toashd

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

toashd

# check space
df -h

# delete all non-running container
docker ps -a | grep 'Exit' |  awk '{print $1}' | xargs docker rm

# delete unused images
docker images | grep '<none>' |  awk '{print $3}'  | xargs docker rmi

# delete specific images

toashd

find <dir> -maxdepth 1 -type d -name '*foo*' -print -quit

toashd

// imageFormat returns the image format.
func imageFormat(file *os.File) string {
	bytes := make([]byte, 4)
	n, _ := file.ReadAt(bytes, 0)
	file.Seek(0, 0)
	if n < 4 {
		return ""
	}
	if bytes[0] == 0x89 && bytes[1] == 0x50 && bytes[2] == 0x4E && bytes[3] == 0x47 {
		return "png"

toashd

package main

import (
	"fmt"
	"reflect"
)

func main() {

	var i = [...]uint8{0, 7, 16, 22, 28} // array, compiler counts elements

toashd

package main

import (
	"fmt"
	"time"
)

type generator struct {
	generateNext chan struct{}
	sendCh       chan int

toashd

# Add the remote, call it "upstream":

git remote add upstream https://github.com/whoever/whatever.git

# Fetch all the branches of that remote into remote-tracking branches,
# such as upstream/master:

git fetch upstream

# Make sure that you're on your master branch:

toashd

 curl -u ':uname' 'https://api.github.com/repos/:org/:repo/issues' > issues.json

toashd

self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
self.navigationController?.navigationBar.shadowImage = UIImage()
self.navigationController?.navigationBar.translucent = true

toashd

$ brew tap homebrew/versions
$ brew install postgresql92
$ brew switch postgresql 9.2.8