Exec : display stdout "live"
coffeescript, javascript, node.js
Solution
Don't use `exec`. Use `spawn` which is an `EventEmmiter` object. Then you can listen to `stdout`/`stderr` events (`spawn.stdout.on('data',callback..)`) as they happen.
From NodeJS documentation:
var spawn = require('child_process').spawn,
ls = spawn('ls', ['-lh', '/usr']);
ls.stdout.on('data', function (data) {
console.log('stdout: ' + data.toString());
});
ls.stderr.on('data', function (data) {
console.log('stderr: ' + data.toString());
});
ls.on('exit', function (code) {
console.log('child process exited with code ' + code.toString());
});
`exec` buffers the output and usually returns it when the command has finished executing.
Problem
I have this simple script : ``` var exec = require('child_process').exec; exec('coffee -cw my_file.coffee', function(error, stdout, stderr) { console.log(stdout); }); ``` where I simply execute a command to compile a coffee-script file. But stdout never get displayed in the console, because the command never ends (because of the -w option of coffee). If I execute the command directly from the console I get message like this : ``` 18:05:59 - compiled my_file.coffee ``` My question is : is it possible to display these messages with the node.js exec ? If yes how ? !