Rob Skillington robskillington

HOWTO: Using FileMerge (opendiff) with Git on OSX

FileMerge (opendiff) can really come in handy when you need to visually compare merging conflicts. Other times it's just a nice visual way to review your days work.

The following method works by creating a simple bash script (git-diff-cmd.sh) that sets us up with the proper command line arguments for Git to pass off files to FileMerge.

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

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

In August 2007 a hacker found a way to expose the PHP source code on facebook.com. He retrieved two files and then emailed them to me, and I wrote about the issue:

http://techcrunch.com/2007/08/11/facebook-source-code-leaked/

It became a big deal:

http://www.techmeme.com/070812/p1#a070812p1

The two files are index.php (the homepage) and search.php (the search page)

	#!/bin/sh
	# Amazon Linux AMI startup script for a supervisor instance
	#
	# chkconfig: 2345 80 20
	# description: Autostarts supervisord.

	# Source function library.
	. /etc/rc.d/init.d/functions

	supervisorctl="/usr/bin/supervisorctl"

	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

	#!/usr/bin/python

	# fix-xcode
	# Rob Napier <[email protected]>

	# Script to link in all your old SDKs every time you upgrade Xcode
	# Create a directory called /SDKs (or modify source_path).
	# Under it, put all the platform directories:
	# MacOSX.platform iPhoneOS.platform iPhoneSimulator.platform
	# Under those, store the SDKs:

	##########################################
	#
	# c.f. http://stackoverflow.com/questions/3520977/build-fat-static-library-device-simulator-using-xcode-and-sdk-4
	#
	# Version 2.82
	#
	# Latest Change:
	# - MORE tweaks to get the iOS 10+ and 9- working
	# - Support iOS 10+
	# - Corrected typo for iOS 1-10+ (thanks @stuikomma)

	/**
	* Several macros simplifying use of weak references to self inside blocks
	* which goal is to reduce risk of retain cycles.
	*
	* Example:
	* @code

	@interface Example : NSObject{
	int _i;
	}

	# Run this in the project repo from the command-line
	# http://stackoverflow.com/a/4593065/99923

	git log --shortstat --author "Xeoncross" --since "2 weeks ago" --until "1 week ago" \| grep "files changed" \| awk '{files+=$1; inserted+=$4; deleted+=$6} END {print "files changed", files, "lines inserted:", inserted, "lines deleted:", deleted}'