print error chain

src/main.rs

@@ -20,7 +20,7 @@ enum Commands {
     Config(command::config::Commands),
 }
 
-fn main() -> Result<(), command::Error> {
+fn run() -> Result<(), command::Error> {
     let args = Args::parse();
 
     match args.command {
@@ -30,3 +30,22 @@ fn main() -> Result<(), command::Error> {
 
     Ok(())
 }
+
+fn main() {
+    let res = run();
+
+    if let Err(err) = res {       
+        println!("An error occurred!");
+        println!("      raw: {:?}", err);
+        println!("  message: {}", err);
+
+        let mut err: &dyn std::error::Error = &err;
+
+        while let Some(src) = err.source() {
+            println!("caused by: {}", src);
+            err = src;
+        }
+
+        std::process::exit(1);
+    }
+}