** Changes in behavior
- When acting in-place, gzip now fsyncs the output before closing it.
- This is slower, but on many file systems it is safer if the system
- is about to crash.
-
The GZIP environment variable is now obsolescent; gzip now warns if
it is used, and rejects attempts to use dangerous options or operands.
You can use an alias or script instead.
+ Installed programs like 'zgrep' now use the PATH environment variable
+ as usual to find subsidiary programs like 'gzip' and 'grep'.
+ Previously they prepended the installation directory to the PATH,
+ which sometimes caused 'make check' to test the wrong gzip executable.
+ [bug introduced in gzip-1.3.13]
+
+** New features
+
+ gzip now accepts the --synchronous option, which causes it to use
+ fsync and similar primitives to transfer output data to the output
+ file's storage device when the file system supports this. Although
+ this option makes gzip safer in the presence of system crashes, it
+ can make gzip considerably slower.
+
+ gzip now accepts the --rsyncable option. This option is accepted in
+ all modes, but has effect only when compressing: it makes the resulting
+ output more amenable to efficient use of rsync. For example, when a
+ large input file gets a small change, a gzip --rsyncable image of
+ that file will remain largely unchanged, too. Without --rsyncable,
+ even a tiny change in the input could result in a totally different
+ gzip-compressed output file.
+
** Bug fixes
gzip -k -v no longer reports that files are replaced.