title: Nested for loop in Bash using structure
body: <p>I'm running a nested for loop in bash using structure for a class. I've written the script and it works but I'm confused about why the character (which is bolded), K in this case, is necessary in the curly brackets after structure -K when I've already stated that I want K 1-5?
  This is what I have-</p>
  
  <pre><code>for K in {1..5}
  do
      for run in {1..3}
      do
          echo "K = ${K}; run = ${run}"
          structure -K **${K}** -o K_${K}_run_${run}.txt
      done
  done
  </code></pre>