## 46.11. Environment Variables

 Some of the environment variables that are accepted by the Python interpreter can also be used to affect PL/Python behavior. They would need to be set in the environment of the main PostgreSQL server process, for example in a start script. The available environment variables depend on the version of Python; see the Python documentation for details. At the time of this writing, the following environment variables have an affect on PL/Python, assuming an adequate Python version:

* `PYTHONHOME`

* `PYTHONPATH`

* `PYTHONY2K`

* `PYTHONOPTIMIZE`

* `PYTHONDEBUG`

* `PYTHONVERBOSE`

* `PYTHONCASEOK`

* `PYTHONDONTWRITEBYTECODE`

* `PYTHONIOENCODING`

* `PYTHONUSERBASE`

* `PYTHONHASHSEED`

 (It appears to be a Python implementation detail beyond the control of PL/Python that some of the environment variables listed on the `python` man page are only effective in a command-line interpreter and not an embedded Python interpreter.)

