title: jq --arg variable used in quoted string within select()
body: <p>I want to <code>select()</code> an object based on a string containing a jq variable (<code>$ARCH</code>) using <code>-arg</code> jq argument. Here's the use-case while looking for "<code>/bin/linux/$ARCH/kubeadm</code>" from Google...</p>
  
  <pre><code># You may need to install `xml2json` IE 
  # sudo gem install --no-rdoc --no-ri xml2json and run the script I wrote to do the xml2json:
  </code></pre>
  
  <hr>
  
  <pre><code>#!/usr/bin/ruby
  # Written by Jim Conner
  require 'xml2json'
  
  xml = ARGV[0]
  
  begin
    if xml == '-'
      xdata = ARGF.read.chomp
      puts XML2JSON.parse(xdata)
    else
      puts XML2JSON.parse(File.read(file2parse).chomp)
    end
  rescue =&gt; e
    $stderr.puts 'Unable to comply: %s' % [e.message]
  end
  </code></pre>
  
  <hr>
  
  <p>Then run the following:</p>
  
  <pre><code>curl -sSL https://storage.googleapis.com/kubernetes-release/ &gt; /var/tmp/k8s.xml | \
  xml2json - | \
  jq --arg ARCH amd64 '[.ListBucketResult.Contents[] | select(.Key | contains("/bin/linux/$arch/kubeadm"))]'
  </code></pre>
  
  <p>...which returns an empty set because <code>jq</code> doesn't transliterate inside quotes. I know I can get around this by using multiple select/contains() but I'd prefer not to if possible.</p>
  
  <p><code>jq</code> simply may not do it, but if someone knows a way to do it, I'd much appreciate it.</p>