feat: add help

src/main.rs

@@ -1,7 +1,9 @@
 #[macro_use]
 extern crate rust_util;
+
 use std::path::PathBuf;
 use std::process::Command;
+
 fn main() {
     let home = std::env::var("HOME").unwrap_or_else(|_|
         failure_and_exit!("$HOME not found!")
@@ -20,12 +22,33 @@ fn main() {
     }
     let args = std::env::args().skip(1).collect::<Vec<_>>();
     if args.is_empty() {
-        failure_and_exit!("runrs need arguments, e.g.\n\nrunrs <scirpt.ers> [arguments]\n");
+        failure_and_exit!(
+            "runrs v{}, need arguments, e.g.\n\nrunrs <script.rs> [arguments]\n",
+            env!("CARGO_PKG_VERSION"),
+        );
     }
-    let script_file = match args.get(0) {
+    let first_argument = match args.get(0) {
         None => failure_and_exit!("Must assign file name"),
         Some(f) => f,
     };
+
+    if first_argument == "--help" {
+        println!(r##"{} v{} - {}
+
+Help:
+runrs --help
+
+Run Rust Script:
+runrs <script.rs> [arguments]
+"##,
+                 env!("CARGO_PKG_NAME"),
+                 env!("CARGO_PKG_VERSION"),
+                 env!("CARGO_PKG_DESCRIPTION")
+        );
+        return;
+    }
+
+    let script_file = first_argument;
     let script_content = match std::fs::read_to_string(script_file) {
         Err(e) => failure_and_exit!("Read file: {}, failed: {}", script_file, e),
         Ok(c) => c,