Specs

shell() :: module()

Returns the current shell.

shell/0 can be used as a wrapper for the current shell. It contains conveniences for requesting information from the user, printing to the shell and so forth. The Mix shell is swappable (see shell/1), allowing developers to use a test shell that simply sends messages to the current process instead of performing IO (see Mix.Shell.Process).

By default, this returns Mix.Shell.IO.

Examples

Mix.shell().info("Preparing to do something dangerous...")

if Mix.shell().yes?("Are you sure?") do
  # do something dangerous
end

Specs

shell(module()) :: :ok

Sets the current shell.

As an argument you may pass Mix.Shell.IO, Mix.Shell.Process, Mix.Shell.Quiet, or any module that implements the Mix.Shell behaviour.

After calling this function, shell becomes the shell that is returned by shell/0.

Examples

iex> Mix.shell(Mix.Shell.IO)
:ok

You can use shell/0 and shell/1 to temporarily switch shells, for example, if you want to run a Mix Task that normally produces a lot of output:

shell = Mix.shell()
Mix.shell(Mix.Shell.Quiet)

try do
  Mix.Task.run("noisy.task")
after
  Mix.shell(shell)
end