title: concatenate variable doesn't work how I want
body: <p>I need to concatenate two variables and a character</p>
  
  <p>The first variable <code>$line</code> is read from a file by <code>line=$(awk "NR==$i" in_parameters.txt)</code>.</p>
  
  <pre><code>echo $line
  2;0.250;0.250;1.520;0.000;0.025;32
  </code></pre>
  
  <p>The second variable is also read from a file</p>
  
  <pre><code>extr_out=$(awk "NR==1" "${i}_out.txt")
  
  echo $extr_out
  0.249510039979791
  </code></pre>
  
  <p>What I want is create <code>line2= $line + ";" + $extr_out</code></p>
  
  <pre><code>echo $line2
  2;0.250;0.250;1.520;0.000;0.025;32;0.249510039979791
  </code></pre>
  
  <p>I tried using</p>
  
  <pre><code>line2=$line
  line2+=";"
  echo $line2
  ;;0.250;0.250;1.520;0.000;0.025;32
  </code></pre>
  
  <p>or</p>
  
  <pre><code>line2=$line$extr_out
  echo $line2
  &amp;nbsp;&amp;nbsp;0.2495100399797910;0.000;0.025;32
  </code></pre>
  
  <p>but the problem is that the value is written at the beginning of the chain and not appended at the end.</p>
  
  <p>I probably do not understand something correctly. Can anybody help me with that? How does bash work with these variables?</p>