Chris's Wiki :: blog/unix/DdTwoFacets Commentshttps://utcc.utoronto.ca/~cks/space/blog/unix/DdTwoFacets?atomcommentsDWiki2023-03-23T23:22:33ZRecent comments in Chris's Wiki :: blog/unix/DdTwoFacets.By Verisimilitude on /blog/unix/DdTwoFacetstag:CSpace:blog/unix/DdTwoFacets:87a832afcd00e3312995ae8d6d8ac89ff5c63c79Verisimilitudehttp://verisimilitudes.net<div class="wikitext"><p>This confusion is a natural result of making no concrete decisions with regards to whether these programs should be used for results or effects.</p>
<blockquote><p>Also, at the time that system administrators started assuming that dd would perform their IO as 'written', I don't think anyone expected the degree of cleverness that modern Unix utilities and kernels exhibit</p>
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<p>Before GNU, did anyone expect them to work at all, without callously truncating lines deemed to be too long, alongside other atrocities?</p>
</div>2023-03-23T23:22:33ZFrom 193.219.181.219 on /blog/unix/DdTwoFacetstag:CSpace:blog/unix/DdTwoFacets:1131cb30aad3c8c210150be014eb8e5539062e42From 193.219.181.219<div class="wikitext"><blockquote><p>I use <code>sum FILENAME</code> to, e.g., read FILENAME from slow storage into the page cache for later use.</p>
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<p>My usual tool for that is <code>pv</code> (because of the progress bar), but I recently discovered <a href="https://github.com/hoytech/vmtouch"><code>vmtouch</code></a> for that purpose. It's not necessarily better, I just find it cool – e.g. its ability to show what parts of a file are <em>currently</em> in the page cache, as well as drop the specified files from cache.</p>
</div>2023-03-21T14:52:13ZBy Leah Neukirchen on /blog/unix/DdTwoFacetstag:CSpace:blog/unix/DdTwoFacets:2a76cc0f11dea7fe8d71b30ae641ca0b38217c0fLeah Neukirchenhttps://leahneukirchen.org/<div class="wikitext"><p>A POSIX-compliant dd must be implemented as a blockwise read-write loop.</p>
</div>2023-03-19T15:46:17ZBy Erik Auerswald on /blog/unix/DdTwoFacetstag:CSpace:blog/unix/DdTwoFacets:435298389cbbb1bc033d2e8fc61a0798d31b87c1Erik Auerswaldhttps://www.unix-ag.uni-kl.de/~auerswal/<div class="wikitext"><p>I use <code>sum FILENAME</code> to, e.g., read <code>FILENAME</code> from slow storage into the page cache for later use.</p>
<p>It is quite fast, because it uses a simple, old checksum algorithm by default, and it needs to read the data to compute the checksum.</p>
<p>I do <em>not</em> throw the output away to guard against <em>too clever</em> implementations.</p>
</div>2023-03-19T13:55:20Z