xorrisofs: Jigdo
5.11 Jigdo Template Extraction
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From man genisoimage: "Jigdo is a tool to help in the distribution of
large files like CD and DVD images; see http://atterer.net/jigdo/ for
more details. Debian CDs and DVD ISO images are published on the web in
jigdo format to allow end users to download them more efficiently."
If the use of libjte was enabled at compile time of xorriso, then
'xorrisofs' can produce a .jigdo and a .template file together with a
single-session ISO image. If not, then Jigdo options will cause a
FAILURE event, which normally leads to program abort.
One may determine the ability for Jigdo by:
$ xorrisofs -version 2>&1 | grep '^libjte' && echo YES
The .jigdo file contains checksums and symbolic file addresses. The
.template file contains the compressed ISO image with reference tags
instead of the content bytes of the listed files.
Input for this process are the normal arguments for a 'xorrisofs'
session with no image loaded, and a .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 padding will be
counted as part of the ISO image.
-jigdo-jigdo disk_path
Set the disk_path for the .jigdo file with the checksums and
download addresses for filling the holes in .template.
-jigdo-template disk_path
Set the disk_path for the .template file with the holed and
compressed ISO image copy.
-jigdo-min-file-size size
Set the minimum size for a data file to be listed in the .jigdo
file and being a hole in the .template file. size may be a plain
number counting bytes, or a number with appended letter "k", "m",
"g" to count KiB (1024 bytes), MiB (1024 KiB), or GiB (1024 MiB).
-jigdo-force-md5 disk_path_pattern
adds a regular expression pattern which will get compared with the
absolute disk_path of any data file that was not found in the .md5
list. A match causes a MISHAP event, which normally does not abort
the program run but finally causes a non-zero exit value of the
program.
-jigdo-exclude disk_path_pattern
Add a regular expression pattern which will get compared with the
absolute disk_path of any data file. A match causes the file to
stay in .template in any case.
-jigdo-map To=From
Add a string pair of the form To=From to the parameter list. If a
data file gets listed in the .jigdo file, then it is referred by
the file address from its line in the .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.
-md5-list disk_path
Set the disk_path where to find the .md5 input file.
-jigdo-template-compress "gzip"|"bzip2"
Choose one of "bzip2" or "gzip" for the compression of the template
file. The jigdo file is put out uncompressed.
-checksum_algorithm_iso list_of_names
Choose one or more of "md5", "sha1", "sha256", "sha512" for the
auxiliary "# Image Hex" checksums in the .jigdo file. The
list_of_names may e.g. look like "md5,sha1,sha512". Value "all"
chooses all available algorithms. Note that MD5 stays always
enabled.
-checksum_algorithm_template list_of_names
Choose the algorithms for the "# Template Hex" checksums in the
.jigdo file. The rules for list_of_names are the same as with
-checksum_algorithm_iso.
Info Catalog
xorrisofs: Charset
xorrisofs: Options
xorrisofs: Miscellaneous