diff --git a/doc_src/cmds/export.rst b/doc_src/cmds/export.rst
index de62f8f6a..8ca11eefe 100644
--- a/doc_src/cmds/export.rst
+++ b/doc_src/cmds/export.rst
@@ -36,6 +36,13 @@ The following commands have an identical effect.
     set -gx PAGER bat
     export PAGER=bat
 
+Note: If you want to add to e.g. ``$PATH``, you need to be careful to :ref:`combine the list <cartesian-product>`. Quote it, like so::
+
+    export PATH="$PATH:/opt/bin"
+
+Or just use ``set``, which avoids this::
+
+    set -gx PATH $PATH /opt/bin
 
 See more
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