Girish Duvuru girish

Client-side SSL

For excessively paranoid client authentication.

Updated Apr 5 2019:

because this is a gist from 2011 that people stumble into and maybe you should AES instead of 3DES in the year of our lord 2019.

some other notes:

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

One-line Tree in Python

Using Python's built-in defaultdict we can easily define a tree data structure:

def tree(): return defaultdict(tree)

That's it!

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

	# Ways to execute a shell script in Ruby
	# Example Script - Joseph Pecoraro

	cmd = "echo 'hi'" # Sample string that can be used

	# 1. Kernel#` - commonly called backticks - `cmd`
	# This is like many other languages, including bash, PHP, and Perl
	# Synchronous (blocking)
	# Returns the output of the shell command
	# Docs: http://ruby-doc.org/core/classes/Kernel.html#M001111

	#!/usr/bin/env ruby
	# A quick and dirty implementation of an HTTP proxy server in Ruby
	# because I did not want to install anything.
	#
	# Copyright (C) 2009-2014 Torsten Becker <[email protected]>
	#
	# Permission is hereby granted, free of charge, to any person obtaining
	# a copy of this software and associated documentation files (the
	# "Software"), to deal in the Software without restriction, including
	# without limitation the rights to use, copy, modify, merge, publish,

	import bisect

	class NFA(object):
	EPSILON = object()
	ANY = object()

	def __init__(self, start_state):
	self.transitions = {}
	self.final_states = set()
	self._start_state = start_state

	#! /usr/bin/env python
	import fileinput
	import argparse
	from operator import itemgetter

	parser = argparse.ArgumentParser()
	parser.add_argument('--target-mb', action = 'store', dest = 'target_mb', default = 61000, type = int)
	parser.add_argument('vmtouch_output_file', action = 'store', nargs = '+')
	args = parser.parse_args()

	#! /usr/bin/python

	from sys import argv
	from os.path import exists
	from os import makedirs
	from os import symlink
	from os import system
	import getopt

	#

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD