Description
bool 
file_exists ( string filename )
     Returns TRUE if the file or directory specified by
     filename exists; FALSE otherwise.
    
     On windows, use //computername/share/filename or
     \\computername\share\filename to check files on
     network shares.
    
     
Example 1. Testing whether a file exists 
<?php $filename = '/path/to/foo.txt';
  if (file_exists($filename)) {     echo "The file $filename exists"; } else {     echo "The file $filename does not exist"; } ?>
 |  
  | 
    Note: The results of this 
function are cached. See clearstatcache() for 
more details.
Tip: As of PHP 5.0.0 this function
can also be used with some URL wrappers.  Refer to 
Appendix M for a listing of which wrappers support 
stat() family of functionality.
     See also is_readable(), is_writable(),
     is_file() and file().