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-rw-r--r--doc/plzip.texi64
1 files changed, 44 insertions, 20 deletions
diff --git a/doc/plzip.texi b/doc/plzip.texi
index c459cde..5f32f6e 100644
--- a/doc/plzip.texi
+++ b/doc/plzip.texi
@@ -6,8 +6,8 @@
@finalout
@c %**end of header
-@set UPDATED 14 May 2016
-@set VERSION 1.5
+@set UPDATED 12 April 2017
+@set VERSION 1.6
@dircategory Data Compression
@direntry
@@ -48,7 +48,7 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}).
@end menu
@sp 1
-Copyright @copyright{} 2009-2016 Antonio Diaz Diaz.
+Copyright @copyright{} 2009-2017 Antonio Diaz Diaz.
This manual is free documentation: you have unlimited permission
to copy, distribute and modify it.
@@ -90,10 +90,10 @@ including error-checked merging of damaged copies of a file.
@item
The lzip format is as simple as possible (but not simpler). The lzip
-manual provides the code of a simple decompressor along with a detailed
-explanation of how it works, so that with the only help of the lzip
-manual it would be possible for a digital archaeologist to extract the
-data from a lzip file long after quantum computers eventually render
+manual provides the source code of a simple decompressor along with a
+detailed explanation of how it works, so that with the only help of the
+lzip manual it would be possible for a digital archaeologist to extract
+the data from a lzip file long after quantum computers eventually render
LZMA obsolete.
@item
@@ -146,6 +146,10 @@ or more compressed files. The result is the concatenation of the
corresponding uncompressed files. Integrity testing of concatenated
compressed files is also supported.
+LANGUAGE NOTE: Uncompressed = not compressed = plain data; it may never
+have been compressed. Decompressed is used to refer to data which have
+undergone the process of decompression.
+
@node Invoking plzip
@chapter Invoking plzip
@@ -220,6 +224,20 @@ Force re-compression of files whose name already has the @samp{.lz} or
@itemx --keep
Keep (don't delete) input files during compression or decompression.
+@item -l
+@itemx --list
+Print the uncompressed size, compressed size and percentage saved of the
+specified file(s). Trailing data are ignored. The values produced are
+correct even for multimember files. If more than one file is given, a
+final line containing the cumulative sizes is printed. With @samp{-v},
+the dictionary size, the number of members in the file, and the amount
+of trailing data (if any) are also printed. With @samp{-vv}, the
+positions and sizes of each member in multimember files are also
+printed. @samp{-lq} can be used to verify quickly (without
+decompressing) the structural integrity of the specified files. (Use
+@samp{--test} to verify the data integrity). @samp{-alq} additionally
+verifies that none of the specified files contain trailing data.
+
@item -m @var{bytes}
@itemx --match-length=@var{bytes}
Set the match length limit in bytes. After a match this long is found,
@@ -267,8 +285,9 @@ is affected at compression time by the choice of dictionary size limit.
Check integrity of the specified file(s), but don't decompress them.
This really performs a trial decompression and throws away the result.
Use it together with @samp{-v} to see information about the file(s). If
-a file fails the test, plzip may be unable to check the rest of the
-files.
+a file does not exist, can't be opened, or is a terminal, plzip
+continues checking the rest of the files. If a file fails the test,
+plzip may be unable to check the rest of the files.
@item -v
@itemx --verbose
@@ -469,9 +488,6 @@ times the data size. Default is 136 MiB.
For decompression of a regular (seekable) file to another regular file,
or for testing of a regular file; the dictionary size.
-(Note that regular files with more than 1024 bytes of trailing data are
-treated as non-seekable).
-
@item
For testing of a non-seekable file or of standard input; the dictionary
size plus up to 5 MiB.
@@ -526,20 +542,24 @@ data size for each level:
@chapter Extra data appended to the file
@cindex trailing data
-Sometimes extra data is found appended to a lzip file after the last
+Sometimes extra data are found appended to a lzip file after the last
member. Such trailing data may be:
@itemize @bullet
@item
Padding added to make the file size a multiple of some block size, for
-example when writing to a tape.
+example when writing to a tape. It is safe to append any amount of
+padding zero bytes to a lzip file.
@item
-Garbage added by some not totally successful copy operation.
+Useful data added by the user; a cryptographically secure hash, a
+description of file contents, etc. It is safe to append any amount of
+text to a lzip file as long as the text does not begin with the string
+"LZIP", and does not contain any zero bytes (null characters). Nonzero
+bytes and zero bytes can't be safely mixed in trailing data.
@item
-Useful data added by the user; a cryptographically secure hash, a
-description of file contents, etc.
+Garbage added by some not totally successful copy operation.
@item
Malicious data added to the file in order to make its total size and
@@ -554,8 +574,12 @@ integrity information itself. Therefore it can be considered to be below
the noise level.
@end itemize
+Trailing data are in no way part of the lzip file format, but tools
+reading lzip files are expected to behave as correctly and usefully as
+possible in the presence of trailing data.
+
Trailing data can be safely ignored in most cases. In some cases, like
-that of user-added data, it is expected to be ignored. In those cases
+that of user-added data, they are expected to be ignored. In those cases
where a file containing trailing data must be rejected, the option
@samp{--trailing-error} can be used. @xref{--trailing-error}.
@@ -620,8 +644,8 @@ plzip -c /dev/sdc > file.lz
@sp 1
@anchor{concat-example}
@noindent
-Example 6: The right way of concatenating compressed files.
-@xref{Trailing data}.
+Example 6: The right way of concatenating the decompressed output of two
+or more compressed files. @xref{Trailing data}.
@example
Don't do this