> What is the default value for --compress-level=? 6? 9?
> The fine manual only mentions:
> Explicitly set the compression level to use (see
> --compress) instead of letting it default. If NUM is
> non-zero, the --compress option is implied.
> Also, what are allowed values? 1-9? 0-9? Something else?
From a comment in zlib/zlib.h in the source:
The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
1 gives best speed, 9 gives best compression, 0 gives no compression at
all (the input data is simply copied a block at a time).
Z_DEFAULT_COMPRESSION requests a default compromise between speed and
compression (currently equivalent to level 6).
Z_DEFAULT_COMPRESSION is defined as (-1), and appears to be the value
used if --compress is specified without --compress-level, making the
default functionally equivalent to 6.