flake with echo of helix editor commands

flake.nix

@@ -20,7 +20,8 @@
         ];
 
         shellHook = ''
-          echo "TeX Live Full environment loaded with LSP support"
+          echo ":sh lualatex --output-directory=main main.tex"
+          echo ":sh zathura main/main.pdf &"
           lualatex --version | head -n 1
         '';
       };