Use term width to determine header length

IPython/core/ultratb.py

@@ -124,6 +124,7 b' from IPython.utils import path as util_path'
 from IPython.utils import py3compat
 from IPython.utils import ulinecache
 from IPython.utils.data import uniq_stable
+from IPython.utils.terminal import get_terminal_size
 from logging import info, error
 
 import IPython.utils.colorable as colorable
@@ -1029,20 +1030,21 b' class VerboseTB(TBTools):'
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         exc = '%s%s%s' % (colors.excName, etype, colorsnormal)
+        width = min(75, get_terminal_size()[0])
         if long_version:
             # Header with the exception type, python version, and date
             pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
             date = time.ctime(time.time())
 
-            head = '%s%s%s\n%s%s%s\n%s' % (colors.topline, '-' * 75, colorsnormal,
-                                           exc, ' ' * (75 - len(str(etype)) - len(pyver)),
-                                           pyver, date.rjust(75) )
+            head = '%s%s%s\n%s%s%s\n%s' % (colors.topline, '-' * width, colorsnormal,
+                                           exc, ' ' * (width - len(str(etype)) - len(pyver)),
+                                           pyver, date.rjust(width) )
             head += "\nA problem occurred executing Python code.  Here is the sequence of function" \
                     "\ncalls leading up to the error, with the most recent (innermost) call last."
         else:
             # Simplified header
             head = '%s%s' % (exc, 'Traceback (most recent call last)'. \
-                             rjust(75 - len(str(etype))) )
+                             rjust(width - len(str(etype))) )
 
         return head
 
@@ -1155,7 +1157,7 b' class VerboseTB(TBTools):'
 
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
-        head = '%s%s%s' % (colors.topline, '-' * 75, colorsnormal)
+        head = '%s%s%s' % (colors.topline, '-' * min(75, get_terminal_size()[0]), colorsnormal)
         structured_traceback_parts = [head]
         if py3compat.PY3:
             chained_exceptions_tb_offset = 0

IPython/utils/terminal.py

@@ -24,6 +24,7 b' import os'
 import struct
 import sys
 import warnings
+import backports.shutil_get_terminal_size
 
 from . import py3compat
 
@@ -120,37 +121,5 b' def freeze_term_title():'
     ignore_termtitle = True
 
 
-if sys.platform == 'win32':
     def get_terminal_size(defaultx=80, defaulty=25):
-        """Return size of current terminal console.
-
-        This function try to determine actual size of current working
-        console window and return tuple (sizex, sizey) if success,
-        or default size (defaultx, defaulty) otherwise.
-
-        Dependencies: ctypes should be installed.
-
-        Author: Alexander Belchenko (e-mail: bialix AT ukr.net)
-        """
-        try:
-            import ctypes
-        except ImportError:
-            return defaultx, defaulty
-
-        h = ctypes.windll.kernel32.GetStdHandle(-11)
-        csbi = ctypes.create_string_buffer(22)
-        res = ctypes.windll.kernel32.GetConsoleScreenBufferInfo(h, csbi)
-
-        if res:
-            (bufx, bufy, curx, cury, wattr,
-             left, top, right, bottom, maxx, maxy) = struct.unpack(
-                "hhhhHhhhhhh", csbi.raw)
-            sizex = right - left + 1
-            sizey = bottom - top + 1
-            return (sizex, sizey)
-        else:
-            return (defaultx, defaulty)
-else:
-    def get_terminal_size(defaultx=80, defaulty=25):
-        return defaultx, defaulty
-
+    return backports.shutil_get_terminal_size.get_terminal_size((defaultx, defaulty))

setup.py

@@ -197,6 +197,7 b' install_requires = ['
     'traitlets',
     'prompt_toolkit>=0.58',
     'pygments',
+    'backports.shutil_get_terminal_size',
 ]
 
 # Platform-specific dependencies: