X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=gzip.1;fp=gzip.1;h=e6aa278cd2282fd8c4e22d2eee35437f45e5e833;hb=20fcfc81ece044b8b0a6768ec6cf47be4e22a2e6;hp=71e097cefc04feb33d3dc44c59bf7f8058e1cf73;hpb=d57728a6ca2413a7c564d8b7bb13d9e5a5a180f3;p=debian%2Fgzip

diff --git a/gzip.1 b/gzip.1
index 71e097c..e6aa278 100644
--- a/gzip.1
+++ b/gzip.1
@@ -296,6 +296,12 @@ are transferred to other systems.
 When decompressing, add .suf to the beginning of the list of
 suffixes to try, when deriving an output file name from an input file name.
 .TP
+.B --synchronous
+Use synchronous output.  With this option,
+.I gzip
+is less likely to lose data during a system crash, but it can be
+considerably slower.
+.TP
 .B \-t --test
 Test. Check the compressed file integrity.
 .TP
@@ -322,6 +328,11 @@ indicates the slowest compression method (best compression).
 The default compression level is
 .BR \-6
 (that is, biased towards high compression at expense of speed).
+.TP
+.B \-\-rsyncable
+When you synchronize a compressed file between two computers, this option allows rsync to transfer only files that were changed in the archive instead of the entire archive.
+Normally, after a change is made to any file in the archive, the compression algorithm can generate a new version of the archive that does not match the previous version of the archive. In this case, rsync transfers the entire new version of the archive to the remote computer.
+With this option, rsync can transfer only the changed files as well as a small amount of metadata that is required to update the archive structure in the area that was changed.
 .SH "ADVANCED USAGE"
 Multiple compressed files can be concatenated. In this case,
 .I gunzip
@@ -364,17 +375,36 @@ such as tar or zip. GNU tar supports the -z option to invoke gzip
 transparently. gzip is designed as a complement to tar, not as a
 replacement.
 .SH "ENVIRONMENT"
-The environment variable
+The obsolescent environment variable
 .B GZIP
 can hold a set of default options for
 .IR gzip .
-These options are interpreted first and can be overwritten by
-explicit command line parameters. For example:
-      for sh:    GZIP="-8v --name"; export GZIP
-      for csh:   setenv GZIP "-8v --name"
-      for MSDOS: set GZIP=-8v --name
+These options are interpreted first and can be overwritten by explicit
+command line parameters.  As this can cause problems when using
+scripts, this feature is supported only for options that are
+reasonably likely to not cause too much harm, and
+.I gzip
+warns if it is used.
+This feature will be removed in a future release of
+.IR gzip .
+.PP
+You can use an alias or script instead.  For example, if
+.I gzip
+is in the directory
+.B /usr/bin
+you can prepend
+.B $HOME/bin
+to your
+.B PATH
+and create an executable script
+.B $HOME/bin/gzip
+containing the following:
+
+      #! /bin/sh
+      export PATH=/usr/bin
+      exec gzip \-9 "$@"
 
-On Vax/VMS, the name of the environment variable is GZIP_OPT, to
+On VMS, the name of the obsolescent environment variable is GZIP_OPT, to
 avoid a conflict with the symbol set for invocation of the program.
 .SH "SEE ALSO"
 znew(1), zcmp(1), zmore(1), zforce(1), gzexe(1), zip(1), unzip(1), compress(1)
@@ -418,7 +448,7 @@ than the decompress code on this machine.
 Recompress the file with gzip, which compresses better and uses
 less memory.
 .TP
-\fIfile\fP\^: already has .gz suffix -- no change
+\fIfile\fP\^: already has .gz suffix -- unchanged
 The file is assumed to be already compressed.
 Rename the file and try again.
 .TP
@@ -454,17 +484,8 @@ read and the whole block is passed to
 for decompression,
 .I gunzip
 detects that there is extra trailing garbage after the compressed data
-and emits a warning by default. You have to use the --quiet option to
-suppress the warning. This option can be set in the
-.B GZIP
-environment variable as in:
-  for sh:  GZIP="-q"  tar -xfz --block-compress /dev/rst0
-  for csh: (setenv GZIP -q; tar -xfz --block-compr /dev/rst0
-
-In the above example, gzip is invoked implicitly by the -z option of
-GNU tar. Make sure that the same block size (-b option of tar) is used
-for reading and writing compressed data on tapes.  (This example
-assumes you are using the GNU version of tar.)
+and emits a warning by default.  You can use the --quiet option to
+suppress the warning.
 .SH BUGS
 The gzip format represents the input size modulo 2^32, so the
 --list option reports incorrect uncompressed sizes and compression
@@ -483,7 +504,8 @@ the default compression level (-6). On some highly redundant files,
 compresses better than
 .IR gzip .
 .SH "COPYRIGHT NOTICE"
-Copyright \(co 1998, 1999, 2001, 2002, 2012 Free Software Foundation, Inc.
+Copyright \(co 1998-1999, 2001-2002, 2012, 2015-2016 Free Software Foundation,
+Inc.
 .br
 Copyright \(co 1992, 1993 Jean-loup Gailly
 .PP