter  in
       the command above, then all your changes end up in the new template file.)

   COMBINING MANY JIGDO-MANAGED IMAGES INTO ONE
       It is also no problem to combine data from several sources that use jigdo. For example, if
       of five different and unrelated servers each one distributes  a  different  CD  image  via
       jigdo,  you  can  create a customized DVD image that contains the data from all these CDs.
       When people use jigdo to download your image, the individual files on the DVD are  fetched
       from the same sources as the original CDs.

       Consequently,  even  though  you will be distributing a 3.2GB file via your web space, the
       actual amount of data that is stored on your server will only be in the order  of  several
       MBs.

BUGS

       For  certain  contents  of  one  of the input files, most notably a sequence of zero bytes
       longer than --min-length at the start of the file and an area of zeros preceding the  file
       data  in  the  image,  jigdo-file  make-template  may  fail to find the file in the image.
       Unfortunately, this restriction cannot be avoided because the program  could  become  very
       slow  otherwise.  If  you  use  the --debug option, all instances of jigdo-file discarding
       possible matches are indicated by lines containing the word `DROPPED'.

       In fact, not only all-zeroes files trigger this behaviour, but also files which contain at
       their  start  a  long  sequence  of  short  identical  strings.  For  example, both a file
       containing only `a' characters and one containing `abcabcabcabc...' are problematic.

SEE ALSO

       jigdo(1)  (NOT  YET  IMPLEMENTED),  jigdo-lite(1),  jigdo-mirror(1),  split(1)  (or  `info
       split'), find(1) (or `info find'), mkisofs(1), md5sum(1)

AUTHOR

       Jigsaw  Download  <URL:http://atterer.org/jigdo/>  was  written  by Richard Atterer <jigdo
       atterer.org>, to make downloading of CD ROM images for the Debian Linux distribution  more
       convenient.

                                           19 May 2006                              JIGDO-FILE(1)