javascript - How to pipe Node.js scripts together using the Unix | pipe (on the command line)? -

i see how pipe stuff using node.js streams, how pipe multiple scripts using unix |, given of these scripts can async?

$ ./a.js | ./b.js 

example:

a.js (chmod 0755)

#!/usr/bin/env node  settimeout(function(){   console.log(json.stringify({ foo: 'bar' })); }, 10); 

b.js (chmod 0755)

#!/usr/bin/env node  console.log(process.argv); 

this output:

$ ./a.js | ./b.js [ 'node', '/users/viatropos/tests/b.js' ]  events.js:72         throw er; // unhandled 'error' event               ^ error: write epipe     @ errnoexception (net.js:883:11)     @ object.afterwrite (net.js:700:19) 

at first glance seems there's lot going wrong, not sure start. there way work? end goal able take console.log output ./a.js , use in ./b.js. reason is, of time these scripts run 1 @ time, nice able pipe them together, ideally system should able handle both cases.

the problem b.js ends , closes standard in, causes error in a.js, because standard out got shut off , didn't handle possibility. have 2 options: handle stdout closing in a.js or accept input in b.js.

fixing a.js:

process.on("sigpipe", process.exit); 

if add line, it'll give when there's no 1 reading output anymore. there better things on sigpipe depending on program doing, key stop console.loging.

fixing b.js:

#!/usr/bin/env node  var stdin = process.openstdin();  var data = "";  stdin.on('data', function(chunk) {   data += chunk; });  stdin.on('end', function() {   console.log("data:\n" + data + "\nend data"); }); 

of course, don't have data. key have keeps process running; if you're piping it, stdin.on('data', fx) seems useful thing do.

remember, either 1 of prevent error. expect second useful if you're planning on piping between programs.