> ## Documentation Index > Fetch the complete documentation index at: https://flox.dev/docs/llms.txt > Use this file to discover all available pages before exploring further. # The default environment > Using Flox as your system package manager In the typical development case you would create a directory for your project. `flox init` to create an environment for it, then `flox activate` in that directory when you want to work on that project. The packages in that environment are available when the environment is active, and they're unavailable otherwise. But what about packages that you *always* want available? Without Flox, you may turn to your system's package manager (`apt`, `yum`, `brew`, etc) in order to install packages system-wide. This has a number of drawbacks: * You often only have a single package version to choose from. * You often can't install multiple versions of a package side-by-side. * You can't ensure that multiple machines get the exact same version. * You may not be able to back up the list of installed packages. The Flox `default` environment doesn't have these problems, so let's take a look at how to set it up. ## Initial setup At the most basic level, the `default` environment is simply an environment called `default`. `default` environments are typically [shared via FloxHub](/tutorials/sharing-environments), but you can also manage environments with git. We refer to the environment associated with your user account as *your* `default` environment. In some cases Flox will prompt to set up your `default` environment for you. To create the `default` environment yourself, make sure you are logged in to FloxHub, and initialize a FloxHub environment under your account: ```console theme={null} $ flox auth status || flox auth login ✔ Authentication complete ✔ Logged in as ``` ```bash theme={null} flox init -D ``` **Shorthand for default environment** You can use `-D` or `--default` as a shorthand for `-r /default`. For example: `flox init -D` is equivalent to `flox init -r /default`. Once the environment has been created, configure your shell to activate the environment with every new shell. This can be done as part of the automatic setup, or you can add a single line to your shell's RC file: Depending on the context, Bash will load different startup files. For that reason, we need to add a line to two different files: `.bashrc` and `.profile`. Add the following line to the very end of each of those files: ``` eval "$(flox activate -D -m run)" ``` Add the following line to the very end of your `.zprofile` and `.zshrc` files: ``` eval "$(flox activate -D -m run)" ``` Add the following line to the very end of your `config.fish` file: ``` flox activate -D -m run | source ``` Add the following line to the very end of your `.tcshrc` file: **For FloxHub environments:** ``` eval "`flox activate -D -m run`" ``` *** Once you've added that line to your shell, you'll need to restart your shell (or open a new one) for the changes to take effect. If you don't want to activate it automatically from your shell initialization scripts, you can activate the default environment explicitly when needed: ```bash theme={null} flox activate -D ``` ## Taking it for a spin Now let's test out your new `default` environment. If you're in an arbitrary directory and `apt install hello` you would expect it to be available no matter what directory you're in. Let's do the same with Flox. Let's create a new temporary directory that we know doesn't have an environment in it. ```bash theme={null} cd $(mktemp -d) ``` Now we'll install a package and see that it gets installed to the `default` environment, like you would expect from your system's package manager: ```console theme={null} $ flox install hello ✔ 'hello' installed to environment 'default' ``` ## Installing packages to the default environment from another Flox environment If you're in a project directory with an existing Flox environment, unsurprisingly, running `flox install ` will install the package to the environment in that directory, rather than your default environment. Nevertheless, it's still easy to install whatever you wish to your `default` environment. You can use the `-D` (or `--default`) flag as a shorthand: ```bash theme={null} flox install -D hello ``` When you do this, you should see the following output, indicating success: ```console theme={null} ✔ 'hello' installed to environment 'default' ``` ## Customization Depending on when you created your default environment (the default was changed recently), you may also see `flox [default]` as part of your prompt for every new shell. You can configure that with a single command: ``` flox config --set hide_default_prompt false ``` ``` flox config --set hide_default_prompt true ``` *** ## Sharing Since the `default` environment is "just" another [FloxHub environment](/tutorials/sharing-environments), it's possible to push this environment and share it between machines. In fact, activating or initializing default environments on other machines will link to the environment that is already on FloxHub. To use the environment on other machines simply log in and add the activation to your dotfiles as described above. Changes made to the environment locally (e.g. newly installed packages) can be synchronized with [`flox push`](/man/flox-push) and [`pull`](/man/flox-pull). *** ## Generations Pushing an environment creates the first version of the environment tracked on FloxHub, which is called a generation. To see how generations can be used to undo changes, edit the environment, perhaps adding a variable `FOO = "bar"` to the `[vars]` section. Then push the environment to FloxHub: ```bash theme={null} flox edit && flox push ``` This should print a link to your environment on FloxHub. Follow the link and click the `Generations` tab. This should show the most recent generation created by the `flox edit` command. To revert to the version of the environment prior to the edit, run rollback: ```bash theme={null} flox generations rollback && flox push ``` Now if you run `flox pull` on another host, you'll get the rolled-back environment, without the edit. *** ## Conclusion Whether you want a reproducible package manager for your whole system, or you want reproducible, cross-platform developer environments, Flox has you covered. Even better, if you want both a package manager *and* developer environments, with Flox you only need to learn one tool. *** ## Detached and directory based `default` environments Since `default` environments are normal Flox environments, you can use any other environment the same way. For example, you can: Initialize a local environment, e.g. in your home directory: ```bash theme={null} flox init --dir ~ ``` Start with a template on FloxHub: ```bash theme={null} flox pull --copy --dir ~ owner/name ``` Use a directory-based FloxHub environment: ```bash theme={null} flox pull --dir ~ owner/name ``` *** If you choose to automatically activate the environment in your rc files, change the `flox activate -r ` accordingly to e.g. `flox activate --dir ~`.