[Toybox] [PATCH] Clarify fallocate help text.

[Rob Landley]

On 09/30/2016 05:05 PM, enh wrote:
> -l isn't optional, and fallocate accepts the same suffixes as truncate.
> 
> (As do many other commands. We might prefer to just *not* document
> this anyway and have to teach people that toybox [mostly] accepts
> the same set of suffixes everywhere. dd is a place where the suffixes
> differ, but the fix there might also be to make atollx support the
> whole dd set.)

Yeah, part of my cleanup todo list is working out what to do there. The
problem is I've done 2/3 of that cleanup three times now, gotten
interrupted each time, and lost track of where I was. Trying to check it
in in smaller chunks this time around, but it's... kinda tangled together.

> I did watch someone work out 3221225472 so they could supply it as an
> argument to fallocate, though.

Sigh. The shell does $((32<<20)) for you. (Oddly enough, << 10 is a
kilobyte, <<20 a megabyte, <<30 a gigabyte, <<40 a terabyte, <<50 a
petabyte...)

I poked the busybox guys about consistently doing 64 bit math on 32 bit
platforms ages ago, ala
http://lists.busybox.net/pipermail/busybox/2009-January/068143.html and
I think I posted here more recently about the "truncate -s 8g" problem
on 32 bit hosts (argument parsing logic uses longs).

> A half-way solution might be to always
> have terminology like "-l New length (accepts usual suffixes)", rather
> than explicitly write them out? (We're already not documenting that
> 2K==2k, and if we do in future accept the full dd set everywhere,
> that's two lines of help in a lot of commands.)

Hmmm. Saying "prefixed number" makes sense but saying 'suffixed number"
seems kinda awkward. Possibly I'm undercaffeinated.

I've tried hard to make toybox's behavior _consistent_, which in theory
means I shouldn't to be repetitive in the help text. (I don't usually
point out "-" means stdin or "--" terminates option parsing, for
example.). Truncate documents them because the truncate man page
documented them, but they're the same sufixes for any standard command
line numerical input. (grep -A accepts the suffixes, nice -n accepts
them... the results aren't meaningful and the range clipping would
object, but it'll parse them first in the common codepath.)

Because of that I was tempted to move the explanation to "toybox
--help", but I don't expect most people would see it, and you've pointed
out people don't see it as a unified whole...

Really it would be nice if there was a way to indicate in the usage:
line that this is a numerical input. Unfortunately the syntax I'm
copying from various man pages doesn't seem to have anything like an
official definition.

> Bug: 31638516

Is there a way for me to look at these bug reports?

Rob