diff --git a/.gitignore b/.gitignore
index d6e0d3e60c..828fb04e7d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@
 .idea
 /etc/spackconfig
 /share/spack/dotkit
+/share/spack/modules
diff --git a/bin/spack b/bin/spack
index c63178b191..f2b5d1d583 100755
--- a/bin/spack
+++ b/bin/spack
@@ -75,6 +75,13 @@ for cmd in spack.cmd.commands:
     module = spack.cmd.get_module(cmd)
     subparser = subparsers.add_parser(cmd, help=module.description)
     module.setup_parser(subparser)
+
+# Just print help and exit if run with no arguments at all
+if len(sys.argv) == 1:
+    parser.print_help()
+    sys.exit(1)
+
+# actually parse the args.
 args = parser.parse_args()
 
 # Set up environment based on args.
diff --git a/lib/spack/spack/__init__.py b/lib/spack/spack/__init__.py
index 9eae4342e3..ab8978cecf 100644
--- a/lib/spack/spack/__init__.py
+++ b/lib/spack/spack/__init__.py
@@ -58,7 +58,6 @@
 stage_path     = join_path(var_path, "stage")
 install_path   = join_path(prefix, "opt")
 share_path     = join_path(prefix, "share", "spack")
-dotkit_path    = join_path(share_path, "dotkit")
 
 #
 # Set up the packages database.
diff --git a/lib/spack/spack/cmd/dotkit.py b/lib/spack/spack/cmd/dotkit.py
deleted file mode 100644
index 7a691ae5c0..0000000000
--- a/lib/spack/spack/cmd/dotkit.py
+++ /dev/null
@@ -1,99 +0,0 @@
-##############################################################################
-# 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
-##############################################################################
-import sys
-import os
-import shutil
-import argparse
-
-import llnl.util.tty as tty
-from llnl.util.lang import partition_list
-from llnl.util.filesystem import mkdirp
-
-import spack.cmd
-import spack.hooks.dotkit
-from spack.spec import Spec
-
-
-description ="Find dotkits for packages if they exist."
-
-def setup_parser(subparser):
-    subparser.add_argument(
-        '--refresh', action='store_true', help='Regenerate all dotkits')
-
-    subparser.add_argument(
-        'spec', nargs=argparse.REMAINDER, help='spec to find a dotkit for.')
-
-
-def dotkit_find(parser, args):
-    if not args.spec:
-        parser.parse_args(['dotkit', '-h'])
-
-    spec = spack.cmd.parse_specs(args.spec)
-    if len(spec) > 1:
-        tty.die("You can only pass one spec.")
-    spec = spec[0]
-
-    if not spack.db.exists(spec.name):
-        tty.die("No such package: %s" % spec.name)
-
-    specs = [s for s in spack.db.installed_package_specs() if s.satisfies(spec)]
-
-    if len(specs) == 0:
-        tty.die("No installed packages match spec %s" % spec)
-
-    if len(specs) > 1:
-        tty.error("Multiple matches for spec %s.  Choose one:" % spec)
-        for s in specs:
-            sys.stderr.write(s.tree(color=True))
-        sys.exit(1)
-
-    match = specs[0]
-    if not os.path.isfile(spack.hooks.dotkit.dotkit_file(match.package)):
-        tty.die("No dotkit is installed for package %s." % spec)
-
-    print match.format('$_$@$+$%@$=$#')
-
-
-def dotkit_refresh(parser, args):
-    query_specs = spack.cmd.parse_specs(args.spec)
-
-    specs = spack.db.installed_package_specs()
-    if query_specs:
-        specs = [s for s in specs
-                 if any(s.satisfies(q) for q in query_specs)]
-    else:
-        shutil.rmtree(spack.dotkit_path, ignore_errors=False)
-        mkdirp(spack.dotkit_path)
-
-    for spec in specs:
-        spack.hooks.dotkit.post_install(spec.package)
-
-
-
-def dotkit(parser, args):
-    if args.refresh:
-        dotkit_refresh(parser, args)
-    else:
-        dotkit_find(parser, args)
diff --git a/lib/spack/spack/cmd/load.py b/lib/spack/spack/cmd/load.py
new file mode 100644
index 0000000000..5bc6b15784
--- /dev/null
+++ b/lib/spack/spack/cmd/load.py
@@ -0,0 +1,38 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by David Beckingsale, david@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
+##############################################################################
+import argparse
+import spack.modules
+
+description ="Add package to environment using modules."
+
+def setup_parser(subparser):
+    """Parser is only constructed so that this prints a nice help
+       message with -h. """
+    subparser.add_argument(
+        'spec', nargs=argparse.REMAINDER, help='Spec of package to load with modules.')
+
+
+def load(parser, args):
+    spack.modules.print_help()
diff --git a/lib/spack/spack/cmd/module.py b/lib/spack/spack/cmd/module.py
new file mode 100644
index 0000000000..4f6de18532
--- /dev/null
+++ b/lib/spack/spack/cmd/module.py
@@ -0,0 +1,108 @@
+##############################################################################
+# 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
+##############################################################################
+import sys
+import os
+import shutil
+import argparse
+
+import llnl.util.tty as tty
+from llnl.util.lang import partition_list
+from llnl.util.filesystem import mkdirp
+
+import spack.cmd
+from spack.modules import module_types
+from spack.util.string import *
+
+from spack.spec import Spec
+
+description ="Manipulate modules and dotkits."
+
+
+def setup_parser(subparser):
+    sp = subparser.add_subparsers(metavar='SUBCOMMAND', dest='module_command')
+
+    refresh_parser = sp.add_parser('refresh', help='Regenerate all module files.')
+
+    find_parser = sp.add_parser('find', help='Find module files for packages.')
+    find_parser.add_argument(
+        'module_type', help="Type of module to find file for. [" + '|'.join(module_types) + "]")
+    find_parser.add_argument('spec', nargs='+', help='spec to find a module file for.')
+
+
+def module_find(mtype, spec_array):
+    """Look at all installed packages and see if the spec provided
+       matches any.  If it does, check whether there is a module file
+       of type <mtype> there, and print out the name that the user
+       should type to use that package's module.
+    """
+    specs = spack.cmd.parse_specs(spec_array)
+    if len(specs) > 1:
+        tty.die("You can only pass one spec.")
+    spec = specs[0]
+
+    if mtype not in module_types:
+        tty.die("Invalid module type: '%s'.  Options are " + comma_and(module_types))
+
+    specs = [s for s in spack.db.installed_package_specs() if s.satisfies(spec)]
+    if len(specs) == 0:
+        tty.die("No installed packages match spec %s" % spec)
+
+    if len(specs) > 1:
+        tty.error("Multiple matches for spec %s.  Choose one:" % spec)
+        for s in specs:
+            sys.stderr.write(s.tree(color=True))
+        sys.exit(1)
+
+    mt = module_types[mtype]
+    mod = mt(specs[0].package)
+    if not os.path.isfile(mod.file_name):
+        tty.error( mod.file_name)
+        tty.die("No %s module is installed for package %s." % (mtype, spec))
+
+    print mod.use_name
+
+
+def module_refresh():
+    """Regenerate all module files for installed packages known to
+       spack (some packages may no longer exist)."""
+    specs = [s for s in spack.db.installed_known_package_specs()]
+
+    for name, cls in module_types.items():
+        tty.msg("Regenerating %s module files." % name)
+        if os.path.isdir(cls.path):
+            shutil.rmtree(cls.path, ignore_errors=False)
+        mkdirp(cls.path)
+        for spec in specs:
+            tty.debug("   Writing file for %s." % spec)
+            cls(spec.package).write()
+
+
+
+def module(parser, args):
+    if args.module_command == 'refresh':
+        module_refresh()
+
+    elif args.module_command == 'find':
+        module_find(args.module_type, args.spec)
diff --git a/lib/spack/spack/cmd/unload.py b/lib/spack/spack/cmd/unload.py
new file mode 100644
index 0000000000..24e49b3f24
--- /dev/null
+++ b/lib/spack/spack/cmd/unload.py
@@ -0,0 +1,38 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by David Beckingsale, david@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
+##############################################################################
+import argparse
+import spack.modules
+
+description ="Remove package from environment using module."
+
+def setup_parser(subparser):
+    """Parser is only constructed so that this prints a nice help
+       message with -h. """
+    subparser.add_argument(
+        'spec', nargs=argparse.REMAINDER, help='Spec of package to unload with modules.')
+
+
+def unload(parser, args):
+    spack.modules.print_help()
diff --git a/lib/spack/spack/cmd/unuse.py b/lib/spack/spack/cmd/unuse.py
index a31e16d11a..7f0b384ea0 100644
--- a/lib/spack/spack/cmd/unuse.py
+++ b/lib/spack/spack/cmd/unuse.py
@@ -23,14 +23,16 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import argparse
-import spack.cmd.use
+import spack.modules
 
 description ="Remove package from environment using dotkit."
 
 def setup_parser(subparser):
+    """Parser is only constructed so that this prints a nice help
+       message with -h. """
     subparser.add_argument(
-        'spec', nargs=argparse.REMAINDER, help='Spec of package to remove.')
+        'spec', nargs=argparse.REMAINDER, help='Spec of package to unuse with dotkit.')
 
 
 def unuse(parser, args):
-    spack.cmd.use.print_help()
+    spack.modules.print_help()
diff --git a/lib/spack/spack/cmd/use.py b/lib/spack/spack/cmd/use.py
index 10a0644df8..4990fea2f8 100644
--- a/lib/spack/spack/cmd/use.py
+++ b/lib/spack/spack/cmd/use.py
@@ -23,28 +23,16 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import argparse
-import llnl.util.tty as tty
-import spack
+import spack.modules
 
 description ="Add package to environment using dotkit."
 
 def setup_parser(subparser):
+    """Parser is only constructed so that this prints a nice help
+       message with -h. """
     subparser.add_argument(
-        'spec', nargs=argparse.REMAINDER, help='Spec of package to add.')
-
-
-def print_help():
-    tty.msg("Spack dotkit support is not initialized.",
-            "",
-            "To use dotkit with Spack, you must first run the command",
-            "below, which you can copy and paste:",
-            "",
-            "For bash:",
-            "    . %s/setup-env.bash" % spack.share_path,
-            "",
-            "ksh/csh/tcsh shells are currently unsupported",
-            "")
+        'spec', nargs=argparse.REMAINDER, help='Spec of package to use with dotkit.')
 
 
 def use(parser, args):
-    print_help()
+    spack.modules.print_help()
diff --git a/lib/spack/spack/hooks/dotkit.py b/lib/spack/spack/hooks/dotkit.py
index 10b7732353..0f46f6a2fc 100644
--- a/lib/spack/spack/hooks/dotkit.py
+++ b/lib/spack/spack/hooks/dotkit.py
@@ -22,62 +22,14 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import os
-import re
-import textwrap
-import shutil
-from contextlib import closing
-
-from llnl.util.filesystem import join_path, mkdirp
-
-import spack
-
-
-def dotkit_file(pkg):
-    dk_file_name = pkg.spec.format('$_$@$%@$+$=$#') + ".dk"
-    return join_path(spack.dotkit_path, dk_file_name)
+import spack.modules
 
 
 def post_install(pkg):
-    if not os.path.exists(spack.dotkit_path):
-        mkdirp(spack.dotkit_path)
-
-    alterations = []
-    for var, path in [
-        ('PATH', pkg.prefix.bin),
-        ('MANPATH', pkg.prefix.man),
-        ('MANPATH', pkg.prefix.share_man),
-        ('LD_LIBRARY_PATH', pkg.prefix.lib),
-        ('LD_LIBRARY_PATH', pkg.prefix.lib64)]:
-
-        if os.path.isdir(path):
-            alterations.append("dk_alter %s %s\n" % (var, path))
-
-    if not alterations:
-        return
-
-    alterations.append("dk_alter CMAKE_PREFIX_PATH %s\n" % pkg.prefix)
-
-    dk_file = dotkit_file(pkg)
-    with closing(open(dk_file, 'w')) as dk:
-        # Put everything in the spack category.
-        dk.write('#c spack\n')
-
-        dk.write('#d %s\n' % pkg.spec.format("$_ $@"))
-
-        # Recycle the description
-        if pkg.__doc__:
-            doc = re.sub(r'\s+', ' ', pkg.__doc__)
-            for line in textwrap.wrap(doc, 72):
-                dk.write("#h %s\n" % line)
-
-        # Write alterations
-        for alter in alterations:
-            dk.write(alter)
+    dk = spack.modules.Dotkit(pkg)
+    dk.write()
 
 
 def post_uninstall(pkg):
-    dk_file = dotkit_file(pkg)
-    if os.path.exists(dk_file):
-        shutil.rmtree(dk_file, ignore_errors=True)
-
+    dk = spack.modules.Dotkit(pkg)
+    dk.remove()
diff --git a/lib/spack/spack/hooks/tclmodule.py b/lib/spack/spack/hooks/tclmodule.py
new file mode 100644
index 0000000000..d93da3177e
--- /dev/null
+++ b/lib/spack/spack/hooks/tclmodule.py
@@ -0,0 +1,35 @@
+##############################################################################
+# Copyright (c) 2013, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by David Beckingsale, david@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
+##############################################################################
+import spack.modules
+
+
+def post_install(pkg):
+    dk = spack.modules.TclModule(pkg)
+    dk.write()
+
+
+def post_uninstall(pkg):
+    dk = spack.modules.TclModule(pkg)
+    dk.remove()
diff --git a/lib/spack/spack/modules.py b/lib/spack/spack/modules.py
new file mode 100644
index 0000000000..3f56208f5b
--- /dev/null
+++ b/lib/spack/spack/modules.py
@@ -0,0 +1,247 @@
+##############################################################################
+# 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
+##############################################################################
+"""This module contains code for creating environment modules, which
+can include dotkits, tcl modules, lmod, and others.
+
+The various types of modules are installed by post-install hooks and
+removed after an uninstall by post-uninstall hooks.  This class
+consolidates the logic for creating an abstract description of the
+information that module systems need.  Currently that includes a
+number directories to be appended to paths in the user's environment:
+
+  * /bin directories to be appended to PATH
+  * /lib* directories for LD_LIBRARY_PATH
+  * /man* and /share/man* directories for LD_LIBRARY_PATH
+  * the package prefix for CMAKE_PREFIX_PATH
+
+This module also includes logic for coming up with unique names for
+the module files so that they can be found by the various
+shell-support files in $SPACK/share/spack/setup-env.*.
+
+Each hook in hooks/ implements the logic for writing its specific type
+of module file.
+"""
+__all__ = ['EnvModule', 'Dotkit', 'TclModule']
+
+import os
+import re
+import textwrap
+import shutil
+from contextlib import closing
+
+import llnl.util.tty as tty
+from llnl.util.filesystem import join_path, mkdirp
+
+import spack
+
+"""Registry of all types of modules.  Entries created by EnvModule's
+   metaclass."""
+module_types = {}
+
+
+def print_help():
+    """For use by commands to tell user how to activate shell support."""
+
+    tty.msg("Spack module/dotkit support is not initialized.",
+            "",
+            "To use dotkit or modules with Spack, you must first run",
+            "one of the commands below.  You can copy/paste them.",
+            "",
+            "For bash and zsh:",
+            "    . %s/setup-env.sh" % spack.share_path,
+            "",
+            "For csh and tcsh:",
+            "    setenv SPACK_ROOT %s"    % spack.prefix,
+            "    source %s/setup-env.csh" % spack.share_path,
+            "")
+
+
+class EnvModule(object):
+    name = 'env_module'
+
+    class __metaclass__(type):
+        def __init__(cls, name, bases, dict):
+            type.__init__(cls, name, bases, dict)
+            if cls.name != 'env_module':
+                module_types[cls.name] = cls
+
+
+    def __init__(self, pkg=None):
+        # category in the modules system
+        # TODO: come up with smarter category names.
+        self.category = "spack"
+
+        # Descriptions for the module system's UI
+        self.short_description = ""
+        self.long_description = ""
+
+        # dict pathname -> list of directories to be prepended to in
+        # the module file.
+        self._paths = None
+        self.pkg = pkg
+
+
+    @property
+    def paths(self):
+        if self._paths is None:
+            self._paths = {}
+
+            def add_path(path_name, directory):
+                path = self._paths.setdefault(path_name, [])
+                path.append(directory)
+
+            # Add paths if they exist.
+            for var, directory in [
+                    ('PATH', self.pkg.prefix.bin),
+                    ('MANPATH', self.pkg.prefix.man),
+                    ('MANPATH', self.pkg.prefix.share_man),
+                    ('LD_LIBRARY_PATH', self.pkg.prefix.lib),
+                    ('LD_LIBRARY_PATH', self.pkg.prefix.lib64)]:
+
+                if os.path.isdir(directory):
+                    add_path(var, directory)
+
+            # short description is just the package + version
+            # TODO: maybe packages can optionally provide it.
+            self.short_description = self.pkg.spec.format("$_ $@")
+
+            # long description is the docstring with reduced whitespace.
+            if self.pkg.__doc__:
+                self.long_description = re.sub(r'\s+', ' ', self.pkg.__doc__)
+
+        return self._paths
+
+
+    def write(self):
+        """Write out a module file for this object."""
+        module_dir = os.path.dirname(self.file_name)
+        if not os.path.exists(module_dir):
+            mkdirp(module_dir)
+
+        # If there are no paths, no need for a dotkit.
+        if not self.paths:
+            return
+
+        with closing(open(self.file_name, 'w')) as f:
+            self._write(f)
+
+
+    def _write(self, stream):
+        """To be implemented by subclasses."""
+        raise NotImplementedError()
+
+
+    @property
+    def file_name(self):
+        """Subclasses should implement this to return the name of the file
+           where this module lives."""
+        raise NotImplementedError()
+
+
+    @property
+    def use_name(self):
+        """Subclasses should implement this to return the name the
+           module command uses to refer to the package."""
+        raise NotImplementedError()
+
+
+    def remove(self):
+        mod_file = self.file_name
+        if os.path.exists(mod_file):
+            shutil.rmtree(mod_file, ignore_errors=True)
+
+
+class Dotkit(EnvModule):
+    name = 'dotkit'
+    path = join_path(spack.share_path, "dotkit")
+
+    @property
+    def file_name(self):
+        return join_path(Dotkit.path, self.pkg.spec.architecture,
+                         self.pkg.spec.format('$_$@$%@$+$#.dk'))
+
+    @property
+    def use_name(self):
+        return self.pkg.spec.format('$_$@$%@$+$#')
+
+
+    def _write(self, dk_file):
+        # Category
+        if self.category:
+            dk_file.write('#c %s\n' % self.category)
+
+        # Short description
+        if self.short_description:
+            dk_file.write('#d %s\n' % self.short_description)
+
+        # Long description
+        if self.long_description:
+            for line in textwrap.wrap(self.long_description, 72):
+                dk_file.write("#h %s\n" % line)
+
+        # Path alterations
+        for var, dirs in self.paths.items():
+            for directory in dirs:
+                dk_file.write("dk_alter %s %s\n" % (var, directory))
+
+        # Let CMake find this package.
+        dk_file.write("dk_alter CMAKE_PREFIX_PATH %s\n" % self.pkg.prefix)
+
+
+class TclModule(EnvModule):
+    name = 'tcl'
+    path = join_path(spack.share_path, "modules")
+
+    @property
+    def file_name(self):
+        return join_path(TclModule.path, self.pkg.spec.architecture, self.use_name)
+
+
+    @property
+    def use_name(self):
+        return self.pkg.spec.format('$_$@$%@$+$#')
+
+
+    def _write(self, m_file):
+        # TODO: cateogry?
+        m_file.write('#%Module1.0\n')
+
+        # Short description
+        if self.short_description:
+            m_file.write('module-whatis \"%s\"\n\n' % self.short_description)
+
+        # Long description
+        if self.long_description:
+            m_file.write('proc ModulesHelp { } {\n')
+            doc = re.sub(r'"', '\"', self.long_description)
+            m_file.write("puts stderr \"%s\"\n" % doc)
+            m_file.write('}\n\n')
+
+        # Path alterations
+        for var, dirs in self.paths.items():
+            for directory in dirs:
+                m_file.write("prepend-path %s \"%s\"\n" % (var, directory))
+
+        m_file.write("prepend-path CMAKE_PREFIX_PATH \"%s\"\n" % self.pkg.prefix)
diff --git a/lib/spack/spack/packages.py b/lib/spack/spack/packages.py
index ba997bf269..fd75d8e326 100644
--- a/lib/spack/spack/packages.py
+++ b/lib/spack/spack/packages.py
@@ -124,6 +124,16 @@ def installed_package_specs(self):
         return installed
 
 
+    def installed_known_package_specs(self):
+        """Read installed package names straight from the install
+           directory layout, but return only specs for which the
+           package is known to this version of spack.
+        """
+        for spec in spack.install_layout.all_specs():
+            if self.exists(spec.name):
+                yield spec
+
+
     @memoized
     def all_package_names(self):
         """Generator function for all packages.  This looks for
diff --git a/share/spack/csh/spack.csh b/share/spack/csh/spack.csh
new file mode 100644
index 0000000000..169e9878bf
--- /dev/null
+++ b/share/spack/csh/spack.csh
@@ -0,0 +1,91 @@
+########################################################################
+# This is a wrapper around the spack command that forwards calls to
+# 'spack use' and 'spack unuse' to shell functions.  This in turn
+# allows them to be used to invoke dotkit functions.
+#
+# 'spack use' is smarter than just 'use' because it converts its
+# arguments into a unique spack spec that is then passed to dotkit
+# commands.  This allows the user to use packages without knowing all
+# their installation details.
+#
+# e.g., rather than requring a full spec for libelf, the user can type:
+#
+#     spack use libelf
+#
+# This will first find the available libelf dotkits and use a
+# matching one.  If there are two versions of libelf, the user would
+# need to be more specific, e.g.:
+#
+#     spack use libelf@0.8.13
+#
+# This is very similar to how regular spack commands work and it
+# avoids the need to come up with a user-friendly naming scheme for
+# spack dotfiles.
+########################################################################
+# accumulate initial flags for main spack command
+set _sp_flags = ""
+while ( $#_sp_args > 0 )
+    if ( "$_sp_args[1]" !~ "-*" ) break
+    set _sp_flags = "$_sp_flags $_sp_args[1]"
+    shift _sp_args
+end
+
+# h and V flags don't require further output parsing.
+if ( "$_sp_flags" =~ *h* || "$_sp_flags" =~ *V* ) then
+    \spack $_sp_flags $_sp_args
+    goto _sp_end
+endif
+
+# Set up args -- we want a subcommand and a spec.
+set _sp_subcommand=""
+set _sp_spec=""
+[ $#_sp_args -gt 0 ] && set _sp_subcommand = ($_sp_args[1])
+[ $#_sp_args -gt 1 ] && set _sp_spec = ($_sp_args[2-])
+
+# Figure out what type of module we're running here.
+set _sp_modtype = ""
+switch ($_sp_subcommand)
+case use:
+case unuse:
+case load:
+case unload:
+    set _sp_module_args=""""
+    if ( "$_sp_spec" =~ "-*" ) then
+        set _sp_module_args = $_sp_spec[1]
+        shift _sp_spec
+        set _sp_spec = ($_sp_spec)
+    endif
+    # Translate the parameter into pieces of a command.
+    # _sp_modtype is an arg to spack module find, and
+    # _sp_sh_cmd is the equivalent shell command.
+    switch ($_sp_subcommand)
+        case use:
+        case unuse:
+            set _sp_modtype = dotkit
+            set _sp_sh_cmd = ( "`alias $_sp_subcommand'" )
+            breaksw
+        case load:
+        case unload:
+            set _sp_modtype = tcl
+            set _sp_sh_cmd = ( "`alias module`" $_sp_subcommand )
+            breaksw
+    endsw
+
+    # Here the user has run use or unuse with a spec.  Find a matching
+    # spec using 'spack module find', then use the appropriate module
+    # tool's commands to add/remove the result from the environment.
+    # If spack module command comes back with an error, do nothing.
+    set _sp_full_spec = ""
+    if { set _sp_full_spec = `\spack module find $_sp_modtype $_sp_spec` } then
+         $_sp_sh_cmd $_sp_module_args $_sp_full_spec
+    endif
+    breaksw
+
+default:
+    \spack $_sp_args
+    breaksw
+endsw
+
+_sp_end:
+unset _sp_args _sp_full_spec _sp_modtype _sp_module_args
+unset _sp_sh_cmd _sp_spec _sp_subcommand _sp_flags
diff --git a/share/spack/csh/spack_pathadd.csh b/share/spack/csh/spack_pathadd.csh
new file mode 100644
index 0000000000..1e0800c5f3
--- /dev/null
+++ b/share/spack/csh/spack_pathadd.csh
@@ -0,0 +1,23 @@
+########################################################################
+# Prepends directories to path, if they exist.
+#      pathadd /path/to/dir            # add to PATH
+# or   pathadd OTHERPATH /path/to/dir  # add to OTHERPATH
+########################################################################
+# If no variable name is supplied, just append to PATH
+# otherwise append to that variable.
+set _pa_varname = PATH;
+set _pa_new_path = $_pa_args[1];
+[ $#_pa_args -gt 1 ] && set _pa_varname = $_pa_args[1] && set _pa_new_path = $_pa_args[2];
+
+# Check whether the variable is set yet.
+set _pa_old_value = ""
+eval set _pa_set = '$?'$_pa_varname
+[ $_pa_set -eq 1 ] && eval set _pa_old_value='$'$_pa_varname;
+
+# Do the actual prepending here, if it is a dir and not already in the path
+if ( -d $_pa_new_path && \:$_pa_old_value\: !~ *\:$_pa_new_path\:* ) then
+    [ -n "$_pa_old_value" ] && setenv $_pa_varname $_pa_new_path\:$_pa_old_value
+    [ -z "$_pa_old_value" ] && setenv $_pa_varname $_pa_new_path
+endif
+
+unset _pa_args _pa_new_path _pa_old_value _pa_set _pa_varname
diff --git a/share/spack/setup-env.bash b/share/spack/setup-env.bash
deleted file mode 100755
index e22a259167..0000000000
--- a/share/spack/setup-env.bash
+++ /dev/null
@@ -1,132 +0,0 @@
-##############################################################################
-# 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
-##############################################################################
-
-#
-#
-# This file is part of Spack and sets up the spack environment for
-# bash shells.  This includes dotkit support as well as putting spack
-# in your path.  Source it like this:
-#
-#    . /path/to/spack/share/spack/setup-env.bash
-#
-#
-
-
-########################################################################
-# This is a wrapper around the spack command that forwards calls to
-# 'spack use' and 'spack unuse' to shell functions.  This in turn
-# allows them to be used to invoke dotkit functions.
-#
-# 'spack use' is smarter than just 'use' because it converts its
-# arguments into a unique spack spec that is then passed to dotkit
-# commands.  This allows the user to use packages without knowing all
-# their installation details.
-#
-# e.g., rather than requring a full spec for libelf, the user can type:
-#
-#     spack use libelf
-#
-# This will first find the available libelf dotkits and use a
-# matching one.  If there are two versions of libelf, the user would
-# need to be more specific, e.g.:
-#
-#     spack use libelf@0.8.13
-#
-# This is very similar to how regular spack commands work and it
-# avoids the need to come up with a user-friendly naming scheme for
-# spack dotfiles.
-########################################################################
-function spack {
-    _spack_subcommand=$1; shift
-    _spack_spec="$@"
-
-    # Filter out use and unuse.  For any other commands, just run the
-    # command.
-    case $_spack_subcommand in
-        "use") ;;
-        "unuse") ;;
-        *)
-            command spack $_spack_subcommand "$@"
-            return
-            ;;
-    esac
-
-    # If no args or -h, just run that command as well.
-    if [ -z "$1" -o "$1" = "-h" ]; then
-        command spack $_spack_subcommand -h
-        return
-    fi
-
-    # Shift any other args for use off before parsing spec.
-    _spack_use_args=""
-    if [[ "$1" =~ ^- ]]; then
-        _spack_use_args="$1"; shift
-        _spack_spec="$@"
-    fi
-
-    # Here the user has run use or unuse with a spec.  Find a matching
-    # spec with a dotkit using spack dotkit, then use or unuse the
-    # result.  If spack dotkit comes back with an error, do nothing.
-    if _spack_full_spec=$(command spack dotkit $_spack_spec); then
-        $_spack_subcommand $_spack_use_args $_spack_full_spec
-    fi
-}
-
-########################################################################
-# Prepends directories to path, if they exist.
-#      pathadd /path/to/dir            # add to PATH
-# or   pathadd OTHERPATH /path/to/dir  # add to OTHERPATH
-########################################################################
-function _spack_pathadd {
-    # If no variable name is supplied, just append to PATH
-    # otherwise append to that variable.
-    varname=PATH
-    path="$1"
-    if [ -n "$2" ]; then
-        varname="$1"
-        path="$2"
-    fi
-
-    # Do the actual prepending here.
-    eval "oldvalue=\"\$$varname\""
-    if [ -d "$path" ] && [[ ":$oldvalue:" != *":$path:"* ]]; then
-        if [ -n "$oldvalue" ]; then
-            eval "export $varname=\"$path:$oldvalue\""
-        else
-            export $varname="$path"
-        fi
-    fi
-}
-
-
-#
-# Set up dotkit and path in the user environment
-#
-_spack_share_dir="$(dirname ${BASH_SOURCE[0]})"
-_spack_prefix="$(dirname $(dirname $_spack_share_dir))"
-
-_spack_pathadd DK_NODE "$_spack_share_dir/dotkit"
-_spack_pathadd PATH    "$_spack_prefix/bin"
-
diff --git a/share/spack/setup-env.csh b/share/spack/setup-env.csh
new file mode 100755
index 0000000000..cc12eae82f
--- /dev/null
+++ b/share/spack/setup-env.csh
@@ -0,0 +1,47 @@
+##############################################################################
+# 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
+##############################################################################
+
+#
+# This file is part of Spack and sets up the spack environment for
+# csh and tcsh.  This includes dotkit support, module support, and
+# it also puts spack in your path.  Source it like this:
+#
+#    setenv SPACK_ROOT /path/to/spack
+#    source $SPACK_ROOT/share/spack/setup-env.csh
+#
+if ($?SPACK_ROOT) then
+    set _spack_source_file = $SPACK_ROOT/share/spack/setup-env.csh
+    set _spack_share_dir   = $SPACK_ROOT/share/spack
+
+    # Command aliases point at separate source files
+    alias spack          'set _sp_args = (\!*); source $_spack_share_dir/csh/spack.csh'
+    alias _spack_pathadd 'set _pa_args = (\!*) && source $_spack_share_dir/csh/spack_pathadd.csh'
+
+    # Set up modules and dotkit search paths in the user environment
+    # TODO: fix SYS_TYPE to something non-LLNL-specific
+    _spack_pathadd DK_NODE    "$_spack_share_dir/dotkit/$SYS_TYPE"
+    _spack_pathadd MODULEPATH "$_spack_share_dir/modules/$SYS_TYPE"
+    _spack_pathadd PATH       "$SPACK_ROOT/bin"
+endif
diff --git a/share/spack/setup-env.sh b/share/spack/setup-env.sh
new file mode 100755
index 0000000000..0142e04817
--- /dev/null
+++ b/share/spack/setup-env.sh
@@ -0,0 +1,164 @@
+##############################################################################
+# 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
+##############################################################################
+
+#
+# This file is part of Spack and sets up the spack environment for
+# bash and zsh.  This includes dotkit support, module support, and
+# it also puts spack in your path.  Source it like this:
+#
+#    . /path/to/spack/share/spack/setup-env.sh
+#
+
+########################################################################
+# This is a wrapper around the spack command that forwards calls to
+# 'spack use' and 'spack unuse' to shell functions.  This in turn
+# allows them to be used to invoke dotkit functions.
+#
+# 'spack use' is smarter than just 'use' because it converts its
+# arguments into a unique spack spec that is then passed to dotkit
+# commands.  This allows the user to use packages without knowing all
+# their installation details.
+#
+# e.g., rather than requring a full spec for libelf, the user can type:
+#
+#     spack use libelf
+#
+# This will first find the available libelf dotkits and use a
+# matching one.  If there are two versions of libelf, the user would
+# need to be more specific, e.g.:
+#
+#     spack use libelf@0.8.13
+#
+# This is very similar to how regular spack commands work and it
+# avoids the need to come up with a user-friendly naming scheme for
+# spack dotfiles.
+########################################################################
+function spack {
+    # accumulate initial flags for main spack command
+    _sp_flags=""
+    while [[ "$1" =~ ^- ]]; do
+        _sp_flags="$_sp_flags $1"
+        shift
+    done
+
+    # h and V flags don't require further output parsing.
+    if [[ "$_sp_flags" =~ *h* || "$_sp_flags" =~ *V* ]]; then
+        command spack $_sp_flags "$@"
+        return
+    fi
+
+    _sp_subcommand=$1; shift
+    _sp_spec="$@"
+
+    # Filter out use and unuse.  For any other commands, just run the
+    # command.
+    case $_sp_subcommand in
+        "use"|"unuse"|"load"|"unload")
+            # Shift any other args for use off before parsing spec.
+            _sp_module_args=""
+            if [[ "$1" =~ ^- ]]; then
+                _sp_module_args="$1"; shift
+                _sp_spec="$@"
+            fi
+
+            # Translate the parameter into pieces of a command.
+            # _sp_modtype is an arg to spack module find, and
+            # _sp_sh_cmd is the equivalent shell command.
+            case $_sp_subcommand in
+                "use"|"unuse")
+                    _sp_modtype=dotkit
+                    _sp_sh_cmd=$_sp_subcommand
+                    ;;
+                "load"|"unload")
+                    _sp_modtype=tcl
+                    _sp_sh_cmd="module $_sp_subcommand"
+                    ;;
+            esac
+
+            # Here the user has run use or unuse with a spec.  Find a matching
+            # spec using 'spack module find', then use the appropriate module
+            # tool's commands to add/remove the result from the environment.
+            # If spack module command comes back with an error, do nothing.
+            if _sp_full_spec=$(command spack $_sp_flags module find $_sp_modtype $_sp_spec); then
+                $_sp_sh_cmd $_sp_module_args $_sp_full_spec
+            fi
+            return
+            ;;
+        *)
+            command spack $_sp_flags $_sp_subcommand $_sp_spec
+    esac
+}
+
+########################################################################
+# Prepends directories to path, if they exist.
+#      pathadd /path/to/dir            # add to PATH
+# or   pathadd OTHERPATH /path/to/dir  # add to OTHERPATH
+########################################################################
+function _spack_pathadd {
+    # If no variable name is supplied, just append to PATH
+    # otherwise append to that variable.
+    _pa_varname=PATH
+    _pa_new_path="$1"
+    if [ -n "$2" ]; then
+        _pa_varname="$1"
+        _pa_new_path="$2"
+    fi
+
+    # Do the actual prepending here.
+    eval "_pa_oldvalue=\$${_pa_varname}"
+
+    if [ -d "$_pa_new_path" ] && [[ ":$_pa_oldvalue:" != *":$_pa_new_path:"* ]]; then
+        if [ -n "$_pa_oldvalue" ]; then
+            eval "export $_pa_varname=\"$_pa_new_path:$_pa_oldvalue\""
+        else
+            export $_pa_varname="$_pa_new_path"
+        fi
+    fi
+}
+
+#
+# Figure out where this file is.  Below code needs to be portable to
+# bash and zsh.
+#
+_sp_source_file="${BASH_SOURCE[0]}"  # Bash's location of last sourced file.
+if [ -z "$_sp_source_file" ]; then
+    _sp_source_file="$0:A"           # zsh way to do it
+    if [[ "$_sp_source_file" == *":A" ]]; then
+        # Not zsh either... bail out with plain old $0,
+        # which WILL NOT work if this is sourced indirectly.
+        _sp_source_file="$0"
+    fi
+fi
+
+#
+# Set up modules and dotkit search paths in the user environment
+#
+_sp_share_dir="$(dirname $_sp_source_file)"
+_sp_prefix="$(dirname $(dirname $_sp_share_dir))"
+
+# TODO: fix SYS_TYPE to something non-LLNL-specific
+_spack_pathadd DK_NODE    "$_sp_share_dir/dotkit/$SYS_TYPE"
+_spack_pathadd MODULEPATH "$_sp_share_dir/modules/$SYS_TYPE"
+_spack_pathadd PATH       "$_sp_prefix/bin"