use strict;
use warnings;

sub re_name
{
  my $path = $_[0];

  #append a trailing / if it's not there
  if($path !~ /\/$/)
  {
    $path .= '/';
  }

  #loop through the files contained in the directory
  for my $eachFile (glob($path.'*'))
  {

    #if the file is a directory
    if(-d $eachFile)
    {
      #pass the directory to the routine ( recursion )
      re_name($eachFile);
    }
    else
    {
     my @strings = split('/', $eachFile);
     my $fileName = $strings[$#strings];
     my $filePath = '/'.join('/', @strings[2..$#strings-1]);
     system("mv $filePath/$fileName $filePath/newfile");
    }
  }
}
re_name('.');
re_name('/tmp/654653');