[erlang-questions] remsh

[Jon Watte]

Why wouldn't an rpc that does an eval() of erlang "shell" code input work?
Seems easier than faking window-system-specific keycodes...

Sincerely,

jw


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On Fri, Jul 15, 2011 at 11:30 AM, Vincent de Phily <
vincent.dephily@REDACTED> wrote:

> On Wednesday 13 July 2011 18:23:41 Jon Watte wrote:
> > If I understand it correctly, "remsh" specifies to create an interactive
> > shell conneted to the remote node, but a command-line argument is
> evaluated
> > using the local node.
> > Try evaluating it as a rpc:call expression instead? You won't need a
> -remsh
> > at all then, instead passing the node argument to the rpc call.
>
> That's how I understand it too, and it's really annoying that you can only
> use
> remsh interactively.
>
> rpc:call/4 is fine, but it only works one call at a time, needs to send all
> the results over the wire, and becomes useless as soon as you use terms
> that
> are tied to the VM.
>
> I've tried all maners of techniques to send input to a remsh: -eval,
> -noshell,
> -oldshell, -noinput, using a pipe, echoing in /proc/$PID/fd/0... The only
> thing that works is a hack with X that simulates keyboard input.
>
> Another thing that works is
> erl -noinput -name foobar@REDACTED \
>    -eval "try {ok,S,_} = erl_scan:string(\"$YOURCODEHERE\"),
>               {ok,P} = erl_parse:parse_exprs(S),
>               {value,V,_} = rpc:call('$NODE', erl_eval, exprs, [P,[]]),
>               io:format(\"\\e[32mok\\e[m\n~p\n\", [V])
>           catch
>               _:Err -> io:format(\"\\e[31merror\\e[m\n~p\n\", [Err])
>           end." \
>    -s erlang halt
> but it isn't much more elegant.
>
>
> So I've got some nontrivial code to run remotely and automatically, but for
> various reasons I do not want to have a module loaded on the remote node
> that
> does the work. Most languages with an interactive shell will happily read
> from
> standard input instead of from the tty, but /usr/bin/erl doesn't. It has
> -eval
> which is great, except that it doesn't work with a remote shell. Any idea ?
> --
> Vincent de Phily
>
>
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