I am learning Erlang/OTP, and in Chapter 14 it says:
"you can load Module to all nodes use shell command :
command nl(Mod)".
I want to know, how to do this? I can't find the shell command : command nl(Mod).
You tried to type help(). in shell? This function is defined in c module in stdlib. But shell will understand nl(Mod).
To perform test, start at least two erlang vms and connect it:
erl -pa your_module_path -name [email protected]
erl -name [email protected]
in first shell connect to second node by:
net_kernel:connect('[email protected]').
should respond with true.
In your_module_path create some simple module like:
-module(nl_test).
-export([test/0]).
test() -> 1.
and compile it by c(nl_test). Now you can run nl_test:test() from first shell but the second one can't load it. To broadcast it and force load, just run from first nl(nl_test). Now try from second shell nl_test:test().
Let's say you modified test() -> 1. to test() -> 2. and all you need to do is to just run c(nl_test), nl(nl_test). or shorter nc(nl_test) which means the same.
nl_test:test(). on all your connected nodes should return 2.
This may look very easy but in complicated production systems, proper hot-loading is quite advanced problem.