var log4node = require('log4node'),
    log = new log4node.Log4Node({level: 'warning', file: 'test.log'});

log.setPrefix("%l %p : ");

var sublogger1 = log.clone({prefix: "SUB1 - "});
var sublogger2 = log.clone({prefix: "SUB2 - ", level: 'error'});

sublogger1.warning("titi1");

setTimeout(function() {
  sublogger2.critical("titi2");
  sublogger2.warning("titi3");
}, 500);

sublogger1.warning("titi4");