James Hudon hudon

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

Stores data elements based on an sequential, most commonly 0 based, index.
Based on tuples from set theory.

Keybase proof

I hereby claim:

I am hudon on github.
I am hudon (https://keybase.io/hudon) on keybase.
I have a public key whose fingerprint is CCF4 66F0 9D45 FFFA E97D 59E2 9C99 4054 9B44 7CFC

To claim this, I am signing this object:

	byteSum :: [Word8] -> [Word8] -> [Word8]
	byteSum = byteSum' 0
	where
	byteSum' 0 [] [] = []
	byteSum' 1 [] [] = [1]
	byteSum' carry (x:xs) (y:ys) =
	let v = x + y + carry
	in v : byteSum' (if v < x \|\| v < y then 1 else 0) xs ys

	# /bin
	#gists.txt
	#https://github.com/gist/hudon/0ccd3601425b25b5e559
	#https://github.com/gist/hudon/89254003f8d5491a2e1d
	# ...
	#
	while read -r in
	do
	url=${in/gist\/andy/gist}.git
	url=${url/https:\/\/github.cbhq.net/git@github.cbhq.net:}

	# decrypt /path/to/decrypted/target
	# assumes existence of target.iv, target.key (aes-256-cbc), target.enc (encrypted target)
	decrypt () {
	local IV=`base64 -d < "$1.iv" \| openssl rsautl -decrypt \
	-inkey /etc/ssl/private/private.key`
	local KEY=`base64 -d < "$1.key" \| openssl rsautl -decrypt \
	-inkey /etc/ssl/private/private.key`
	openssl aes-256-cbc -d -a -in "$1.enc" -out "$1" -iv "$IV" -K "$KEY"
	}

	def self.encrypt(data, crt_pem)
	cert = OpenSSL::X509::Certificate.new(crt_pem)
	rsa = cert.public_key

	aes = OpenSSL::Cipher::Cipher.new('aes-256-cbc')
	aes.encrypt
	key = aes.random_key.unpack('H*')[0]
	iv = aes.random_iv.unpack('H*')[0]

	ciphertext = aes.update(data)

	#!/bin/bash

	# Docker can't pass newlines to containers if there are \n in variables in
	# --env-file files. This tool creates a $1.exported file with newlines that
	# can be sourced before running your container and a $1.vars for you to pass
	# to --env-files so docker passes those variables to the container.

	# Usage:
	# dockerize-env .env
	# This creates: .env.vars and .env.exported

	#!/bin/bash
	find . \| grep 'MacBook' \| while read -r line ; do ; mv "$line" $(echo "$line" \| sed 's/ (Ja.MacBook.17)//') ; done

	cat > /var/tmp/log-truncate <<EOF
	#!/bin/sh
	set -eux
	cd /var/lib/docker/containers
	for id in *
	do
	logfile="\${id}/\${id}-json.log"
	[ -e "\${logfile}" ] && truncate -s 0 "\${logfile}"
	done
	btrfs balance start -v -dusage=20 /var/lib/docker/btrfs