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POHow to continuously show os command output in erlang?
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copied!<p>I need continuously show stdout/stderr from os command in erlang. In ruby I can implement it with following code:</p> <pre><code>s1, s2 , s3, t = Open3.popen3('for %a in (1 2 3 4 5 6 7 8 9) do (echo message & sleep 2 ) 2>&1 ') s2.each do |l| puts l end </code></pre> <p>it will show 'message\n message\n' in 'real time' - does not wait end of process.</p> <p>I've tried <code>os:cmd(..)</code> and </p> <pre><code>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 </code></pre> <p>but both of them wait end of process.</p> <p>Are the any optional for continuously stdout reading in Erlang?</p> <p><strong>EDIT:</strong> In other words I look for a popen (c/c++; proc_open(php) and etc) function in erlang</p> <p><strong>EDIT2</strong> Code, that works on linux (tested on centos6.2). Thanks for <code>vinod</code>:</p> <pre><code>-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. </code></pre> <p>Output:</p> <pre><code>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} </code></pre>

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