Frequently Asked Questions¶
Does VirtualFish work with Python 3? What about PyPy?¶
Yes! In fact, you can create Python 3 virtual environments even if your
system Python is Python 2, or vice versa, using the
(see the Usage section for full details).
Why does VirtualFish use Virtualenv and not Python’s built-in
Virtualenv can create both Python 2 and Python 3 virtual environments, whereas
venv module can only create Python 3 virtual environments.
That said, since Python 2 is no longer officially supported by the Python
Software Foundation, Python 2 support is a very minor consideration when
deciding which tool to use. The main reason VirtualFish uses Virtualenv is due
to its much faster speed. We have seen Virtualenv create environments in
one-fifth the amount of time that the
venv module takes to perform the
Why doesn’t VirtualFish use activate.fish?¶
VirtualFish uses its own internal virtualenv activation code instead of the
activate.fish file that comes with every virtualenv for two main reasons.
One is that when VirtualFish was originally written,
actually work. The second reason, which is still valid today, is that
activate.fish tries to modify your
fish_prompt is a function and not a variable like in most other
shells, modifying it programmatically is not trivial, and the way that
Virtualenv accomplishes it is more than a little hacky. The benefit of it being
a function is that the syntax for customising it is much less terse and cryptic
PS1 on Bash. This is why VirtualFish doesn’t attempt to modify
your prompt, and instead tells you how to do it yourself.