If you've ever used irb, node or pretty much any other command line REPL, you probably really miss being able to use the up and down keys to recall your last commands from a previous session in iex.
Today I discovered a package which hacks this functionality into the Erlang shell, and thus also works for Elixir.
It's very simple to install:
git clone [email protected]:ferd/erlang-history.git
cd erlang-history
make install
Note that you may need to run the last line as sudo make install depending how and where you installed Erlang/Elixir. I needed to do this, and I installed Erlang with Homebrew on OS X.
Enjoy!