iex - Man Page

The Elixir shell

Examples (TL;DR)

Start an interactive session: iex
Start a session that remembers history: iex --erl "-kernel shell_history enabled"
Start and load Mix project files: iex -S mix

The interactive shell is used for evaluation, debugging and introspection of the Elixir runtime system. It is also possible to use the program for testing the work of small pieces of code escaping the stage of saving the code in a file.

Options

Note that many of the options mentioned here were borrowed from the Erlang shell, therefore erl(1) can be used as an additional source of information on the options.

-h, --help

Displays the help message to the standard error (stderr) and exits.

-v, --version

Displays the Elixir version to the standard output (stdout) and exits.

-e, --eval expression

Evaluates the specified expression (see the --rpc-eval option).

-r file

Requires the specified file. In other words, the file is checked for existence at the start of iex.

-S script

Runs the specified script.

-pa directory

Adds the specified directory to the beginning of the code path. If the directory already exists, it will be removed from its old position and put to the beginning.

See also the function Code.prepend_path/1.

-pr file

Does the same thing as -r (see above) but in parallel.

-pz directory

Adds the specified directory to the end of the code path. If the directory already exists, it will be neither removed from its old position nor put to the end.

See also the function Code.append_path/1.

--app application

Starts the specified application and all its dependencies.

--boot file

Specifies the name of the boot file, file.boot, which is used to start the system. Unless File contains an absolute path, the system searches for file.boot in the current and $ROOT/bin directories.

Defaults to $ROOT/bin/start.boot.

The option is equivalent to Erlang's -boot.

--boot-var var dir

If the boot script contains a path variable var other than $ROOT, this variable is expanded to dir. Used when applications are installed in another directory than $ROOT/lib.

The option is equivalent to Erlang's -boot_var.

See also the function :systools.make_script/1,2 in SASL.

--erl parameters

Serves the same purpose as ELIXIR_ERL_OPTIONS (see the Environment section)

--erl-config file

Specifies the name of a configuration file, file.config, which is used to configure applications. Note that the configuration file must be written in Erlang.

The option is equivalent to Erlang's -config.

--cookie value

Specifies the magic cookie value. If the value isn't specified via the option when the node starts, it will be taken from the file ~/.erlang.cookie (see the Files section). Distributed nodes can interact with each other only when their magic cookies are equal.

See also the function Node.set_cookie/2.

--hidden

Starts a hidden node.

Connections between nodes are transitive. For example, if node A is connected to node B, and node B is connected to node C, then node A is connected to node C. The option --hidden allows creating a node which can be connected to another node, escaping redundant connections.

The function Node.list/0 allows getting the list of nodes connected to the target node; however, the list won't include hidden nodes. Depending on the input parameter, the function Node.list/1 allows getting the list which contains only hidden nodes (the parameter :hidden) or both hidden and not hidden nodes (the parameter :connected).

--logger-otp-reports val

Enables or disables OTP reporting (val can be either true or false).

--logger-sasl-reports val

Enables or disables SASL reporting (val can be either true or false).

--sname name

Gives a node a short name and starts it. Short names take the form of name@host, where host is the name of the target host (hostname(1)) which runs the node. The nodes with short names can interact with each other only in the same local network.

--name name

Gives a node a long name and starts it. Long names take the form of name@host, where host is the IP address of the host which runs the node. In contrast to the nodes with short names, the nodes with long names aren't limited by boundaries of a local network (see above).

--pipe-to pipedir logdir

Starts the Erlang VM as a named pipedir and logdir (only for Unix-like operating systems).

--rpc-eval node expression

Evaluates the specified expression on the specified node (see the --eval option).

--vm-args file

Reads the command-line arguments from file and passes them to the Erlang VM.

The option is equivalent to Erlang's -args_file.

--werl

Uses Erlang's Windows shell GUI (only for Windows).

--dot-iex file

Loads the specified file instead of .iex.exs (see the Files section).

--remsh node

Connects to the specified node which was started with the --sname or --name options (see above).

--

Separates the options passed to the compiler from the options passed to the executed code.

Notes

The following options can be given more than once: --boot-var, --erl-config, --eval, --rpc-eval.

Environment

ELIXIR_ERL_OPTIONS: Allows passing parameters to the Erlang runtime.

Files

~/.erlang.cookie: Stores the magic cookie value which is used only when it wasn't specified via the option --cookie (see above). If the file doesn't exist when a node starts, it will be created.
.iex.exs: After iex starts, it seeks the file .iex.exs and, in a case of success, executes the code from the file in the context of the shell. At first the search starts in the current working directory; then, if necessary, it continues in the home directory.