export ERL_AFLAGS='-kernel shell_history enabled  -kernel shell_history_path \".erl.history\"'

The above makes iex sessions to store their history on a per-project basis in project directories. ,gitignore should be also updated to include /.erl.history/.

I have already said it few times in different places, but do yourself a favour, and if you are using Git, then have globally (in ~/.config/git/attributes) or per project (in .gitattributes):

mix.lock merge=binary

This will make conflict resolution of mix.lock much easier.

Explanation

This will tell Git to treat Mix lock file as a binary file when doing merges/rebases. This mean, that if there is a conflict, there will be stop (so you need to resolve such conflict), but it will leave file as is (with no conflict markers). This makes my life much easier, as you can then just do mix deps.update --all (as it is most of the time source of such conflicts) and then just git add mix.lock && git rebase --continue.

Handy way to pipe a result from within IEx to your macOS system clipboard when you have pbcopy installed and shell history enabled

defmodule Helpers do
  # pipe expression result to clipboard e.g. ... |> Helpers.copy
  def copy(term) do
    text =
      if is_binary(term) do
        term
      else
        inspect(term, limit: :infinity, pretty: true)
      end

    port = Port.open({:spawn, "pbcopy"}, [])
    true = Port.command(port, text)
    true = Port.close(port)

    IO.inspect(term, label: "copied to clipboard")
    IEx.dont_display_result()
  end
end

Talking about git, I like to configure mine based article: How Core Git Developers Configure Git | Butler's Log. It contains some good info and recommendations you can use to improve the git defaults in your dev env.

One small from me - I’ve added a function in my fish-shell that looks like this:

function dbg
  set test_path $argv[1]
  iex --dbg pry -S mix test $test_path --trace
end

Provided there’s a dbg() macro anywhere in the Elixir code under test, this allows me to enter an interactive debugging session quickly by going from:

mix test test/my_app/permissions/api_test.exs:627

to:

dbg test/my_app/permissions/api_test.exs:627