feat 处理命令行输入.

src/main.rs

@@ -1,3 +1,16 @@
-fn main() {
-    println!("Hello, world!");
+mod merge;
+
+use std::env;
+use std::error::Error;
+use std::io::Result;
+use std::path::PathBuf;
+
+fn main() -> Result<()> {
+    let args: Vec<String> = env::args().collect();
+    let merge_path = if args.len() > 1 {
+        PathBuf::from(args[1].as_str())
+    } else {
+        PathBuf::from(".")
+    };
+    merge::merge_video_from_path(&merge_path)
 }