diff --git a/nixos/modules/programs/shell.nix b/nixos/modules/programs/shell.nix
index 80d40a7c708c..d8845fd8f446 100644
--- a/nixos/modules/programs/shell.nix
+++ b/nixos/modules/programs/shell.nix
@@ -53,7 +53,7 @@ in
           # Set up a default Nix expression from which to install stuff.
           if [ ! -e $HOME/.nix-defexpr -o -L $HOME/.nix-defexpr ]; then
               rm -f $HOME/.nix-defexpr
-              mkdir $HOME/.nix-defexpr
+              mkdir -p $HOME/.nix-defexpr
               if [ "$USER" != root ]; then
                   ln -s /nix/var/nix/profiles/per-user/root/channels $HOME/.nix-defexpr/channels_root
               fi