pwpearson

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
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

pwpearson

Check if remote port is open with bash:
echo >/dev/tcp/8.8.8.8/53 && echo "open"

Suspend process:
Ctrl + z 

Move process to foreground:
fg

Generate random hex number where n is number of characters:

pwpearson

#  ---------------------------------------------------------------------------
#
#  Description:  This file holds all my BASH configurations and aliases
#
#  Sections:
#  1.   Environment Configuration
#  2.   Make Terminal Better (remapping defaults and adding functionality)
#  3.   File and Folder Management
#  4.   Searching
#  5.   Process Management

pwpearson

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

pwpearson

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

pwpearson

val realFuture = Future(doRealStuff())
//timeoutFuture does a spin wait by sleeping on the thread on which it runs, so make sure the ExecutionContext
//on which it runs is multi-threaded. In an akka based environment, use a scheduler to fulfill a promise with a failure
//when the timeout duration is complete, and avoid the spin wait
val timeoutFuture = Future {
  Thread.sleep(timeoutMilliseconds)
  throw new TimeoutException("timeout")
}
Future.firstCompletedOf(realFuture :: timeoutFuture :: Nil)

pwpearson

scala> type Set = Int => Boolean
defined type alias Set

scala> Set
res0: scala.collection.immutable.Set.type = scala.collection.immutable.Set$@7a7f0991

scala> def contains(s: Set, elem: Int): Boolean = s(elem)
contains: (s: Int => Boolean, elem: Int)Boolean

scala> contains(x => x%2 == 0, 2)

pwpearson

// This example shows how to use row_number and rank to create
// a dataframe of precipitation values associated with a zip and date
// from the closest NOAA station
 
import org.apache.spark.sql.expressions.Window
import org.apache.spark.sql.functions._

// mocked NOAA weather station data
case class noaaData(zip:String,station:String,date:Long,value:String=null,distance:Int)
val t = Seq(

pwpearson

Keyboard shortcuts

The Spark Notebook has two different keyboard input modes. Edit mode allows you to type code/text into a cell and is indicated by a green cell border. Command mode binds the keyboard to notebook level actions and is indicated by a grey cell border.

####MacOS modifier keys

⌘: Command	⌃: Control
⌥: Option	⇧: Shift
↩: Return	␣: Space

pwpearson

#!/bin/bash
read -r -d '' script <<'EOF'
on run argv
tell application "iTerm"
    activate
    set myterm to (make new terminal)
    tell myterm
        launch session "Default"
        tell the last session
            repeat with arg in argv