refactor: fix clippy warnings

user/src/bin/cat.rs

@@ -30,7 +30,7 @@ fn main() -> i32 {
 
     if args.len() == 1 {
         if let Err(e) = do_cat(io::stdin()) {
-            eprintln!("{}: {:?}", ".", e);
+            eprintln!(".: {:?}", e);
             res = -1;
         }
     } else {

user/src/bin/hexd.rs

@@ -27,7 +27,7 @@ fn line_print(off: usize, line: &[u8]) {
             print!(".");
         }
     }
-    println!("");
+    println!();
 }
 
 fn do_hexd<F: Read>(mut fd: F) -> Result<(), io::Error> {
@@ -53,7 +53,7 @@ fn main() -> i32 {
 
     if args.len() == 1 {
         if let Err(e) = do_hexd(io::stdin()) {
-            eprintln!("{}: {:?}", ".", e);
+            eprintln!(".: {:?}", e);
             res = -1;
         }
     } else {

user/src/bin/ls.rs

@@ -57,7 +57,7 @@ fn main() -> i32 {
 
     if args.len() == 1 {
         if let Err(e) = list_directory(".") {
-            eprintln!("{}: {:?}", ".", e);
+            eprintln!(".: {:?}", e);
             res = -1;
         }
     } else {

user/src/bin/shell.rs

@@ -22,13 +22,11 @@ fn cmd_cd(args: &[&str]) -> ExitCode {
     if args.len() != 2 {
         eprintln!("Usage: cd DIR");
         ExitCode::from(-1)
+    } else if let Err(err) = sys_chdir(args[1]) {
+        eprintln!("{}: {:?}", args[1], err);
+        ExitCode::from(-1)
     } else {
-        if let Err(err) = sys_chdir(args[1]) {
-            eprintln!("{}: {:?}", args[1], err);
-            ExitCode::from(-1)
-        } else {
-            ExitCode::from(0)
-        }
+        ExitCode::from(0)
     }
 }
 

user/src/init/main.rs

@@ -30,6 +30,6 @@ fn main() -> i32 {
         }
     } else {
         sys_execve("/sbin/login", &["/sbin/login", "/dev/ttyS0"]).unwrap();
-        loop {}
+        unreachable!();
     }
 }