did tar(1) loose xz compression support in 11?

Daniel Eischen deischen at freebsd.org
Wed Aug 27 17:28:52 UTC 2014

On Wed, 27 Aug 2014, Warren Block wrote:

> On Tue, 26 Aug 2014, Daniel Eischen wrote:
>> The man page is a little confusing.  Here it says:
>>  --options options
>>      Select optional behaviors for particular modules.  The
>>      argument is a text string containing comma-separated
>>      keywords and values. These are passed to the modules that
>>      handle particular formats to control how those formats will
>>      behave.  Each option has one of the following forms:
>>      key=value
>>              The key will be set to the specified value in every
>>              module that supports it.  Modules that do not
>>              support this key will ignore it.
>> Then below, after the last option, it says:
>>      ...
>>      zip:compression=type
>>              Use type as compression method.  Supported values are
>>              store (uncompressed) and deflate (gzip algorithm).
>>      If a provided option is not supported by any module, that is a
>>      fatal error.
>> The first states that it is ignored, the latter states that it
>> is a fatal error.  The meaning of "any module" is subtle, at
>> least for my feeble brain ;-)
> It suggests that options are passed to all modules, and each module is free 
> to ignore options it does not understand.  But at least one module must 
> understand the option, or a fatal error is reported.

Yes, I got that, but it is confusing when you are intentionally
passing to only one module, as in the original post, "xz:9",
and considering that the "fatal error" and "ignore it" parts
are listed in separate sections.  Regardless, tar(1) has many
options, so a little confusion is not unsurprising :-)


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