perl -MData::Dump=pp 
-wle"opendir D,'.';m[\.([^.]+$)]&&++$exts{$1}while$_=readdir D;pp\%exts"

{
  "0_01" => 1,
  1      => 2,
  2      => 1,
  3      => 1,
  4      => 1,
  au3    => 1,
  bak    => 2,
  "bak'" => 1,
  bin    => 2,
  bmp    => 1,
  c      => 15,
  csv    => 2,
  dat    => 14,
  dat1   => 1,
  dat2   => 1,
  dis    => 1,
  dll    => 3,
  emf    => 1,
  evt    => 1,
  exe    => 9,
  "exp"  => 1,
  file   => 1,
  flv    => 1,
  h      => 2,
  htm    => 1,
  jpg    => 10,
  js     => 1,
  lib    => 1,
  obj    => 8,
  out    => 1,
  pl     => 207,
  pm     => 8,
  png    => 13,
  sortex => 1,
  swf    => 1,
  tar    => 1,
  tws    => 1,
  txt    => 13,
  xls    => 1,
  xml    => 1,
  zip    => 3,
}