const childProcess = require('child_process');

let maxExec = 5;

function execProcess(command) { // Запуск внешней команды
    childProcess.exec(command, function(error, stdout, stderr) {
        //console.log('stdout: ' + stdout);
        //console.log('stderr: ' + stderr);
        if (error !== null) {
            console.log('error: ' + error);
        }
    })
}

currentCountProc = execProcess('ps aux | grep -c web.js');

if (currentCountProc < maxExec + 1) {
    for (let i = 0; i < maxExec - currentCountProc; i++) {
        execProcess('node ./web.js');
    }
}