diff --git a/mathicsscript/__main__.py b/mathicsscript/__main__.py
index 1ba232a..c408cc4 100755
--- a/mathicsscript/__main__.py
+++ b/mathicsscript/__main__.py
@@ -1,6 +1,17 @@
 #!/usr/bin/env python3
 #   Copyright (C) 2025 Rocky Bernstein <rb@dustyfeet.com>
-# -*- coding: utf-8 -*-
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
 import os.path as osp
diff --git a/mathicsscript/completion.py b/mathicsscript/completion.py
index eb9d439..91d0f4f 100644
--- a/mathicsscript/completion.py
+++ b/mathicsscript/completion.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 
-# Copyright (C) 2021-2022, 2024 Rocky Bernstein <rb@dustyfeet.com>
+# Copyright (C) 2021-2022, 2024-2025 Rocky Bernstein <rb@dustyfeet.com>
 #   This program is free software: you can redistribute it and/or modify
 #   it under the terms of the GNU General Public License as published by
 #   the Free Software Foundation, either version 3 of the License, or
@@ -67,6 +67,7 @@ class InterruptCompleter(Completer):
     COMMANDS = [
         "abort",
         "continue",
+        "debugger",
         "exit",
         "inspect",
         "show",
diff --git a/mathicsscript/interrupt.py b/mathicsscript/interrupt.py
index 7193564..2ca38dc 100644
--- a/mathicsscript/interrupt.py
+++ b/mathicsscript/interrupt.py
@@ -1,3 +1,16 @@
+# Copyright (C) 2025 Rocky Bernstein <rb@dustyfeet.com>
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 mathicsscript Interrupt routines.
 
@@ -108,6 +121,8 @@ def Mathics3_interrupt_handler(
             elif user_input in ("continue", "c"):
                 print_fn("continuing")
                 break
+            elif user_input in ("debugger", "d"):
+                breakpoint()
             elif user_input in ("exit", "quit"):
                 print_fn("Mathics3 exited because of an interrupt.")
                 sys.exit(3)
@@ -138,6 +153,7 @@ def Mathics3_interrupt_handler(
                     """Your options are:
 	abort (or a) to abort current calculation
 	continue (or c) to continue
+	debugger (or d) to to enter a Python debugger
 	exit (or quit) to exit Mathics3
 	inspect (or i) to enter an interactive dialog
 	show (or s) to show current operation (and then continue)
diff --git a/mathicsscript/termshell_gnu.py b/mathicsscript/termshell_gnu.py
index 8eb9511..ee5e378 100644
--- a/mathicsscript/termshell_gnu.py
+++ b/mathicsscript/termshell_gnu.py
@@ -120,7 +120,7 @@ def complete_interrupt_command(self, text, state):
         # Only complete from this fixed set
         completions = [
             w
-            for w in ["abort", "continue", "exit", "inspect", "show"]
+            for w in ["abort", "continue", "debugger", "exit", "inspect", "show"]
             if w.startswith(text)
         ]
         try: