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.
I can think of 3 ways to quit an IEx shell:
- The mentioned
<ctrl-c>
hit twice or once followed byq
and then<enter>
, <ctrl-g>
and thenq
+<enter>
,- 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 other methods.
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).
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 theq
(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
(seeiex --help
and IEx -- Remote Shells).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 callSystem.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 callinghalt(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.
Looks like
System.halt
also works.
I always thought ctrl-G followed by q for quit was the official way to exit the iex shell.
See the IEx docs' section on the BREAK menu, which also shows how you can switch between alternate shells etc.
q
on the specified page. Just a short note that the BREAK menu may be used to quit. But the menu itself also does not contain the (q)uit
option, so this look completely undocumented for now. –
Jeminah © 2022 - 2024 — McMap. All rights reserved.
:init.stop
which gracefully stops the erlang VM. – Gounod