---
layout: default
navsection: userguide
+navmenu: Tutorials
title: "Parallel Crunch tasks"
-navorder: 115
+navorder: 15
---
h1. Tutorial: Parallel Crunch tasks
</code></pre>
</notextile>
-You should now be able to run your new script using Crunch, with "script" referring to our new "parallel-hash.py" script. We will use a different input from our previous examples. We will use @887cd41e9c613463eab2f0d885c6dd96+83@ which consists of three files, "alice.txt", "bob.txt" and "carol.txt" (the example collection used previously in "fetching data from Arvados using Keep":intro-keep.html).
+You should now be able to run your new script using Crunch, with "script" referring to our new "parallel-hash.py" script. We will use a different input from our previous examples. We will use @887cd41e9c613463eab2f0d885c6dd96+83@ which consists of three files, "alice.txt", "bob.txt" and "carol.txt" (the example collection used previously in "fetching data from Arvados using Keep":tutorial-keep.html).
<notextile>
<pre><code>$ <span class="userinput">cat >the_job <<EOF
$ <span class="userinput">arv -h job get --uuid qr1hi-xxxxx-xxxxxxxxxxxxxxx</span>
{
...
- "output":"e2ccd204bca37c77c0ba59fc470cd0f7+162+K@qr1hi",
+ "output":"e2ccd204bca37c77c0ba59fc470cd0f7+162",
...
}
</code></pre>
Because the job ran in parallel, each instance of parallel-hash creates a separate @md5sum.txt@ as output. Arvados automatically collates theses files into a single collection, which is the output of the job:
<notextile>
-<pre><code>$ <span class="userinput">arv keep get e2ccd204bca37c77c0ba59fc470cd0f7+162+K@qr1hi</span>
+<pre><code>$ <span class="userinput">arv keep get e2ccd204bca37c77c0ba59fc470cd0f7+162</span>
md5sum.txt
md5sum.txt
md5sum.txt
-$ <span class="userinput">arv keep get e2ccd204bca37c77c0ba59fc470cd0f7+162+K@qr1hi/md5sum.txt</span>
+$ <span class="userinput">arv keep get e2ccd204bca37c77c0ba59fc470cd0f7+162/md5sum.txt</span>
0f1d6bcf55c34bed7f92a805d2d89bbf alice.txt
504938460ef369cd275e4ef58994cffe bob.txt
8f3b36aff310e06f3c5b9e95678ff77a carol.txt