optimist で いい感じに spawn させる例

spawn.js

var spawn = require('child_process').spawn; 
var argv = require('optimist') 
                .usage('Usage: $0 -c [num] [cmd]\nExample: $0 -c 4 ls ..') 
                .demand('c') 
                .alias('c', 'concurrency') 
                .argv; 
 
console.time(argv.$0); 
 
for (var i = 1; i <= argv.c; i++) { 
        (function(n) { 
                process.env.CHILD_ID = n; 
 
                var child = spawn(argv._[0], argv._.slice(1)); 
 
                child.stdout.setEncoding('utf8'); 
                child.stdout.on('data', function(data) { 
                        process.stdout.write(data); 
                }); 
 
                child.stderr.setEncoding('utf8'); 
                child.stderr.on('data', function(data) { 
                        process.stderr.write(data); 
                }); 
 
                child.on('exit', function(code) { 
                        console.log('exit', code); 
                }); 
        })(i); 
} 
 
process.on('exit', function () { 
        console.timeEnd(argv.$0); 
}); 
 
process.on('uncaughtException', function (err) { 
        try { 
                console.error(err); 
        } catch (e) { 
                console.log(e);
        } finally { 
                process.exit(1); 
        } 
}); 
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