title: Display month from number in bash script
body: <p>I'm trying to show that if you type something for the month it displays the month
  such as <code>january=1</code>, <code>february=2</code> , <code>march=3</code> ...</p>
  
  <p>and year <code>2012</code>,<code>2013</code>,<code>2014</code>...</p>
  
  <p>but if you type something greater than <code>12</code> for the month than it should tell you <code>"sorry"</code> and I can't figure out how to make the message work.</p>
  
  <pre><code>echo " please type a number for a month"
  read month
  echo " please type a number for a year"
  read year
  
  if [ "$month" = "1-12" ]
  then
          cal "$month" "$year"
          sleep 2
          echo " thank you, good bye... "
  else
          echo " sorry "  
          sleep 2
  fi
  </code></pre>