new file mode 100644
--- /dev/null
+++ b/lib/file-type.c
@@ -0,0 +1,43 @@
+char const *
+file_type (struct stat const *st)
+{
+  /* See POSIX 1003.1-2001 for these formats.
+
+     To keep diagnostics grammatical in English, the returned string
+     must start with a consonant.  */
+
+  if (S_ISREG (st->st_mode))
+    return st->st_size == 0 ? _("regular empty file") : _("regular file");
+
+  if (S_ISDIR (st->st_mode))
+    return _("directory");
+
+  if (S_ISBLK (st->st_mode))
+    return _("block special file");
+
+  if (S_ISCHR (st->st_mode))
+    return _("character special file");
+
+  if (S_ISFIFO (st->st_mode))
+    return _("fifo");
+
+  if (S_ISLNK (st->st_mode))
+    return _("symbolic link");
+
+  if (S_ISSOCK (st->st_mode))
+    return _("socket");
+
+  if (S_TYPEISMQ (st))
+    return _("message queue");
+
+  if (S_TYPEISSEM (st))
+    return _("semaphore");
+
+  if (S_TYPEISSHM (st))
+    return _("shared memory object");
+
+  if (S_TYPEISTMO (st))
+    return _("typed memory object");
+
+  return _("weird file");
+}