Environment variables
=====================

``disc`` reads a small, fixed set of environment variables. A command-line
flag always overrides the corresponding variable for that invocation — the
variable only sets the *default*.

oaknut's own variables
----------------------

.. envvar:: OAKNUT_DISC_METADATA_LENS

   Default for the ``--metadata-lens`` option of ``disc ls`` and ``disc
   stat``. Set it to ``addresses`` to show the raw load/exec pair for every
   file, or ``type-date`` to decode a RISC OS filetype and datestamp from it;
   ``auto`` (unset) follows each filing system's own preference. See
   :doc:`metadata`.

.. envvar:: OAKNUT_DISC_RAW_ADDRESSES

   Deprecated alias for :envvar:`OAKNUT_DISC_METADATA_LENS`\ ``=addresses``,
   retained for existing scripts. Set it to ``1`` (or ``true`` / ``yes`` /
   ``on``) to force the raw address reading.

Standard cross-tool variables
-----------------------------

These are widely-honoured conventions, used **unprefixed** on purpose — a tool
that renamed them would not be found by users who set them globally. They
control terminal colour on ``stderr``:

.. envvar:: NO_COLOR

   Any non-empty value disables ANSI colour, per the `NO_COLOR standard
   <https://no-color.org/>`_.

.. envvar:: CLICOLOR

   A value of ``0`` disables ANSI colour.

Colour is also suppressed automatically when ``stderr`` is not a terminal.

.. _env-naming-convention:

Naming convention
-----------------

oaknut's own variables are ``OAKNUT_<TOOL>_<SETTING>`` — upper-case,
underscore-separated, scoped to the tool that reads them (``DISC`` for the
``disc`` CLI), so a future tool can claim its own namespace without collision.
Each is wired to an explicit flag so the two stay in lock-step and a flag can
override the variable per invocation. Standard cross-tool variables such as
:envvar:`NO_COLOR` are deliberately left unprefixed.