title: bash doesn't run commands in sequential order
body: <p>I have a bash script that contains the following:</p>
  
  <pre><code>MY_COMMAND="MY_PWD=`pwd`; export MY_PWD; MY_PWD_BASENAME=`basename $MY_PWD`; echo $MY_PWD_BASENAME"; export MY_COMMAND
  </code></pre>
  
  <p>When I source the script from the terminal, I get the following error:</p>
  
  <pre><code>basename: missing operand
  Try `basename --help' for more information.
  </code></pre>
  
  <p>This indicates that the commands in <code>MY_COMMAND</code> are not executed in sequential order.
  What is happening here?</p>