I usually manage my system-wide Python installation with the system's package manager, and avoid using Python's own package manager [pip.](https://en.wikipedia.org/wiki/Pip_(package_manager)) Not so in a virtual environment. As described in a [previous post,](http://pdes-net.org/cobra/posts/install-a-python-based-blog.html) pip, together with the pip-tools, offers a very convenient way to get and to keep all tools in your virtual environment up to date. Imagine my surprise when a couple of months ago 'pip-review --interactive' did not update my tools one by one, as it used to do, but only resulted in a 'fish: Unknown command 'pip-review'. As it turned out, the developer of pip-tools (which I dutifully kept up to date) had decided to dump pip-review in favor of two new commands, [pip-compile and pip-sync](http://nvie.com/posts/pip-tools-10-released/). I'm sure he had good reasons for that, and it's really no big deal for end-users like me. After a 'pip list' I knew what I needed, created a corresponding requirements.in as Vincent described in [his post](http://nvie.com/posts/pip-tools-10-released/), and ran pip-compile requirements.in && pip-sync requirements.txt That's all. It's still as useful as ever.