On 2017年09月25日 22:19, Hugo Mills wrote:
On Mon, Sep 25, 2017 at 04:04:03PM +0800, Qu Wenruo wrote:
On 2017年09月25日 15:52, Hugo Mills wrote:
On Mon, Sep 25, 2017 at 03:46:15PM +0800, Qu Wenruo wrote:
On 2017年09月25日 15:42, Marat Khalili wrote:
On 25/09/17 10:30, Nikolay Borisov wrote:
On 19.09.2017 10:41, Misono, Tomohiro wrote:
"btrfs subvolume create/delete" outputs the message of "Create/Delete
subvolume ..." even when an operation fails.
Since it is confusing, let's outputs the message only when an
operation succeeds.
Please change the verb to past tense, more strongly signaling success -
i.e. "Created subvolume"
What about recalling some UNIX standards and returning to NOT
outputting any message when operation succeeds? My scripts are
full of grep -v calls after each btrfs command, and this sucks
(and I don't think I'm alone in this situation).
Isn't the correct way to catch the return value instead of grepping
the output?
It is, but if, for example, you're using the command in a cron
script which is expected to work, you don't want it producing output
because then you get a mail every time the script runs. So you have to
grep -v on the "success" output to make the successful script silent.
What about redirecting stdout to /dev/null and redirecting stderr to
mail if return value is not 0?
As for expected-to-work case, the stdout doesn't has much meaning
and return value should be good enough to judge the result.
If it's some command not returning value properly, would you please
report it as a bug so we can fix it.
It's not the return value that's problematic (although those used
to be a real mess). It's the fact that a successful run of the command
produces noise on stdout, which most commands don't.
Yes, a lot of tried-and-true tools don't output anything for
successful run, but also a lot of other tools do output something by
default, especially for complex tools like LVM.
btrfs sub create and btrfs sub delete, though, aren't complex.
They're about as complex as mkdir and rmdir, from a user point of
view. What's more, and like mkdir/rmdir, the effects of those commands
show up in the filesystem at the path given, so manual verification
could be as simple as "ls -d !$" or "ls !$/..". It's really, really
not necessary to have this command unconditionally print "yes, I
created a directory for you" to stdout.
Yes, there's ways to deal with it in shell scripts, but wouldn't
life be so much better if you didn't have to? Like you don't have to
filter out success reports from mkdir.
Maybe we can introduce a global --quite option to silent some output.
Or drop the spurious output unless it's asked for with --verbose.
Because then it makes it so much easier to compose tools together into
bigger and more complex things, which is, after all, one of the
fundamental things that UNIX does right.
I think we need at least 4 levels of message: debug, info, warn, error.
And only show debug and higher for --verbose.
Default to show info, and warn/error always get show (stderr).
(And during the new framework, we can add support for translation)
And we also need to reassign all existing message to new message level.
It may be time consuming but we just need to do it since there is real
user demand here.
(Any in this case, anyone in the maillist can help review messages)
Thanks,
Qu
Hugo.
Thanks,
Qu
Hugo.
Thanks,
Qu
If you change the message a lot of scripts will have to be
changed, at least make it worth it.
--
With Best Regards,
Marat Khaliili
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
