title: How to mkdir only if a directory does not already exist?
body: <p>I am writing a shell script to run under the KornShell (ksh) on AIX. I would like to use the <code>mkdir</code> command to create a directory. But the directory may already exist, in which case I do not want to do anything. So I want to either test to see that the directory does not exist, or suppress the "File exists" error that <code>mkdir</code> throws when it tries to create an existing directory. </p>
  
  <p>How can I best do this?</p>