title: List files starting with a specific character
body: <p>I have a folder which contains files of the following names <code>"5_45name.Rdata"</code>and <code>"15_45name.Rdata"</code>.</p>
  
  <p>I would like to list only the ones starting with "5", in the example above this means that I would like to exclude <code>"15_45name.Rdata"</code>.</p>
  
  <p>Using <code>list.files(pattern="5_*name.Rdata")</code>, however, will list both of these files.</p>
  
  <p>Is there a way to tell list.files() that I want the filename to start with a specific character?</p>