lzip/lziprecover
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Merging upstream version 1.25~pre1.

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Signed-off-by: Daniel Baumann <daniel@debian.org>
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Daniel Baumann 2025-02-21 11:33:15 +01:00
parent 8062cdcacd
commit 3e4c2fba01
Signed by: daniel
GPG key ID: FBB4F0E80A80222F
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22
README
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@ -1,11 +1,8 @@
Description
Lziprecover is a data recovery tool and decompressor for files in the lzip
compressed data format (.lz). Lziprecover is able to repair slightly damaged
files (up to one single-byte error per member), produce a correct file by
merging the good parts of two or more damaged copies, reproduce a missing
(zeroed) sector using a reference file, extract data from damaged files,
decompress files, and test integrity of files.
compressed data format (.lz). Lziprecover also provides Forward Error
Correction (FEC) able to repair any kind of file.
Lziprecover can remove the damaged members from multimember files, for
example multimember tar.lz archives.
@ -13,9 +10,6 @@ example multimember tar.lz archives.
Lziprecover provides random access to the data in multimember files; it only
decompresses the members containing the desired data.
Lziprecover facilitates the management of metadata stored as trailing data
in lzip files.
Lziprecover is not a replacement for regular backups, but a last line of
defense for the case where the backups are also damaged.
@ -59,8 +53,8 @@ GNU ddrescue + lziprecover is the recommended option for recovering data
from damaged lzip files.
If a file is too damaged for lziprecover to repair it, all the recoverable
data in all members of the file can be extracted in one step with the
command 'lziprecover -cd --ignore-errors file.lz > file'.
data in all members of the file can be extracted with the command
'lziprecover -cd --ignore-errors file.lz > file'.
When recovering data, lziprecover takes as arguments the names of the
damaged files and writes zero or more recovered files depending on the
@ -70,14 +64,6 @@ files themselves are kept unchanged.
When decompressing or testing file integrity, lziprecover behaves like lzip
or lunzip.
To give you an idea of its possibilities, when merging two copies, each of
them with one damaged area affecting 1 percent of the copy, the probability
of obtaining a correct file is about 98 percent. With three such copies the
probability rises to 99.97 percent. For large files (a few MB) with small
errors (one sector damaged per copy), the probability approaches 100 percent
even with only two copies. (Supposing that the errors are randomly located
inside each copy).
The lziprecover package also includes unzcrash, a program written to test
robustness to decompression of corrupted data, inspired by unzcrash.c from
Julian Seward's bzip2. Type 'make unzcrash' in the lziprecover source