diff --git a/doc/manual/src/command-ref/nix-shell.md b/doc/manual/src/command-ref/nix-shell.md
index 8c77923d0..88b675e71 100644
--- a/doc/manual/src/command-ref/nix-shell.md
+++ b/doc/manual/src/command-ref/nix-shell.md
@@ -41,10 +41,12 @@ to `nix-shell`. For example, the derivation attribute
 shellHook =
   ''
     echo "Hello shell"
+    export SOME_API_TOKEN="$(cat ~/.config/some-app/api-token)"
   '';
 ```
 
-will cause `nix-shell` to print `Hello shell`.
+will cause `nix-shell` to print `Hello shell` and set the `SOME_API_TOKEN`
+environment variable to a user-configured value.
 
 # Options