Another way to exiting IEX other than ctrl-C

Question

I know we can exit the IEX console with control-C. I'm curious if there's a command to type into the console that would also do the same thing.

Answer 1

1. Disconnect from shell and stop current node. This is what you need in most cases.

   1.1. Ctrl+\ - standard method to quit the Erlang shell. See "4.4 How do I quit the Erlang shell?" in Erlang -- Getting Started.

   1.2. Ctrl+C, a, Enter - via the (a)bort command of the Break menu.

   1.3. Ctrl+C, Ctrl+C - looks like undocumented feature of the Break menu.

   1.4. Ctrl+G, q, Enter - via the q (quit erlang) commant of the User Switch menu (see Erlang -- shell -- JCL Mode).

   Note: this leaves remote node alive if you have connected to it with iex --remsh (see iex --help and IEx -- Remote Shells).

2. Shut down the node you are connected to.

   2.1. System.halt - quick and dirty shut down. The runtime system exits with status code 0 (clean exit without errors). You can also call System.halt(:abort) to abort with core dump. Same as :erlang.halt.

   2.2. :init.stop (System.stop in future versions) - clean shutdown. All applications are taken down smoothly, all code is unloaded, and all ports are closed before the system terminates by calling halt(Status).

   Note: this leaves your shell alive if you have connected to a remote shell with iex --remsh.

Notice that all these options are disabled if Erlang is started with the ignore break, +Bi, system flag: iex --erl +Bi (which can be useful, for example when running a restricted shell). See Erlang -- erl for more info.

Answer 2

I can think of 3 ways to quit an IEx shell:

1. The mentioned <ctrl-c> hit twice or once followed by q and then <enter>,
2. <ctrl-g> and then q + <enter>,
3. and finally System.halt,

but there is a difference between System.halt and the others.

Namely that System.halt "halts the Erlang runtime" and the others just "quit the shell".

When you have only one shell session running or the session is not attached to a separate runtime then both ways will produce the same result. But if you have a session connected to a separate runtime e.g. via iex --remsh (remote shell) then running System.halt in it will halt the runtime and so make both shell processes / runtimes terminate. Just quitting a shell (via method 1. or 2.) will not stop the runtime it is connected to.

Conclusion: if you connect with your shell to other runtimes then know that System.halt will halt the runtime you have connected to. If you do not want to do it use <ctrl-c>.

UPDATE: Recently I have also found out about <ctrl-\>. You can read more about it in this article:

What I didn’t know is that you can exit the shell by sending Ctrl-. The shell will exit immediately. As far as I know, it has the same effect as aborting the shell in the Break command, it doesn’t affect remote nodes and it also works outside of iex (for example, you can use to terminate your tests).