title: Command-line variable assignments in Cygwin Bash not working?
body: <p>According to section 3.7.1 of the Bash manual, variable assignments at the beginning of a command line should be visible to the invoked program.</p>
  
  <p>e.g.</p>
  
  <pre><code>DIR=/tmp ls $DIR
  </code></pre>
  
  <p>should behave as if I've typed "ls /tmp" - and the variable DIR should not persist after executing the command.</p>
  
  <p>Cygwin Bash (GNU bash, version 3.2.51(24)-release (i686-pc-cygwin)) appears not to do this - the above command behaves as if $DIR is not defined.  This is confirmed by other tests such as "DIR=/tmp echo $DIR", "DIR=/tmp set" etc.</p>
  
  <p>Note that adding a semicolon works ("DIR=/tmp ; ls $DIR"), but leaves the variable defined after the command.</p>
  
  <p>Why is this not working as expected?</p>