message: Replace unwraps with 'let Ok(..) = ...'
diff: @@ -368,17 +368,25 @@ fn execute(shell: &mut Shell, job: &mut RefinedJob, foreground: bool) -> i32 {
  }
  }
  RefinedJob::Builtin { ref name, ref args, ref stdin, ref stdout, ref stderr } => {
  - let stdout_bk = sys::dup(sys::STDOUT_FILENO).unwrap();
  - let stderr_bk = sys::dup(sys::STDERR_FILENO).unwrap();
  - let stdin_bk = sys::dup(sys::STDIN_FILENO).unwrap();
  + if let Ok(stdout_bk) = sys::dup(sys::STDOUT_FILENO) {
  + if let Ok(stderr_bk) = sys::dup(sys::STDERR_FILENO) {
  + if let Ok(stdin_bk) = sys::dup(sys::STDIN_FILENO) {
  let args: Vec<&str> = args
  .iter()
  .map(|x| x as &str).collect();
  - let ret = builtin(shell, name, &args, *stdout, *stderr, *stdin);
  + let code = builtin(shell, name, &args, *stdout, *stderr, *stdin);
  redir(stdout_bk, sys::STDOUT_FILENO);
  redir(stderr_bk, sys::STDERR_FILENO);
  redir(stdin_bk, sys::STDIN_FILENO);
  - ret
  + return code;
  + }
  + let _ = sys::close(stderr_bk);
  + }
  + let _ = sys::close(stdout_bk);
  + }
  + eprintln!("ion: failed to `dup` STDOUT, STDIN, or STDERR: not running '{}'",
  + long);
  + FAILURE
  }
  }
  }
  