diff --git a/command.py b/command.py
new file mode 100644
index 0000000..516c2d9
--- /dev/null
+++ b/command.py
@@ -0,0 +1,116 @@
+#
+# Copyright (C) 2008 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import optparse
+import sys
+
+from error import NoSuchProjectError
+
+class Command(object):
+  """Base class for any command line action in repo.
+  """
+
+  common = False
+  manifest = None
+  _optparse = None
+
+  @property
+  def OptionParser(self):
+    if self._optparse is None:
+      try:
+        me = 'repo %s' % self.NAME
+        usage = self.helpUsage.strip().replace('%prog', me)
+      except AttributeError:
+        usage = 'repo %s' % self.NAME
+      self._optparse = optparse.OptionParser(usage = usage)
+      self._Options(self._optparse)
+    return self._optparse
+
+  def _Options(self, p):
+    """Initialize the option parser.
+    """
+
+  def Usage(self):
+    """Display usage and terminate.
+    """
+    self.OptionParser.print_usage()
+    sys.exit(1)
+
+  def Execute(self, opt, args):
+    """Perform the action, after option parsing is complete.
+    """
+    raise NotImplementedError
+ 
+  def GetProjects(self, args, missing_ok=False):
+    """A list of projects that match the arguments.
+    """
+    all = self.manifest.projects
+    result = []
+
+    if not args:
+      for project in all.values():
+        if missing_ok or project.Exists:
+          result.append(project)
+    else:
+      by_path = None
+
+      for arg in args:
+        project = all.get(arg)
+
+        if not project:
+          path = os.path.abspath(arg)
+
+          if not by_path:
+            by_path = dict()
+            for p in all.values():
+              by_path[p.worktree] = p
+
+          if os.path.exists(path):
+            while path \
+              and path != '/' \
+              and path != self.manifest.topdir:
+              try:
+                project = by_path[path]
+                break
+              except KeyError:
+                path = os.path.dirname(path)
+          else:
+            try:
+              project = by_path[path]
+            except KeyError:
+              pass
+
+        if not project:
+          raise NoSuchProjectError(arg)
+        if not missing_ok and not project.Exists:
+          raise NoSuchProjectError(arg)
+
+        result.append(project)
+
+    def _getpath(x):
+      return x.relpath
+    result.sort(key=_getpath)
+    return result
+
+class InteractiveCommand(Command):
+  """Command which requires user interaction on the tty and
+     must not run within a pager, even if the user asks to.
+  """
+
+class PagedCommand(Command):
+  """Command which defaults to output in a pager, as its
+     display tends to be larger than one screen full.
+  """