Bootstrap Go CLI shell

internal/cli/run.go

@@ -0,0 +1,30 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+)
+
+const usage = "Usage:\n  notarius help\n"
+
+// Run executes the command-line interface and returns a process exit code.
+func Run(args []string, stdout, stderr io.Writer) int {
+	if len(args) == 0 {
+		writeUsage(stdout)
+		return 0
+	}
+
+	switch args[0] {
+	case "help", "--help", "-h":
+		writeUsage(stdout)
+		return 0
+	default:
+		fmt.Fprintf(stderr, "notarius: unknown command %q\n", args[0])
+		writeUsage(stderr)
+		return 2
+	}
+}
+
+func writeUsage(w io.Writer) {
+	fmt.Fprint(w, usage)
+}