USD provides Python bindings for most of its libraries. In these tutorials, we will be using these bindings almost exclusively. Ensure the following environment variables are set so that Python can locate these bindings. |Environment Variable|Meaning|Value| |---|---|---| |PYTHONPATH|This is a path list which Python uses to find modules.|$PYTHONPATH:**USD_INSTALL_ROOT/lib/python/**| Some tools in the [USD Toolset](https://openusd.org/docs/USD-Toolset.html) rely on one another. For example, usddiff relies on usdcat for converting binary usd files into ascii. For this reason, these tools must be available on your PATH. |Environment Variable|Meaning|Value| |---|---|---| |PATH|This is a path which *nix systems use to find applications.|$PATH:**USD_INSTALL_ROOT/bin/**| For more information see our page on [Advanced Build Configuration](https://github.com/PixarAnimationStudios/USD/blob/master/BUILDING.md).