.I zip
can be uncompressed by gzip only if they have a single member compressed
with the 'deflation' method. This feature is only intended to help
-conversion of tar.zip files to the tar.gz format. To extract zip files
+conversion of tar.zip files to the tar.gz format. To extract a
+.I zip
+file with a single member, use a command like
+.I "gunzip <foo.zip"
+or
+.IR "gunzip -S .zip foo.zip" .
+To extract zip files
with several members, use
.I unzip
instead of
.I gzip
preserves the mode, ownership and timestamps of files when compressing
or decompressing.
+.PP
+The
+.I gzip
+file format is specified in P. Deutsch, \s-1GZIP\s0 file format
+specification version 4.3, <ftp://ftp.isi.edu/in-notes/rfc1952.txt>,
+Internet RFC 1952 (May 1996). The
+.I zip
+deflation format is specified in P. Deutsch, \s-1DEFLATE\s0 Compressed
+Data Format Specification version 1.3,
+<ftp://ftp.isi.edu/in-notes/rfc1951.txt>, Internet RFC 1951 (May 1996).
.SH OPTIONS
.TP
.I gunzip
).
.TP
+.B --rsyncable
+While compressing, synchronize the output occasionally based on the input.
+This increases size by less than 1 percent most cases, but means that the
+.BR rsync (1)
+program can much more efficiently synchronize files compressed with this flag.
+.I gunzip
+cannot tell the difference between a compressed file created with this option,
+and one created without it.
+.TP
.B \-S .suf --suffix .suf
Use suffix .suf instead of .gz. Any suffix can be given, but suffixes
other than .z and .gz should be avoided to avoid confusion when files
compresses better than
.I gzip.
.SH "COPYRIGHT NOTICE"
-Copyright \(co 1998, 1999, 2001 Free Software Foundation, Inc.
+Copyright \(co 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
.br
Copyright \(co 1992, 1993 Jean-loup Gailly
.PP