Re: /dev/one - why not /dev/repeat?

Riley Williams (rhw@bigfoot.com)
Sun, 27 Dec 1998 06:33:52 +0000 (GMT)


Hi Dave.

>> That does exactly what my previous C-based example did, and uses
>> nothing that isn't part of bash itself. As a result, assuming that
>> bash is present, it will work...

> dd if=/dev/zero of=/tmp/shit bs=102400 count=10

> Please try to duplicate the use of '/dev/zero' with your function:

What for? That's not what you asked for previously...

> spam '0' | dd of=/tmp/shit bs=102400 count=10????

> Nope.

> mkfifo /tmp/tmpshit
> spam '0' >tmpshit &
> dd if=/tmp/tmpshit of=/tmp/shit bs=102400 count=10???

> No try again. And yes I know '0' != 0 but try to get a null bit
> past the shell. Best of luck. echo only knows char bytes.

So? '\0' is a char byte, and a SMALL tweak to the source thereof will
allow it to be included. Since you're apparently so fond of presenting
challenges, I'm sure that will take you no longer than 10 seconds to
work out, so will challenge you to fix it...

> I do wish you people would actually TRY your examples before using
> them as a basis for argument.

I do wish YOU would actually present CONSISTANT arguments, or can I
point out that you originally stated your request as being to provide
a means of producing a VARIABLE string, not one consisting of only
NULL bytes...and, as yourself stated in your earlier message, that
particular value is perfectly served by /dev/zero anyway...

Incidentally, that snippet was not only tested, but is actually in use
(at least, the function in it is) in the database script I wrote. The
code was extracted from said script, nothing was changed, and only the
final line was added, since that's specific to your ORIGINAL request
(and, of course, the ability to send any of the \x sequences was
specifically EXCLUDED from the database script, hence allowing your
fraudulant complaint when you so drastically changed the specs)...

> If you do figure out a way to get it semi-working, please use
> 'time' on it. You will find what I already know...echo is EXTREMLY
> slow.

> time with /dev/zero:
> real 0m0.021s
> user 0m0.010s
> sys 0m0.010s

That argument is a non-starter - ANYTHING written entirely as bash
script is EXTREMELY slow compared to the same thing written as C code.
Since you've already excluded the use of C code, you just shot
yourself in the foot...

Unless, of course, you'd forgotten that over 90% of what's in the
kernel is C code, and the rest is assembler, neither of which is any
form of shell script...and as YOU are asking that MANY people be
inconvenienced by YOUR request for C CODE to be added to the kernel so
you can FRAUDULANTLY claim that some shell script you write is faster
than some other shell script should be...words fail me...

Now, for reference, I will state that any further posts from you that
fail to present a REASONED argument that is CONSISTANT with your
previous posts will be filed in /dev/null without reply...

Best wishes from Riley.

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