title: Nextflow multiple inputs with different number of files
body: <p>I'm trying to input two channels. However, the seacr_res_ch2 has 4 files, bigwig_ch3 has 5 files which contain a control and 4 samples. So I was trying to run the following process to compute the peak center.
  When I ran this process I have got this error:  unexpected EOF while looking for matching `&quot;'</p>
  <pre><code>process compute_matrix_peak_center {
  
      input:
      set val(sample_id), file(seacr_bed) from seacr_res_ch2
      set val(sample_id), file(bigwig) from bigwig_ch3
  
      output:
      set val(sample_id), file(&quot;${sample_id}.peak_centered.mat.gz&quot;) into peak_center_ch
  
      script:
      &quot;&quot;&quot;
  
      &quot;computeMatrix reference-point \
          -S ${bigwig} \
          -R ${seacr_bed} \
          -a 1000 \
          -b 1000 \
          -o ${sample_id}.peak_centered.mat.gz \
          --referencePoint center \
          -p 10
  
      &quot;&quot;&quot;
  }
  </code></pre>