From: Junio C Hamano Date: Fri, 24 Jun 2016 22:41:47 GMT Subject: Re: [PATCH v3 1/4] t5000: test tar files that overflow ustar headers Message-ID: In-Reply-To: <20160624205858.GA23315@sigill.intra.peff.net> Jeff King writes: > The difference in time between the two is measurable on my system, but > it's only a few milliseconds (for 4096 bytes). So maybe it's not worth > worrying about (though as a general technique, it does make me worry > that it's easy to get wrong in a way that will fail racily). Yeah, GNU dd has iflag=fullblock, but if we assume GNU, we can safely assume "head -c", so I do not think of a way to do this portably enough.