Rust io::stdin to get set directory

Question

I'm new to Rust and have been fighting with this for a while now and I'm sure there's just something about the language that I'm missing. So please excuse me if this obvious.

I'm using the io::stdin().read_line() to get a path/directory inputed from the user and then use that to loop through the files and/or directories in that entered path.

I'm also setting default path for if the user doesn't enter anything. For this I'm using env::current_dir(). When I use this default value fs::read_dir() works fine, but when I try to use the variable set by the user input the system does a panic while running.

let current_directory = env::current_dir().unwrap().display().to_string();
let mut new_directory = String::new();

io::stdin().read_line(&mut new_directory)
    .expect("Failed to read line");

let dir = if new_directory == "\n" {
    current_directory
} else {
    new_directory
};

let paths = fs::read_dir(dir).unwrap();

for path in paths {
    println!("Name: {}", path.unwrap().path().display());
}

As I mentioned I get a panic when it hits the fs::read_dir(dir) line while the program is running not during while it's compiling.

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 2, message: "No such file or directory" } }', src/libcore/result.rs:860:4
note: Run with `RUST_BACKTRACE=1` for a backtrace.

and just incase it helps, here's with the backtrace:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 2, message: "No such file or directory" } }', src/libcore/result.rs:860:4
stack backtrace:
  0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
  1: std::panicking::default_hook::{{closure}}
  2: std::panicking::default_hook
  3: std::panicking::rust_panic_with_hook
  4: std::panicking::begin_panic_new
  5: std::panicking::begin_panic_fmt
  6: rust_begin_unwind
  7: core::panicking::panic_fmt
  8: core::result::unwrap_failed
  9: <core::result::Result<T, E>>::unwrap
  10: quad_videos::main
  11: __rust_maybe_catch_panic
  12: std::rt::lang_start
  13: main

Thanks in advance

I think it's because you have the new line char at the end of user input, try `new_directory.trim().to_string()`. BTW, rust can't prevent IO errors at compile time, that why almost all IO related code use results. — Grégory OBANOS, Oct 09 '17 at 08:32
As @GrégoryOBANOS already said: the line you read contains the new-line character at the end. You can remove it by using `str::trim()` (as mentioned in the linked answer). I would recommend you to use `trim()` before checking if the user entered anything (before your `== "\n"` test). With `trim()` you can simple check `if new_directory.is_empty()` which also works on other platforms with line endings different from `'\n'`. — Lukas Kalbertodt, Oct 09 '17 at 08:57

Rust io::stdin to get set directory

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