title: Issue with unix: merging two lines with sed
body: <p>I have a strange problem that can't get to fix. I am using the following bash script to merge two lines together on unix. However, the last column of the first line gets combined (with no space) with the first column of the second line. Can someone help please?</p>
  
  <pre><code>sed 'N;s/\n/  /' input.txt &gt;&gt; output.txt
  </code></pre>
  
  <p>input:</p>
  
  <pre><code>chr6    108930289   108930461   GWNJ-0842:521:GW1906282259th:8:1101:11373:39475:GCCAAGsize=1
  HPV45   5328    5400    GWNJ-0842:521:GW1906282259th:8:1101:11373:39475:GCCAAGsize=1
  chr3    153084969   153085002   GWNJ-0842:521:GW1906282259th:8:1101:14560:33322:GCCAATsize=6
  HPV45   4014    4219    GWNJ-0842:521:GW1906282259th:8:1101:14560:33322:GCCAATsize=6
  </code></pre>
  
  <p>output: (HPV45 for example is attached to 1 before it)</p>
  
  <pre><code>chr6    108930289   108930461   GWNJ-0842:521:GW1906282259th:8:1101:11373:39475:GCCAAGsize=1HPV45   5328    5400    GWNJ-0842:521:GW1906282259th:8:1101:11373:39475:GCCAAGsize=1
  chr3    153084969   153085002   GWNJ-0842:521:GW1906282259th:8:1101:14560:33322:GCCAATsize=6HPV45   4014    4219    GWNJ-0842:521:GW1906282259th:8:1101:14560:33322:GCCAATsize=6
  </code></pre>