Re: stat: clarify mtime vs ctime [patch]

[Assaf Gordon]

On 04/21/2014 03:57 PM, Pádraig Brady wrote:
> On 04/21/2014 08:14 PM, Assaf Gordon wrote:
> > Would you be receptive to adding a tiny patch to 'stat' to clarify the 
> > difference between modification time and change time?
> This clarification is worth making, thanks!
>
> > Perhaps, in addition, add a new FAQ ?
>
> Let's avoid the FAQ for the moment.
> Hopefully the improved docs will avoid the need.

<...>

> but
> if the file was just opened for reading, then access time isn't updated,
> only if data is read. Also for performance reasons, modern Linux systems
> only update atime if it's older than [cm]time.
> I.E. with relatime enabled, it's really only an indicator
> as to whether the file has been read since it was last updated.
> So I think this whole block might add more ambiguity than
> any additional clarification. OK to drop this block?

Attached are improved patches:
The first contains only the added words "status" and "data".

The second adds the paragraph to the docs, and can be included at your 
discretion.
I've reworded the "Access Time" sentence to make clear it depends on the 
operating system and file system configuration.
But I think at least the "data modification time" and "status change time" 
sentences are correct for all systems.

For both the FAQ and the additional paragraph, my reasoning is:
1. Expert users (who know by heart what mtime vs ctime mean) - don't need any 
of these.
2. Seasoned users - perhaps just need a reminder, in which case the words "data" vs 
"status" are enough.
3. Other (most?) users - will still look for clarification after seeing "data modification 
time" vs "status change time".

There are many answers for "what is the difference between modification time and change 
time" found on the internet, but I think it would be beneficial if there's an authoritative 
answer, from a reliable source (i.e. by "coreutils").

Regards,
 -gordon

0001-doc-clarify-stat-s-mtime-vs-ctime-in-usage-doc.patch
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0002-doc-add-paragraph-about-stat-s-x-y-z.patch
Description: Text Data