Re: [coreutils] Re: [PATCH 2/2] stat: print timestamps to full resolution

[Jim Meyering]

Jim Meyering wrote:

> Eric Blake wrote:
>
>> On 10/21/2010 08:09 AM, Andreas Schwab wrote:
>>> Eric Blake<address@hidden>  writes:
>>>
>>>> On 10/21/2010 03:22 AM, Andreas Schwab wrote:
>>>>>
>>>>>
>>>>> Jim Meyering<address@hidden>   writes:
>>>>>
>>>>>> And besides, with coreutils-8.6 already released, reverting the
>>>>>> change is no longer an option.
>>>>>
>>>>> Why?  I'm pretty sure more breakage will pop up over time.
>>>>
>>>> How would you propose 'fixing' it?
>>>
>>> Add a flag character, eg. %.X.
>>
>> %.X is no good, since we already support %.1X (that is, all printf()
>> flags should keep their existing printf() meaning). But Jim's proposal
>> of %:X for extended stat info, especially given how date already
>> supports %:z for extended timezone formatting, makes sense to me.  In
>> fact, %.3:X might be a nice way to request that the result be
>> displayed in milliseconds, although Jim's proof of concept patch
>> didn't cover that aspect.
>
> An alternative would be to leave %X, %Y, etc. as the only
> operators that print seconds-since-epoch, and let the new %:X
> print the nanoseconds part of the associated time.
>
> Then, to get full seconds.nanoseconds, you'd use a format like %X.%:X
> and if you want only milliseconds, you'd use %X.%3.3:X

Oops.
I forgot to zero-pad.  Otherwise, with < 100,000,000ns in the first
case or < 100 in the 2nd, and the above would print invalid numbers.

This is the right way:

  To get full seconds.nanoseconds, you'd use a format like %X.%0:X
  and if you want only milliseconds, you'd use %X.%03.3:X