Question

I need to run complex Erlang module function from unix shell

rpc:call('[e-mail]', mnesia, dirty_first, [mytable])

how can i do it?

UPD:

i make test.escript

chmod +x test.escript

#!/usr/lib64/erlang/bin/escript
%%! -name '[e-mail]'
main(_Args) ->
    R = rpc:call('[e-mail]', mnesia, dirty_first, [mytable]),
    io:format("~p~n",[R]).

and receive {badrpc, nodedown}

but when run

erl -name [e-mail]
1> rpc:call('[e-mail]', mnesia, dirty_first, [mytable]).
{my, data}.

I mean it works, but howto make escript work proprely?

Answer 1

I think escript might be something worth looking into.

Edit:
Some examples.

First for all examples: Start the remote node somewhere, somehow.

            dannib@duval:~:> erl -sname bar
            (bar@duval)1> erlang:get_cookie().
            'KNKKCFPYMJUPIOLYPOAA'

Escript

1: Create a file named hello.escript with content

            #!/usr/bin/env escript
            %%! -sname foo@duval -setcookie KNKKCFPYMJUPIOLYPOAA

            main(_String) ->
                Node = 'bar@duval',
                Mod = 'erlang',
                Fun = 'node', 
                Args = [], 
                    R = rpc:call(Node, Mod, Fun, Args),
                io:format("Hello there ~p~n",[R]).

Notice that the %%! -sname foo@bar identifies the node on the host (instead of creating nonode@nohost), allow setting the same cookie %%! -sname foo@duvel -setcookie KNKKCFPYMJUPIOLYPOAA as target host which solves the problem of getting {badrpc,nodedown}. Notice that the same statement holds for the following examples (erl_call, and -eval) where both the node name and cookie is set.

2: Set the execution bit and run

            $ chmod +x hello.escript
            $ ./hello.escript 
            Hello there bar@duval

Erl_call

1: run

            $ erl_call -c 'KNKKCFPYMJUPIOLYPOAA' -a 'erlang node' -n bar@duval
            bar@duval

Eval

1: run

            $ erl -sname foo -setcookie 'KNKKCFPYMJUPIOLYPOAA' 
            -eval 'io:format("Hello there ~p~n",[rpc:call(bar@duval,erlang, node, [])])'
            ... Eshell V5.7.4  (abort with ^G)
            (foo@duval)1> Hello there bar@duval

This creates a shell which might not be what you want in this case.

I might mention that if both nodes are on the same host and using the same cookie default value, the cookie value for foo and bar don’t have to be explicitly set like in the examples.

After doing these examples and reading your question again I think what I GIVE TERRIBLE ADVICE said will be your best choice, erl_call. I fell for the word “complex” in question title where imho escripts allow much more “complex” setups in a easy-to-read manner. The variable _String in the escript example holds the arguments to the script which allows you to both access input through shell and perform complex erlang operations in the EVM. But erl_call might be more straight forward if you already have logic in some other application and just need to make this simple call to an erlang node.