diff --git a/lib/dtutils/file.lua b/lib/dtutils/file.lua
index a6e2404..9f02bfd 100644
--- a/lib/dtutils/file.lua
+++ b/lib/dtutils/file.lua
@@ -773,61 +773,5 @@ function dtutils_file.rmdir(path)
   return dsys.external_command(rm_cmd.." "..path)
 end
 
-function dtutils_file.is_dir(path)
-  local cmd = nil
-
-  if dt.configuration.running_os == "windows" then
-    cmd = "if exist " .. ds.sanitize(path .. "\\*")
-  else
-    cmd = "test -d " .. ds.sanitize(path)
-  end
-
-  return os.execute(cmd)
-end
-
-function dtutils_file.is_file(path)
-  local cmd = nil
-
-  if dt.configuration.running_os == "windows" then
-    if not dtutils_file.is_dir(path) then
-      cmd = "if exist " .. ds.sanitize(path)
-    else
-      return nil
-    end
-  else
-    cmd = "test -f " .. ds.sanitize(path)
-  end
-
-  return os.execute(cmd)
-end
-
-local function is_windows_executable(path)
-  local result = nil
-
-  if (string.match(path, ".exe$") or string.match(path, ".EXE$")) or
-     (string.match(path, ".com$") or string.match(path, ".COM$")) or
-     (string.match(path, ".bat$") or string.match(path, ".BAT$")) or
-     (string.match(path, ".cmd$") or string.match(path, ".CMD$")) then
-      result = true
-  end
-  return result
-end
-
-
-function dtutils_file.is_executable(path)
-
-  local result = nil
-
-  if dt.configuration.running_os == "windows" then
-    if _is_windows_executable(path) then
-        result = true
-    end
-  else
-    result = os.execute("test -x " .. ds.sanitize(path))
-  end
-  return result
-end
-
-
 return dtutils_file