* doc/gzip.texi: Fix off-by-one timestamp.

[debian/gzip] / doc / gzip.texi

diff --git a/doc/gzip.texi b/doc/gzip.texi
index 5754aae8cb5c37c72b4bb4cf433dce30c2f2968e..478c4e40ab5ee23caed95605cef025a6ea7906cf 100644 (file)
--- a/doc/gzip.texi
+++ b/doc/gzip.texi
@@ -12,8 +12,8 @@ This manual is for GNU Gzip
 (version @value{VERSION}, @value{UPDATED}),
 and documents commands for compressing and decompressing data.
 
-Copyright @copyright{} 1998-1999, 2001-2002, 2006-2007, 2009-2015
-Free Software Foundation, Inc.
+Copyright @copyright{} 1998-1999, 2001-2002, 2006-2007, 2009-2016 Free Software
+Foundation, Inc.
 
 Copyright @copyright{} 1992, 1993 Jean-loup Gailly
 
@@ -83,7 +83,7 @@ Free Documentation License''.
 @command{gzip} reduces the size of the named files using Lempel--Ziv coding
 (LZ77).  Whenever possible, each file is replaced by one with the
 extension @samp{.gz}, while keeping the same ownership modes, access and
-modification times.  (The default extension is @samp{-gz} for @abbr{VMS},
+modification times.  (The default extension is
 @samp{z} for @abbr{MSDOS}, @abbr{OS/2} @abbr{FAT} and Atari.)
 If no files are specified or
 if a file name is @file{-}, the standard input is compressed to the standard
@@ -104,7 +104,7 @@ the compressed file.  These are used when decompressing the file with the
 truncated or when the time stamp was not preserved after a file
 transfer.  However, due to limitations in the current @command{gzip} file
 format, fractional seconds are discarded.  Also, time stamps must fall
-within the range 1970-01-01 00:00:00 through 2106-02-07 06:28:15
+within the range 1970-01-01 00:00:01 through 2106-02-07 06:28:15
 @abbr{UTC}, and hosts whose operating systems use 32-bit time
 stamps are further restricted to time stamps no later than 2038-01-19
 03:14:07 @abbr{UTC}.  The upper bounds assume the typical case
@@ -203,7 +203,9 @@ Mandatory arguments to long options are mandatory for short options too.
   -N, --name        save or restore the original name and time stamp
   -q, --quiet       suppress all warnings
   -r, --recursive   operate recursively on directories
+      --rsyncable   make rsync-friendly archive
   -S, --suffix=SUF  use suffix SUF on compressed files
+      --synchronous synchronous output (safer if system crashes, but slower)
   -t, --test        test compressed file integrity
   -v, --verbose     verbose mode
   -V, --version     display version number
@@ -359,6 +361,13 @@ specified on the command line are directories, @command{gzip} will descend
 into the directory and compress all the files it finds there (or
 decompress them in the case of @command{gunzip}).
 
+@item --rsyncable
+Cater better to the @command{rsync} program by periodically resetting
+the internal structure of the compressed data stream.  This lets the
+@code{rsync} program take advantage of similarities in the uncompressed
+input when synchronizing two files compressed with this flag.  The cost:
+the compressed output is usually about one percent larger.
+
 @item --suffix @var{suf}
 @itemx -S @var{suf}
 Use suffix @var{suf} instead of @samp{.gz}.  Any suffix can be
@@ -374,6 +383,16 @@ gunzip -S "" *        (*.* for MSDOS)
 Previous versions of gzip used the @samp{.z} suffix.  This was changed to
 avoid a conflict with @command{pack}.
 
+@item --synchronous
+Use synchronous output, by transferring output data to the output
+file's storage device when the file system supports this.  Because
+file system data can be cached, without this option if the system
+crashes around the time a command like @samp{gzip FOO} is run the user
+might lose both @file{FOO} and @file{FOO.gz}; this is the default with
+@command{gzip}, just as it is the default with most applications that
+move data.  When this option is used, @command{gzip} is safer but can
+be considerably slower.
+
 @item --test
 @itemx -t
 Test.  Check the compressed file integrity.
@@ -488,10 +507,6 @@ export PATH=/usr/bin
 exec gzip -9 "$@@"
 @end example
 
-On @abbr{VMS}, the name of the obsolescent environment variable is
-@env{GZIP_OPT}, to avoid a conflict with the symbol set for invocation
-of the program.
-
 @node Tapes
 @chapter Using @command{gzip} on tapes
 @cindex tapes