feat: friendly error message

src/main.rs

@@ -13,7 +13,14 @@ use clap::{App, AppSettings};
 use cmd::{Command, CommandError};
 use cmd::DefaultCommandImpl;
 
-fn main() -> CommandError {
+
+fn main() {
+    if let Err(e) = inner_main() {
+        failure_and_exit!("Run cli error: {}", e);
+    }
+}
+
+fn inner_main() -> CommandError {
     let commands: Vec<Box<dyn Command>> = vec![
         Box::new(register::CommandImpl),
         Box::new(sign::CommandImpl),