-The command @arv keep get@ fetches the contents of the locator @c1bad4b39ca5a924e481008009d94e32+210@. This is a locator for a collection data block, so it fetches the contents of the collection. In this example, this collection consists of a single file @var-GS000016015-ASM.tsv.bz2@ which is 227212247 bytes long, and is stored using four sequential data blocks, <code>204e43b8a1185621ca55a94839582e6f+67108864</code>, <code>b9677abbac956bd3e86b1deb28dfac03+67108864</code>, <code>fc15aff2a762b13f521baf042140acec+67108864</code>, <code>323d2a3ce20370c4ca1d3462a344f8fd+25885655</code>.
+The command @arv keep get@ fetches the contents of the collection @c1bad4b39ca5a924e481008009d94e32+210@. In this example, this collection includes a single file @var-GS000016015-ASM.tsv.bz2@ which is 227212247 bytes long, and is stored using four sequential data blocks, @204e43b8a1185621ca55a94839582e6f+67108864@, @b9677abbac956bd3e86b1deb28dfac03+67108864@, @fc15aff2a762b13f521baf042140acec+67108864@, and @323d2a3ce20370c4ca1d3462a344f8fd+25885655@.
+
+Let's use @arv keep get@ to download the first data block:
+
+notextile. <pre><code>~$ <span class="userinput">cd /scratch/<b>you</b></span>
+/scratch/<b>you</b>$ <span class="userinput">arv keep get 204e43b8a1185621ca55a94839582e6f+67108864 > block1</span></code></pre>
+
+{% include 'notebox_begin' %}
+
+When you run this command, you may get this API warning:
+
+notextile. <pre><code>WARNING:root:API lookup failed for collection 204e43b8a1185621ca55a94839582e6f+67108864 (<class 'apiclient.errors.HttpError'>: <HttpError 404 when requesting https://qr1hi.arvadosapi.com/arvados/v1/collections/204e43b8a1185621ca55a94839582e6f%2B67108864?alt=json returned "Not Found">)</code></pre>