diff --git a/.circleci/config.yml b/.circleci/config.yml
index 64213551684be490be5affec135b9685cd73fcaf..e9c7d6a131e826e10646e207b5c2e7b25815ad0e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -145,9 +145,9 @@ jobs:
 
       - run:
           name: "Report Coverage"
-          shell: "nix-shell"
           command: |
-            #! nix-shell -p 'python.withPackages (ps: [ ps.codecov ])'
+            #! /usr/bin/env nix-shell
+            #! nix-shell -p "python.withPackages (ps: [ ps.codecov ])"
             cp ./result-doc/share/doc/*/.coverage ./
             python -m coverage combine
             python -m coverage report