Han Ngo tieubao

Count the number of unique characters in a file

# https://unix.stackexchange.com/questions/5010/how-can-i-count-the-number-of-different-characters-in-a-file
# works for linux. There is a variation for MacOS in the link ^
sed 's/\(.\)/\1\n/g' text.txt | sort | uniq -c # sort -nr # uncomment this to sort the list by frequency

Replace a string in all instances of files in a directory

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

Must have Dockerfile inside project, that able to run docker built -t test:1.0.0 ./
Image must be expose port as 80
Image after build could run directly without any config file, config only accept to inject by environment variables

docker run -e "MYSQL_HOST=127.0.0.1" -e "MYSQL_USERNAME=root" test:1.0.0

Must have Jenkins file follow this pattern

pipeline {
    agent any

Important: I'm writing this when the last version of macOS (and the one I have installed) is Mojave. There is already a script which installs Mojave in a virtual machine here https://github.com/img2tab/okiomov. But if you are curios how to do everything manually to install High Sierra, then this guide may be useful.

After reading a few articles I ended up with these steps:

On macOS, download the High Sierra installer (even if you have Mojave installed): https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
If the High Sierra Installer starts, quit it.
Open "Disk Utility".
Click on "File" > "New Image" > "Blank image...". Or just press cmd+N.

Concurrency in Swift: One approach

Author: Chris Lattner

I'd never heard of HackerRank, but after you wrote two other employers sent me their own HackerRank tests. Having worked on those tests first (I considered them practice, for the real thing with ABC :), I'd like to check if you have flexibility in finding an alternative way to evaluate my basic coding chops.

This is because, as functional programmer and author Paul Chiusano says, "Programming is all about managing complexity" [1], but HackerRank is quite bad at measuring my ability to manage complexity. It asks for small algorithmic coding puzzles to be done in unnatural conditions including (1) time limits, (2) forbidding research on Wikipedia or StackOverflow, (3) forbidding collaboration, and (4) forbidding the use of libraries (Python and JavaScript e.g. are so different when confined to thei

	#!/bin/bash

	#shows traffic on the specified device

	function human_readable {
	VALUE=$1
	BIGGIFIERS=( B K M G )
	CURRENT_BIGGIFIER=0
	while [ $VALUE -gt 10000 ] ;do
	VALUE=$(($VALUE/1000))

	##TCP FLAGS##

	Unskilled Attackers Pester Real Security Folks
	==============================================
	TCPDUMP FLAGS
	Unskilled = URG = (Not Displayed in Flag Field, Displayed elsewhere)
	Attackers = ACK = (Not Displayed in Flag Field, Displayed elsewhere)
	Pester = PSH = [P] (Push Data)
	Real = RST = [R] (Reset Connection)
	Security = SYN = [S] (Start Connection)

	const MY_DOMAIN = "agodrich.com"
	const START_PAGE = "https://www.notion.so/gatsby-starter-notion-2c5e3d685aa341088d4cd8daca52fcc2"
	const DISQUS_SHORTNAME = "agodrich"

	addEventListener('fetch', event => {
	event.respondWith(fetchAndApply(event.request))
	})

	const corsHeaders = {
	"Access-Control-Allow-Origin": "*",

	Latency Comparison Numbers
	--------------------------
	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