Handles executing the command on the shell and consumes and returns
		the returned information (stdout)

		:param command:
			The command argument list to execute.
			It should be a string, or a sequence of program arguments. The
			program to execute is the first item in the args sequence or string.

		:param istream:
			Standard input filehandle passed to subprocess.Popen.

		:param with_keep_cwd:
			Whether to use the current working directory from os.getcwd().
			The cmd otherwise uses its own working_dir that it has been initialized
			with if possible.

		:param with_extended_output:
			Whether to return a (status, stdout, stderr) tuple.

		:param with_exceptions:
			Whether to raise an exception when git returns a non-zero status.

		:param as_process:
			Whether to return the created process instance directly from which 
			streams can be read on demand. This will render with_extended_output and 
			with_exceptions ineffective - the caller will have 
			to deal with the details himself.
			It is important to note that the process will be placed into an AutoInterrupt
			wrapper that will interrupt the process once it goes out of scope. If you 
			use the command in iterators, you should pass the whole process instance 
			instead of a single stream.
			
		:param output_stream:
			If set to a file-like object, data produced by the git command will be 
			output to the given stream directly.
			This feature only has any effect if as_process is False. Processes will
			always be created with a pipe due to issues with subprocess.
			This merely is a workaround as data will be copied from the 
			output pipe to the given output stream directly.
			
		:param subprocess_kwargs:
			Keyword arguments to be passed to subprocess.Popen. Please note that 
			some of the valid kwargs are already set by this method, the ones you 
			specify may not be the same ones.
			
		:return:
			* str(output) if extended_output = False (Default)
			* tuple(int(status), str(stdout), str(stderr)) if extended_output = True
			 
			if ouput_stream is True, the stdout value will be your output stream:
			* output_stream if extended_output = False
			* tuple(int(status), output_stream, str(stderr)) if extended_output = True
			
		:raise GitCommandError:
		
		:note:
		   If you add additional keyword arguments to the signature of this method, 
		   you must update the execute_kwargs tuple housed in this module.

def execute(self, command,
				istream=None,
				with_keep_cwd=False,
				with_extended_output=False,
				with_exceptions=True,
				as_process=False, 
				output_stream=None, 
				**subprocess_kwargs
				):
		"""Handles executing the command on the shell and consumes and returns
		the returned information (stdout)

		:param command:
			The command argument list to execute.
			It should be a string, or a sequence of program arguments. The
			program to execute is the first item in the args sequence or string.

		:param istream:
			Standard input filehandle passed to subprocess.Popen.

		:param with_keep_cwd:
			Whether to use the current working directory from os.getcwd().
			The cmd otherwise uses its own working_dir that it has been initialized
			with if possible.

		:param with_extended_output:
			Whether to return a (status, stdout, stderr) tuple.

		:param with_exceptions:
			Whether to raise an exception when git returns a non-zero status.

		:param as_process:
			Whether to return the created process instance directly from which 
			streams can be read on demand. This will render with_extended_output and 
			with_exceptions ineffective - the caller will have 
			to deal with the details himself.
			It is important to note that the process will be placed into an AutoInterrupt
			wrapper that will interrupt the process once it goes out of scope. If you 
			use the command in iterators, you should pass the whole process instance 
			instead of a single stream.
			
		:param output_stream:
			If set to a file-like object, data produced by the git command will be 
			output to the given stream directly.
			This feature only has any effect if as_process is False. Processes will
			always be created with a pipe due to issues with subprocess.
			This merely is a workaround as data will be copied from the 
			output pipe to the given output stream directly.
			
		:param subprocess_kwargs:
			Keyword arguments to be passed to subprocess.Popen. Please note that 
			some of the valid kwargs are already set by this method, the ones you 
			specify may not be the same ones.
			
		:return:
			* str(output) if extended_output = False (Default)
			* tuple(int(status), str(stdout), str(stderr)) if extended_output = True
			 
			if ouput_stream is True, the stdout value will be your output stream:
			* output_stream if extended_output = False
			* tuple(int(status), output_stream, str(stderr)) if extended_output = True
			
		:raise GitCommandError:
		
		:note:
		   If you add additional keyword arguments to the signature of this method, 
		   you must update the execute_kwargs tuple housed in this module."""
		if GIT_PYTHON_TRACE and not GIT_PYTHON_TRACE == 'full':
			print ' '.join(command)

		# Allow the user to have the command executed in their working dir.
		if with_keep_cwd or self._working_dir is None:
		  cwd = os.getcwd()
		else:
		  cwd=self._working_dir
		  
		# Start the process
		proc = Popen(command,
						cwd=cwd,
						stdin=istream,
						stderr=PIPE,
						stdout=PIPE,
						close_fds=(os.name=='posix'),# unsupported on linux
						**subprocess_kwargs
						)
		if as_process:
			return self.AutoInterrupt(proc, command)
		
		# Wait for the process to return
		status = 0
		stdout_value = ''
		stderr_value = ''
		try:
			if output_stream is None:
				stdout_value, stderr_value = proc.communicate() 
				# strip trailing "\n"
				if stdout_value.endswith("\n"):
					stdout_value = stdout_value[:-1]
				if stderr_value.endswith("\n"):
					stderr_value = stderr_value[:-1]
				status = proc.returncode
			else:
				stream_copy(proc.stdout, output_stream, self.max_chunk_size)
				stdout_value = output_stream
				stderr_value = proc.stderr.read()
				# strip trailing "\n"
				if stderr_value.endswith("\n"):
					stderr_value = stderr_value[:-1]
				status = proc.wait()
			# END stdout handling
		finally:
			proc.stdout.close()
			proc.stderr.close()

		if GIT_PYTHON_TRACE == 'full':
			cmdstr = " ".join(command)
			if stderr_value:
				print "%s -> %d; stdout: '%s'; stderr: '%s'" % (cmdstr, status, stdout_value, stderr_value)
			elif stdout_value:
				print "%s -> %d; stdout: '%s'" % (cmdstr, status, stdout_value)
			else:
				print "%s -> %d" % (cmdstr, status)
		# END handle debug printing

		if with_exceptions and status != 0:
			raise GitCommandError(command, status, stderr_value)

		# Allow access to the command's status code
		if with_extended_output:
			return (status, stdout_value, stderr_value)
		else:
			return stdout_value