Method prefix

invoke/context.py:281–334

Prefix all nested `run`/`sudo` commands with given command plus ``&&``. Most of the time, you'll want to be using this alongside a shell script which alters shell state, such as ones which export or alter shell environment variables. For example, one of the

(self, command: str)

    @contextmanager
    def prefix(self, command: str) -> Generator[None, None, None]:
        """
        Prefix all nested `run`/`sudo` commands with given command plus ``&&``.

        Most of the time, you'll want to be using this alongside a shell script
        which alters shell state, such as ones which export or alter shell
        environment variables.

        For example, one of the most common uses of this tool is with the
        ``workon`` command from `virtualenvwrapper
        <https://virtualenvwrapper.readthedocs.io/en/latest/>`_::

            with c.prefix('workon myvenv'):
                c.run('./manage.py migrate')

        In the above snippet, the actual shell command run would be this::

            $ workon myvenv && ./manage.py migrate

        This context manager is compatible with `cd`, so if your virtualenv
        doesn&#x27;t ``cd`` in its ``postactivate`` script, you could do the
        following::

            with c.cd('/path/to/app'):
                with c.prefix('workon myvenv'):
                    c.run('./manage.py migrate')
                    c.run('./manage.py loaddata fixture')

        Which would result in executions like so::

            $ cd /path/to/app && workon myvenv && ./manage.py migrate
            $ cd /path/to/app && workon myvenv && ./manage.py loaddata fixture

        Finally, as alluded to above, `prefix` may be nested if desired, e.g.::

            with c.prefix('workon myenv'):
                c.run('ls')
                with c.prefix('source /some/script'):
                    c.run('touch a_file')

        The result::

            $ workon myenv && ls
            $ workon myenv && source /some/script && touch a_file

        Contrived, but hopefully illustrative.

        .. versionadded:: 1.0
        """
        self.command_prefixes.append(command)
        try:
            yield
        finally:
            self.command_prefixes.pop()

    @property
    def cwd(self) -> str: