Carlos Marin carlosmarin

Here are several different ways to test a TCP port without telnet.

BASH (man page)

$ cat < /dev/tcp/127.0.0.1/22
SSH-2.0-OpenSSH_5.3
^C

$ cat &lt; /dev/tcp/127.0.0.1/23

A Few Useful Things to Know about Machine Learning

The paper presents some key lessons and "folk wisdom" that machine learning researchers and practitioners have learnt from experience and which are hard to find in textbooks.

1. Learning = Representation + Evaluation + Optimization

All machine learning algorithms have three components:

Representation for a learner is the set if classifiers/functions that can be possibly learnt. This set is called hypothesis space. If a function is not in hypothesis space, it can not be learnt.
Evaluation function tells how good the machine learning model is.
Optimisation is the method to search for the most optimal learning model.

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

A curated list of AWS resources to prepare for the AWS Certifications

A curated list of awesome AWS resources you need to prepare for the all 5 AWS Certifications. This gist will include: open source repos, blogs & blogposts, ebooks, PDF, whitepapers, video courses, free lecture, slides, sample test and many other resources.

	def urlses(cl: ClassLoader): Array[java.net.URL] = cl match {
	case null => Array()
	case u: java.net.URLClassLoader => u.getURLs() ++ urlses(cl.getParent)
	case _ => urlses(cl.getParent)
	}

	val urls = urlses(getClass.getClassLoader)
	println(urls.filterNot(_.toString.contains("ivy")).mkString("\n"))

	#!/bin/bash
	#
	# Licensed to the Apache Software Foundation (ASF) under one or more
	# contributor license agreements. See the NOTICE file distributed with
	# this work for additional information regarding copyright ownership.
	# The ASF licenses this file to You under the Apache License, Version 2.0
	# (the "License"); you may not use this file except in compliance with
	# the License. You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0

	ERROR 2015-12-22 09:51:40,916 main.py:146 - Ambari agent machine hostname (ip-172-29-2-93.eu-west-1.compute.internal) does not match expected ambari server hostname (namenode1.dscluster200.prod.souq.com). Aborting registration. Please check hostname, hostname -f and /etc/hosts file to confirm your hostname is setup correctly
	ERROR 2015-12-22 09:51:40,916 main.py:315 - Fatal exception occurred:
	Traceback (most recent call last):
	File "/usr/lib/python2.6/site-packages/ambari_agent/main.py", line 312, in <module>
	main(heartbeat_stop_callback)
	File "/usr/lib/python2.6/site-packages/ambari_agent/main.py", line 265, in main
	perform_prestart_checks(expected_hostname)
	File "/usr/lib/python2.6/site-packages/ambari_agent/main.py", line 147, in perform_prestart_checks
	sys.exit(1)
	SystemExit: 1

	# LVDB - LLOOGG Memory DB
	# Copyriht (C) 2009 Salvatore Sanfilippo <[email protected]>
	# All Rights Reserved

	# TODO
	# - cron with cleanup of timedout clients, automatic dump
	# - the dump should use array startsearch to write it line by line
	# and may just use gets to read element by element and load the whole state.
	# - 'help','stopserver','saveandstopserver','save','load','reset','keys' commands.
	# - ttl with milliseconds resolution 'ttl a 1000'. Check ttl in dump!

	// Version 2.0.1
	// This script will remove all videos from watch later list
	//
	// Usage
	//
	// #1 go to https://www.youtube.com/playlist?list=WL
	// #2 run following script in your browser console
	(async function() {

	const playlistName = document.querySelector('.metadata-wrapper #container #text')?.textContent \|\| document.querySelector('#text')?.textContent