title: Detecting failure of a Bash "export" value
body: <p>In Bash I'm executing a command and putting the result in a variable like this:</p>
  
  <pre>export var=`svn ls`</pre>
  
  <p>But if SVN fails for some reason--say it returns a non-zero error code--export still returns status code 0. How do I detect if the executed command fails?</p>