title: Where is the syntax `while IFS= read line` documented?
body: <p>Why does every example I see have <code>while IFS= read line</code> and not <code>while IFS=; read line</code>? </p>
  
  <p>I thought that <code>name=value command</code> might set a local variable but <code>sentence="hello" echo $sentence</code>doesn't work, while <code>sentence="hello"; echo $sentence</code> does.</p>