diff --git Lib/argparse.py Lib/argparse.py
index f0cfe27..71c3a4c 100644
--- Lib/argparse.py
+++ Lib/argparse.py
@@ -89,6 +89,9 @@ import os as _os
 import re as _re
 import sys as _sys
 import textwrap as _textwrap
+import fcntl as _fcntl
+import termios as _termios
+import struct as _struct
 
 from gettext import gettext as _, ngettext
 
@@ -140,11 +143,24 @@ def _ensure_value(namespace, name, value):
         setattr(namespace, name, value)
     return getattr(namespace, name)
 
-
 # ===============
 # Formatting Help
 # ===============
 
+def _terminal_width(default=80):
+    try:
+        # An environment variable has higher priority
+        width = int(_os.environ['COLUMNS'])
+    except (KeyError, ValueError):
+        format = _struct.pack('HHHH', 0, 0, 0, 0)
+        try:
+            output = _fcntl.ioctl(1, _termios.TIOCGWINSZ, format)
+            width = _struct.unpack('HHHH', output)[1]
+        except IOError:
+            # If nothing worked, let's follow the time-honored tradition
+            width = default
+    return width
+
 class HelpFormatter(object):
     """Formatter for generating usage messages and argument help strings.
 
@@ -160,11 +176,7 @@ class HelpFormatter(object):
 
         # default setting for width
         if width is None:
-            try:
-                width = int(_os.environ['COLUMNS'])
-            except (KeyError, ValueError):
-                width = 80
-            width -= 2
+            width = _terminal_width() - 2
 
         self._prog = prog
         self._indent_increment = indent_increment