'rm' Can not delete files

[Daniel Staal]

--As of February 10, 2012 4:24:58 PM +0000, Matthew Seaman is alleged to 
have said:

> On 10/02/2012 16:04, Matthew Story wrote:
>> find . -type f -depth 1 -print0 | xargs -n99 -0 -s8192 -c5 rm --
>>
>> or some such, depending on your needs, I believe in most situations this
>> particular invocation will also out-perform find ... -delete.
>
> Why would you believe that? find ... -delete calls unlink(2) directly on
> each file it finds as it searches the directory tree given that it
> matches the other find predicates.
>
> Whereas find ... -print0 | xargs ... rm ... involves a whole complicated
> sequence of find doing the same searching and matching job, then
> marshalling lists of filenames, piping them between processes, then
> xargs exec(2)ing rm with chunks of that arglist; each rm invocation then
> finally ... calling unlink(2) on each of the named files.

On the other hand, passing it through xargs makes the deletion 
multi-threaded (well, multi-process), while using -delete keeps it all in 
one process.  Depending on your execution environment, that may be a win.

> Actually, I doubt you'ld see much difference above the noise in the
> speed of either of those two commands: they're both going to spend the
> vast majority of the time waiting for disk IO, and that's common to any
> way of doing this job.

This is likely the root of the issue however.  ;)   (There are probably 
some pathological cases of multi-processor, multi-controller, multi-disk 
systems where having multiple IO streams would make a difference, but they 
are likely to be few for something like this.)

Daniel T. Staal

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