Re: [PATCH v4 1/5] t9300: factor out portable "head -c" replacement

From

Junio C Hamano <gitster@pobox.com>

Date

Jul 1, 2016, 17:23 UTC

Message-ID

<xmqqd1mxz30m.fsf@gitster.mtv.corp.google.com>

In-Reply-To

<20160630090753.GA17463@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

> In shell scripts it is sometimes useful to be able to read
> exactly N bytes from a pipe. Doing this portably turns out
> to be surprisingly difficult.

I'd rotate the above by three words ;-).

    It is sometimes useful to be able to read
    exactly N bytes from a pipe. Doing this portably turns out
    to be surprisingly difficult
    in shell scripts.

>   - "dd bs=1 count=$n" fixes the partial read problem (all
>     reads are 1-byte, so there can be no partial response).
>     It does make a lot of write() calls, but for our tests
>     that's unlikely to matter.

> That makes the perl solution the least bad (because we
> conveniently omitted "length of code" as a criterion).
> It's also what t9300 is currently using, so we can just pull
> the implementation from there.

;-).

The patch itself is good.