message: Turn on initial shared history options.
diff: @@ -14,7 +14,7 @@ use ion_shell::{
  };
  use itertools::Itertools;
  use liner::{Buffer, Context, KeyBindings};
  -use std::{cell::RefCell, path::Path, rc::Rc};
  +use std::{io, io::Write, cell::RefCell, path::Path, rc::Rc};
  pub const MAN_ION: &str = "NAME
  Ion - The Ion shell
  @@ -119,7 +119,37 @@ impl<'a> InteractiveBinary<'a> {
  return Status::SUCCESS;
  }
  + match args.get(1).map(|s| s.as_str()) {
  + Some("+inc_append") => {
  + context_bis.borrow_mut().history.inc_append = true;
  + }
  + Some("-inc_append") => {
  + context_bis.borrow_mut().history.inc_append = false;
  + }
  + Some("+share") => {
  + context_bis.borrow_mut().history.inc_append = true;
  + context_bis.borrow_mut().history.share = true;
  + }
  + Some("-share") => {
  + context_bis.borrow_mut().history.inc_append = false;
  + context_bis.borrow_mut().history.share = false;
  + }
  + Some("+duplicates") => {
  + context_bis.borrow_mut().history.load_duplicates = true;
  + }
  + Some("-duplicates") => {
  + context_bis.borrow_mut().history.load_duplicates = false;
  + }
  + Some(_) => {
  + Status::error("Invalid history option. Choices are [+|-] inc_append and share (implies inc_append).");
  + }
  + None => {
  print!("{}", context_bis.borrow().history.buffers.iter().format("\n"));
  + io::stdout().flush().unwrap_or_else(|err| {
  + eprintln!("ion: history print: {}", err);
  + });
  + }
  + }
  Status::SUCCESS
  };
  