message: Create file when appending
diff: @@ -29,7 +29,7 @@ pub fn execute_pipeline(pipeline: &mut Pipeline) -> i32 {
  if let Some(ref stdout) = pipeline.stdout {
  if let Some(mut command) = piped_commands.last_mut() {
  let file = if stdout.append {
  - OpenOptions::new().write(true).append(true).open(&stdout.file)
  + OpenOptions::new().create(true).write(true).append(true).open(&stdout.file)
  } else {
  File::create(&stdout.file)
  };
  