diff --git a/profile.d/toolbox.sh b/profile.d/toolbox.sh
index d43f6c7..4e361e0 100644
--- a/profile.d/toolbox.sh
+++ b/profile.d/toolbox.sh
@@ -1,3 +1,5 @@
+# shellcheck shell=sh
+
 [ "$BASH_VERSION" != "" ] || [ "$ZSH_VERSION" != "" ] || return 0
 [ "$PS1" != "" ] || return 0