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The fyn installer

Changing the installation path

By default, fyn is installed in the user executable directory. Download install.sh or install.ps1 from a GitHub release first, then run it with the following environment variables.

To change the installation path, use UV_INSTALL_DIR:

$ env UV_INSTALL_DIR="/custom/path" sh install.sh

PS> $env:UV_INSTALL_DIR = "C:\Custom\Path"; powershell -ExecutionPolicy ByPass -File .\install.ps1

Note

Changing the installation path only affects where the fyn binary is installed. fyn will still store its data (cache, Python installations, tools, etc.) in the default locations. See the storage reference for details on these locations and how to customize them.

Disabling shell modifications

The installer may also update your shell profiles to ensure the fyn binary is on your PATH. To disable this behavior, use UV_NO_MODIFY_PATH. For example:

$ env UV_NO_MODIFY_PATH=1 sh install.sh

If installed with UV_NO_MODIFY_PATH, subsequent operations, like fyn self update, will not modify your shell profiles.

Unmanaged installations

In ephemeral environments like CI, use UV_UNMANAGED_INSTALL to install fyn to a specific path while preventing the installer from modifying shell profiles or environment variables:

$ env UV_UNMANAGED_INSTALL="/custom/path" sh install.sh

The use of UV_UNMANAGED_INSTALL will also disable self-updates (via fyn self update).

Passing options to the installation script

Using environment variables is recommended because they are consistent across platforms. However, options can be passed directly to the installation script. For example, to see the available options:

$ sh install.sh --help