From d5f6f4b12ddf81100bb684dbeced39cc0c6629c4 Mon Sep 17 00:00:00 2001
From: Dave Wapstra <dwapstra@cisco.com>
Date: Fri, 17 Apr 2026 10:00:01 +1200
Subject: [PATCH] Add description of pyats configuration environment variable
 usage

---
 docs/configuration/index.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/docs/configuration/index.rst b/docs/configuration/index.rst
index f29bb42..766a07f 100644
--- a/docs/configuration/index.rst
+++ b/docs/configuration/index.rst
@@ -46,6 +46,18 @@ Each INI file content is standardized to use:
 - ``=`` as key/value delimiter
 - ``#`` for comments.
 
+INI values also support environment variable expansion via standard shell-style
+references such as ``$VAR`` and ``${VAR}``.
+
+.. code-block:: ini
+
+    [easypy]
+    runinfo.directory = $HOME/work/pyats/runinfo
+    runinfo.archive = $ARCHIVE_ROOT/pyats
+
+If an environment variable referenced in ``pyats.conf`` is not set, pyATS logs
+a warning and substitutes an empty string.
+
 .. note::
 
     do not use quotes around strings in INI files - see