stop and run again an application in erlang

Question

have an application developed in Erlang and to run this application I need to do: ./build.sh && ./deploy.sh && ./erl_start.sh

I want to make a function that will do the same thing as Ctrl + C and run ./build.sh && ./deploy.sh && ./erl_start.sh

meaning stop the application and run again this application

I try with this function :

verify(Val)->
    if Val =:=40 ->
Pid = self(), 

io:format("~w~n",[Pid]),
spawn(fun() -> exit(Pid, kill) end),
    LsOut = os:cmd("./build.sh && ./deploy.sh && ./erl_start.sh");

    true -> ok

    end.

and when I test this function I have this error :

1> model:verify(40).
<0.144.0>
** exception exit: killed

I test this command :

1> [io:format("~p : ~p~n",[Pid,erlang:process_info(Pid,current_function)]) || Pid <- processes()].
<0.0.0> : {current_function,{init,loop,1}}
<0.3.0> : {current_function,{erl_prim_loader,loop,3}}
<0.5.0> : {current_function,{gen_event,fetch_msg,5}}
<0.6.0> : {current_function,{gen_server,loop,6}}
<0.8.0> : {current_function,{application_master,main_loop,2}}
<0.9.0> : {current_function,{application_master,loop_it,4}}
<0.10.0> : {current_function,{gen_server,loop,6}}
<0.11.0> : {current_function,{gen_server,loop,6}}
<0.12.0> : {current_function,{gen_server,loop,6}}
<0.13.0> : {current_function,{global,loop_the_locker,1}}
<0.14.0> : {current_function,{global,collect_deletions,2}}
<0.15.0> : {current_function,{global,loop_the_registrar,0}}
<0.16.0> : {current_function,{gen_server,loop,6}}
<0.18.0> : {current_function,{gen_server,loop,6}}
<0.19.0> : {current_function,{gen_server,loop,6}}
<0.20.0> : {current_function,{code_server,loop,1}}
<0.21.0> : {current_function,{gen_server,loop,6}}
<0.22.0> : {current_function,{standard_error,server_loop,1}}
<0.23.0> : {current_function,{gen_server,loop,6}}
<0.24.0> : {current_function,{user_drv,server_loop,5}}
<0.25.0> : {current_function,{group,server_loop,3}}
<0.26.0> : {current_function,{group,server_loop,3}}
<0.27.0> : {current_function,{shell,shell_rep,4}}
<0.28.0> : {current_function,{gen_server,loop,6}}
<0.29.0> : {current_function,{gen_server,loop,6}}
<0.36.0> : {current_function,{application_master,main_loop,2}}
<0.37.0> : {current_function,{application_master,loop_it,4}}
<0.38.0> : {current_function,{gen_server,loop,6}}
<0.39.0> : {current_function,{gen_event,fetch_msg,5}}
<0.40.0> : {current_function,{gen_server,loop,6}}
<0.41.0> : {current_function,{gen_server,loop,6}}
<0.44.0> : {current_function,{gen_server,loop,6}}
<0.45.0> : {current_function,{mnesia_locker,loop,1}}
<0.46.0> : {current_function,{gen_server,loop,6}}
<0.47.0> : {current_function,{mnesia_tm,doit_loop,1}}
<0.48.0> : {current_function,{gen_server,loop,6}}
<0.49.0> : {current_function,{gen_server,loop,6}}
<0.53.0> : {current_function,{gen_server,loop,6}}
<0.54.0> : {current_function,{gen_server,loop,6}}
<0.63.0> : {current_function,{disk_log,loop,1}}
<0.65.0> : {current_function,{gen_server,loop,6}}
<0.66.0> : {current_function,{gen_server,loop,6}}
<0.67.0> : {current_function,{gen_server,loop,6}}
<0.68.0> : {current_function,{gen_server,loop,6}}
<0.69.0> : {current_function,{mnesia_late_loader,loop,1}}
<0.105.0> : {current_function,{application_master,main_loop,2}}
<0.106.0> : {current_function,{application_master,loop_it,4}}
<0.107.0> : {current_function,{gen_server,loop,6}}
<0.108.0> : {current_function,{gen_server,loop,6}}
<0.109.0> : {current_function,{gen_server,loop,6}}
<0.110.0> : {current_function,{gen_server,loop,6}}
<0.111.0> : {current_function,{gen_server,loop,6}}
<0.112.0> : {current_function,{gen_server,loop,6}}
<0.113.0> : {current_function,{gen_server,loop,6}}
<0.114.0> : {current_function,{gen_server,loop,6}}
<0.115.0> : {current_function,{gen_server,loop,6}}
<0.117.0> : {current_function,{gen_server,loop,6}}
<0.118.0> : {current_function,{gen_server,loop,6}}
<0.119.0> : {current_function,{gen_server,loop,6}}
<0.120.0> : {current_function,{gen_server,loop,6}}
<0.121.0> : {current_function,{prim_inet,accept0,2}}
<0.123.0> : {current_function,{gen_server,loop,6}}
<0.124.0> : {current_function,{gen_server,loop,6}}
<0.125.0> : {current_function,{gen_server,loop,6}}
<0.126.0> : {current_function,{gen_server,loop,6}}
<0.127.0> : {current_function,{prim_inet,accept0,2}}
<0.129.0> : {current_function,{gen_server,loop,6}}
<0.130.0> : {current_function,{gen_server,loop,6}}
<0.131.0> : {current_function,{gen_server,loop,6}}
<0.132.0> : {current_function,{gen_server,loop,6}}
<0.133.0> : {current_function,{prim_inet,accept0,2}}
<0.135.0> : {current_function,{gen_server,loop,6}}
<0.136.0> : {current_function,{gen_server,loop,6}}
<0.137.0> : {current_function,{gen_server,loop,6}}
<0.138.0> : {current_function,{gen_server,loop,6}}
<0.139.0> : {current_function,{prim_inet,accept0,2}}
<0.140.0> : {current_function,{gen_server,loop,6}}
<0.143.0> : {current_function,{os,start_port_srv_loop,2}}
<0.144.0> : {current_function,{erl_eval,do_apply,5}}
[ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,
 ok,ok,ok,ok,ok,ok,ok,ok,ok,ok|...]

and also I test this command :

1> [io:format("~p : ~p~n",[Pid,erlang:process_info(Pid,initial_call)]) || Pid <- processes()]. 
<0.0.0> : {initial_call,{otp_ring0,start,2}}
<0.3.0> : {initial_call,{erlang,apply,2}}
<0.5.0> : {initial_call,{proc_lib,init_p,5}}
<0.6.0> : {initial_call,{erlang,apply,2}}
<0.8.0> : {initial_call,{proc_lib,init_p,5}}
<0.9.0> : {initial_call,{application_master,start_it,4}}
<0.10.0> : {initial_call,{proc_lib,init_p,5}}
<0.11.0> : {initial_call,{proc_lib,init_p,5}}
<0.12.0> : {initial_call,{proc_lib,init_p,5}}
<0.13.0> : {initial_call,{erlang,apply,2}}
<0.14.0> : {initial_call,{erlang,apply,2}}
<0.15.0> : {initial_call,{erlang,apply,2}}
<0.16.0> : {initial_call,{proc_lib,init_p,5}}
<0.18.0> : {initial_call,{proc_lib,init_p,5}}
<0.19.0> : {initial_call,{proc_lib,init_p,5}}
<0.20.0> : {initial_call,{erlang,apply,2}}
<0.21.0> : {initial_call,{proc_lib,init_p,5}}
<0.22.0> : {initial_call,{standard_error,server,2}}
<0.23.0> : {initial_call,{proc_lib,init_p,5}}
<0.24.0> : {initial_call,{user_drv,server,2}}
<0.25.0> : {initial_call,{group,server,3}}
<0.26.0> : {initial_call,{group,server,3}}
<0.27.0> : {initial_call,{erlang,apply,2}}
<0.28.0> : {initial_call,{proc_lib,init_p,5}}
<0.29.0> : {initial_call,{proc_lib,init_p,5}}
<0.36.0> : {initial_call,{proc_lib,init_p,5}}
<0.37.0> : {initial_call,{application_master,start_it,4}}
<0.38.0> : {initial_call,{proc_lib,init_p,5}}
<0.39.0> : {initial_call,{proc_lib,init_p,5}}
<0.40.0> : {initial_call,{proc_lib,init_p,5}}
<0.41.0> : {initial_call,{proc_lib,init_p,5}}
<0.44.0> : {initial_call,{proc_lib,init_p,5}}
<0.45.0> : {initial_call,{proc_lib,init_p,5}}
<0.46.0> : {initial_call,{proc_lib,init_p,5}}
<0.47.0> : {initial_call,{proc_lib,init_p,5}}
<0.48.0> : {initial_call,{proc_lib,init_p,5}}
<0.49.0> : {initial_call,{proc_lib,init_p,5}}
<0.53.0> : {initial_call,{proc_lib,init_p,5}}
<0.54.0> : {initial_call,{proc_lib,init_p,5}}
<0.63.0> : {initial_call,{proc_lib,init_p,5}}
<0.65.0> : {initial_call,{proc_lib,init_p,5}}
<0.66.0> : {initial_call,{proc_lib,init_p,5}}
<0.67.0> : {initial_call,{proc_lib,init_p,5}}
<0.68.0> : {initial_call,{proc_lib,init_p,5}}
<0.69.0> : {initial_call,{proc_lib,init_p,5}}
<0.105.0> : {initial_call,{proc_lib,init_p,5}}
<0.106.0> : {initial_call,{application_master,start_it,4}}
<0.107.0> : {initial_call,{proc_lib,init_p,5}}
<0.108.0> : {initial_call,{proc_lib,init_p,5}}
<0.109.0> : {initial_call,{proc_lib,init_p,5}}
<0.110.0> : {initial_call,{proc_lib,init_p,5}}
<0.111.0> : {initial_call,{proc_lib,init_p,5}}
<0.112.0> : {initial_call,{proc_lib,init_p,5}}
<0.113.0> : {initial_call,{proc_lib,init_p,5}}
<0.114.0> : {initial_call,{proc_lib,init_p,5}}
<0.115.0> : {initial_call,{proc_lib,init_p,5}}
<0.117.0> : {initial_call,{proc_lib,init_p,5}}
<0.118.0> : {initial_call,{proc_lib,init_p,5}}
<0.119.0> : {initial_call,{proc_lib,init_p,5}}
<0.120.0> : {initial_call,{proc_lib,init_p,5}}
<0.121.0> : {initial_call,{proc_lib,init_p,5}}
<0.123.0> : {initial_call,{proc_lib,init_p,5}}
<0.124.0> : {initial_call,{proc_lib,init_p,5}}
<0.125.0> : {initial_call,{proc_lib,init_p,5}}
<0.126.0> : {initial_call,{proc_lib,init_p,5}}
<0.127.0> : {initial_call,{proc_lib,init_p,5}}
<0.129.0> : {initial_call,{proc_lib,init_p,5}}
<0.130.0> : {initial_call,{proc_lib,init_p,5}}
<0.131.0> : {initial_call,{proc_lib,init_p,5}}
<0.132.0> : {initial_call,{proc_lib,init_p,5}}
<0.133.0> : {initial_call,{proc_lib,init_p,5}}
<0.135.0> : {initial_call,{proc_lib,init_p,5}}
<0.136.0> : {initial_call,{proc_lib,init_p,5}}
<0.137.0> : {initial_call,{proc_lib,init_p,5}}
<0.138.0> : {initial_call,{proc_lib,init_p,5}}
<0.139.0> : {initial_call,{proc_lib,init_p,5}}
<0.140.0> : {initial_call,{proc_lib,init_p,5}}
<0.143.0> : {initial_call,{erlang,apply,2}}
<0.144.0> : {initial_call,{erlang,apply,2}}
[ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,ok,
 ok,ok,ok,ok,ok,ok,ok,ok,ok,ok|...]

I try with this function :

verify(Val) ->
    erlang:halt();

verify(_) ->
    % do nothing

   ok.

and when I test I have this result :

1>  model:verify(40).
root@ubuntu:/home/afif/Desktop/ttest/erlang# 

it only exit the VM

but as I already said I want to stop the application and run again this application

and for this I try with :

verify(Val) ->
        erlang:halt(),
    LsOut = os:cmd("./build.sh && ./deploy.sh && ./erl_start.sh");
    verify(_) ->
        % do nothing

       ok.

but I have the same result like the previous code

what I've done is half of work remains how to run the program again

Answer 1

If you only want to exit the VM in order to restart, you can use the function erlang:halt() or erlang:halt(Status). From the documentation:

halt()

Halts the Erlang runtime system and indicates normal exit to the calling environment. Has no return value.

halt().

os_prompt%

halt(Status)

Types:

Status = integer() >= 0 | string()

Status must be a non-negative integer, or a string. Halts the Erlang runtime system. Has no return value. If Status is an integer, it is returned as an exit status of Erlang to the calling environment. If Status is a string, produces an Erlang crash dump with String as slogan, and then exits with a non-zero status code.

Note that on many platforms, only the status codes 0-255 are supported by the operating system.

so your code could be:

verify(40) ->
    erlang:halt();
verify(_) ->
    % do nothing
    ok.

But as I told you in your previous question, I don't think that you are looking in the good direction.