Do not panic if command line have unreconginzed option.

Return 1 if no command is parsed.

.gitignore

@@ -2,3 +2,4 @@
 /proc_macros/target
 .vscode/
 test/
+.workspace/

src/main.rs

@@ -112,7 +112,7 @@ impl Main {
     pub fn run(&mut self) -> i32 {
         self.cmd = opts::parse_cmd();
         if self.cmd.is_none() {
-            return 0;
+            return 1;
         }
         let cmd = self.cmd.as_ref().unwrap();
         self.settings = Some(SettingStore::default());

src/opts.rs

@@ -191,7 +191,8 @@ pub fn parse_cmd() -> Option<CommandOpts> {
     let result = match opts.parse(&argv[1..]) {
         Ok(m) => m,
         Err(err) => {
-            panic!("{}", err.to_string())
+            println!("{}", err.to_string());
+            return None;
         }
     };
     if result.opt_present("h") || result.free.len() == 0 {