diff --git a/doc/default.nix b/doc/default.nix
index 14c828b02a06..369220dcc536 100644
--- a/doc/default.nix
+++ b/doc/default.nix
@@ -105,14 +105,12 @@ in pkgs.stdenv.mkDerivation {
     ln -s ${optionsDoc.optionsJSON}/share/doc/nixos/options.json ./config-options.json
   '';
 
-  buildPhase = let
-    pythonInterpreterTable = pkgs.callPackage ./doc-support/python-interpreter-table.nix {};
-    pythonSection = with lib.strings; replaceStrings
-      [ "@python-interpreter-table@" ]
-      [ pythonInterpreterTable ]
-      (readFile ./languages-frameworks/python.section.md);
-  in ''
-    cp ${builtins.toFile "python.section.md" pythonSection} ./languages-frameworks/python.section.md
+  pythonInterpreterTable = pkgs.callPackage ./doc-support/python-interpreter-table.nix {};
+
+  passAsFile = [ "pythonInterpreterTable" ];
+
+  buildPhase = ''
+    substituteInPlace ./languages-frameworks/python.section.md --subst-var-by python-interpreter-table "$(<"$pythonInterpreterTablePath")"
 
     cat \
       ./functions/library.md.in \