operating system - How to continuously show os command output in erlang? -

i need continuously show stdout/stderr os command in erlang. in ruby can implement following code:

s1, s2 , s3, t = open3.popen3('for %a in (1 2 3 4 5 6 7 8 9) (echo message & sleep 2 ) 2>&1 ')  s2.each |l|     puts l end 

it show 'message\n message\n' in 'real time' - not wait end of process.

i've tried os:cmd(..) ,

1> p5 = erlang:open_port({spawn, "ruby rtest.rb"}, [stderr_to_stdout, in, exit_s tatus, binary,stream, {line, 255}]). #port<0.505> 2> receive {p5, data} -> io:format("data ~p~n",[data]) end. data {data,{eol,<<>>}} ok 

but both of them wait end of process.

are optional continuously stdout reading in erlang?

edit: in other words popen (c/c++; proc_open(php) , etc) function in erlang

edit2 code, works on linux (tested on centos6.2). vinod:

-module(test). -export([run/0]).   run() ->       p5 = erlang:open_port({spawn, "sh test.sh"},      [stderr_to_stdout, in, exit_status,stream, {line, 255}]),      loop(p5).  loop(p) ->        receive{p, data} ->             io:format("data ~p~n",[data]),        loop(p)        end. 

output:

10> c(test). {ok,test} 11> test:run(). data {data,{eol,"1"}} data {data,{eol,"2"}} data {data,{eol,"3"}} data {data,{eol,"4"}} data {data,{eol,"5"}} data {data,{eol,"6"}} data {data,{eol,"7"}} data {data,{eol,"8"}} data {data,{eol,"9"}} data {data,{eol,"10"}} data {exit_status,0} 

if understand correctly, want continue execute program in concurrent os command. in erlang can spawn process , can continue. example

1> spawn(fun() ->          p5 = erlang:open_port({spawn, "ruby rtest.rb"},                               [stderr_to_stdout, in, exit_status,                                binary,stream, {line, 255}]),         receive {p5, data} ->             io:format("data ~p~n",[data])         end      end). <0.32.0> 2> 5+5. 10 3> 

better write in module can understand better.