diff --git a/lib/spack/spack/cmd/activate.py b/lib/spack/spack/cmd/activate.py
new file mode 100644
index 0000000000000000000000000000000000000000..c1e23852d64c6f157e656dbd9b11303d2262c7df
--- /dev/null
+++ b/lib/spack/spack/cmd/activate.py
@@ -0,0 +1,50 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://scalability-llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# 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) version 2.1 dated February 1999.
+#
+# 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 terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from external import argparse
+import llnl.util.tty as tty
+import spack
+import spack.cmd
+
+description = "Activate a package extension."
+
+def setup_parser(subparser):
+    subparser.add_argument(
+        'spec', nargs=argparse.REMAINDER, help="spec of package extension to activate.")
+
+
+def activate(parser, args):
+    specs = spack.cmd.parse_specs(args.spec, concretize=True)
+    if len(specs) != 1:
+        tty.die("activate requires one spec.  %d given." % len(specs))
+
+    # TODO: remove this hack when DAG info is stored in dir layout.
+    # This ensures the ext spec is always normalized properly.
+    spack.db.get(specs[0])
+
+    spec = spack.cmd.disambiguate_spec(specs[0])
+    if spec.package.activated:
+        tty.die("Package %s is already activated." % specs[0].short_spec)
+
+    spec.package.do_activate()
diff --git a/lib/spack/spack/cmd/deactivate.py b/lib/spack/spack/cmd/deactivate.py
new file mode 100644
index 0000000000000000000000000000000000000000..fd13f051dfb098ebae4a6fab312dfff04c0c1641
--- /dev/null
+++ b/lib/spack/spack/cmd/deactivate.py
@@ -0,0 +1,50 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://scalability-llnl.github.io/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# 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) version 2.1 dated February 1999.
+#
+# 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 terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from external import argparse
+import llnl.util.tty as tty
+import spack
+import spack.cmd
+
+description = "Deactivate a package extension."
+
+def setup_parser(subparser):
+    subparser.add_argument(
+        'spec', nargs=argparse.REMAINDER, help="spec of package extension to deactivate.")
+
+
+def deactivate(parser, args):
+    specs = spack.cmd.parse_specs(args.spec, concretize=True)
+    if len(specs) != 1:
+        tty.die("deactivate requires one spec.  %d given." % len(specs))
+
+    # TODO: remove this hack when DAG info is stored in dir layout.
+    # This ensures the ext spec is always normalized properly.
+    spack.db.get(specs[0])
+
+    spec = spack.cmd.disambiguate_spec(specs[0])
+    if not spec.package.activated:
+        tty.die("Package %s is not activated." % specs[0].short_spec)
+
+    spec.package.do_deactivate()