Joshua Hansen joshes

CSV SQLite

Source: https://til.simonwillison.net/sqlite/one-line-csv-operations

sqlite3 \
  :memory: \
  -cmd '.mode csv' \
  -cmd '.import taxi.csv taxi' \
 'SELECT passenger_count, COUNT(*), AVG(total_amount) FROM taxi GROUP BY passenger_count'

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

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

AWS CLI Cheatsheet

http://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html https://www.youtube.com/watch?v=_wiGpBQGCjU

	#!/usr/bin/env bash

	# Print all Airflow URLs you have access to with their environment name
	for env in $(aws mwaa list-environments \| jq -r '.Environments[]'); do
	echo "Env: $env - url: https://$(aws mwaa get-environment --name $env \| jq -r '.Environment.WebserverUrl')"
	done

	# Pass the env-vars to MYCOMMAND
	eval $(egrep -v '^#' .env \| xargs) MYCOMMAND
	# … or ...
	# Export the vars in .env into your shell:
	export $(egrep -v '^#' .env \| xargs)

	#!/bin/bash
	###
	### my-script — does one thing well
	###
	### Usage:
	### my-script <input> <output>
	###
	### Options:
	### <input> Input file to read.
	### <output> Output file to write. Use '-' for stdout.

	# https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/mon-scripts.html
	#.ebextensions/01-memorymon.config

	packages:
	yum:
	perl-Switch: []
	perl-DateTime: []
	perl-Sys-Syslog: []
	perl-LWP-Protocol-https: []
	perl-Digest-SHA.x86_64: []

	# Show stats
	sudo du -d1 -h /var/lib/docker \| sort -h

	# Cleanup images
	sudo docker rmi $(sudo docker images --filter "dangling=true" -q --no-trunc)

	# Cleanup volumes
	sudo docker ps -a \| awk 'NR>1 {print $1}' \| xargs sudo docker rm
	sudo docker volume rm $(sudo docker volume ls -qf dangling=true)

Joshua Hansen joshes

CSV SQLite

Latency numbers every programmer should know

Python 2.x

AWS CLI Cheatsheet

Setup