Michael Hogg - Software


	Overview

	GCE

	Marble Challenge

	ASCIIroids

	PSD (Second Life)

	Gravity Bubbles

	FractalNet

	EcoSim

	Cosmic Dust

	LandMesh

	Imagencrypter

	Foxy Detector

	MacDiff

	Asteroid Belt

	Matrix Attack

	Solar Swarm

	OS X Terminal

	Tools

	Names :-)

MacDiff

MacDiff is a file-comparison program for Mac OS X, which I wrote in about 1,400 lines of Java. It can compare two individual files, or it can recursively compare all the files in two directories (including subdirectories).

MacDiff is not a text-comparison program – it doesn’t compare two text files line by line. Instead, it compares the following items:

Sizes – The number of bytes in each file.
Modified dates – The date when each file was last modified.
Metadata – The Spotlight metadata of each file (see below).
UNIX – The UNIX filetype and access permissions of each file.
Data – The actual bytes of each file.

The program can ignore .DS_Store files (hidden files created by OS X to store custom attributes of a folder, such as the position of icons or the choice of a background image), and can write the comparison results to a text file for later inspection.

The stat OS X command line utility is used by MacDiff to obtain the UNIX filetype and access permissions for each file, and the mdls utility is used to obtain all the metadata that Spotlight has stored about each file (see this article for more information). MacDiff can be told to ignore certain metadata attributes (such as LastUsedDate) if they are causing an unhelpfully large number of file differences to be reported. Below is a list of the metadata attributes that MacDiff can compare:

General