diff --git a/sh/main.sh b/sh/main.sh
index 692664a..4c99298 100644
--- a/sh/main.sh
+++ b/sh/main.sh
@@ -26,16 +26,13 @@ _sh_ifs_pop() {
 }
 
 _sh_main_log() {
-	case "${-}" in
-	*i*)
+	if sh_shell_interactive; then
 		[ ${#} -gt 0 ] || set -- ""
 		local line
 		for line in "${@}"; do
 			echo "${line}"
 		done
-		;;
-	*) ;;
-	esac
+	fi
 }
 
 # public
@@ -115,10 +112,12 @@ sh_main() {
 		return 1
 	fi
 	sh_source_directory "${SH_USER}"
-	sh_log
-	sh_shellcheck "${SH_ROOT}"
-	sh_log
-	sh_help
+	if sh_shell_interactive; then
+		sh_log
+		sh_shellcheck "${SH_ROOT}"
+		sh_log
+		sh_help
+	fi
 }
 
 sh_main