title: Regex to match dot character occuring alone in a line
body: <p>A sentence containing a single dot marks the end of the required portion of a file. It may or may not be the EOF. If I use flex and bison to parse this file, how can I match this line using some regular expression? Or is there some other way? I cannot use "." in Flex grammar as it can come anywhere in any portion, may be as  a part of some word, mail id, etc. </p>
  
  <p>Example: if my  input file is as shown:</p>
  
  <p>This is a simple file for testing.
  mail_id: abc@fgl.mn
  date: 20.09.2011
  here goes some lines of information.</p>
  
  <p>. </p>
  
  <p>[Here there can be more sentences].</p>
  
  <p>I need to parse only till that line containing that ".". How can I do that?</p>