ziwon

#XLarge DBInstanceClassMemory = 15892177440 = 14.8GB
#/32 = 496630545 = 473MB
#/64 = 248315272 = 236MB
#/128 = 124157636 = 118MB
#/256 = 62078818 = 59MB
#/512 = 31039409 = 29MB
#/12582880 = 1263 #default same divisor as max_connections = 4041.6MB = 4237924762
#/25165760 = 623 # half of max_connections = 1993.6MB
#/50331520 = 315 # quarter of max_connections = 1008MB = 1056964608
#*(3/4) #default innodb pool size = 11922309120

ziwon

#!/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin:/snap/bin
log="/var/log/aws_inspector/aws_inspector_export_rep.log"
template_arn='arn:aws:inspector:us-east-1:XXXXXXXXXXXX:target/xxxxxxxxxx/template/xxxxxxxxxx'
wait_sec='5400'

log_out(){
        (($verifymon)) &&\
                echo -e "`date +'%Y-%m-%d %H:%M:%S'` (pid $$) -- $1" >> $log ||\
                echo -e "`date +'%Y-%m-%d %H:%M:%S'` (pid $$) -- $1" | tee -a $log

ziwon

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

ziwon

#!/bin/bash
# Requires: awscli (http://aws.amazon.com/cli/)
# Prints out a list of all security groups and their settings, just for quickly auditing it.

# Your AWS credentials
if [ -z ${AWS_ACCESS_KEY_ID} ]; then
    export AWS_ACCESS_KEY_ID='***'
    export AWS_SECRET_ACCESS_KEY='***'
fi

ziwon

GNU Make Cheatsheet

Based on https://www.gnu.org/software/make/manual/html_node/Quick-Reference.html

Directives

Directive	Description
define variable define variable = define variable := define variable ::= define variable += define variable ?= endef	Define multi-line variables.
undefine variable	Undefining variables.

ziwon

#!/usr/bin/env bash
####################################################################################
# Slack Bash console script for sending messages.
####################################################################################
# Installation
#    $ curl -s https://gist.githubusercontent.com/andkirby/67a774513215d7ba06384186dd441d9e/raw --output /usr/bin/slack
#    $ chmod +x /usr/bin/slack
####################################################################################
# USAGE
# Send message to slack channel/user

ziwon

sleep 5; while read -r line; do clear; echo $line; echo "$line" | pbcopy; sleep 1; done < "feed_commands_for_seoul_ap-northeast-2.txt"

ziwon

#!/bin/bash

type csvsql || brew instal csvkit
type jq || brew install jq 
type aws || brew intall awscli

TABLE_NAME=tmp
TMP_FILE=${TABLE_NAME}.csv
OUTPUT_FILE="output.csv"
truncate -s 0 "${OUTPUT_FILE}"

ziwon

#!/bin/bash

export AWS_PROFILE=default

aws ec2 describe-instances --region ap-northeast-2 \
  | jq '.Reservations[] | .Instances[] | {type: .InstanceType, tag: .Tags[] | select(.Key=="Name").Value}' \
  | jq -s '.'  \
  | jq 'sort_by(.type) | group_by(.type)[] | {
      type: .[0].type,
      name: map(.tag)} | "\( .type ): \( .name | join(", ") )"' | tr -d \" | awk -F '' '{if (NF > 110) {print substr($0, 0, 110)".."} else print $0}' \

ziwon

#!/bin/bash

region="ap-northeast-2"
all_az=()

az_per_region=$(aws ec2 describe-availability-zones --region $region --query 'AvailabilityZones[*].[ZoneName]' --output text | sort)
while read -r az; do
  all_az+=($az)
done <<< "$az_per_region"