MacOS File Compare (Free)

I was looking for a visual file compare utility and stumbled onto this free one from Apple which (I believe) came with XCode.  Its' located here: /Developer/Applications/Utilities/FileMerge.app and does a very nice visual file compare.  It also lets you merge the two files together.  I've have BeyondCompare for Windows at work which works a bit better than this, but for free, this is great.  Here's a screen shot of it in action:

NSDateFormatter

This link has all of the NSDateFormatter format variables which isn't in the Objective C documentation:
http://unicode.org/reports/tr35/tr35-6.html#Date_Format_Patterns

NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init]; 

NSString *format = @"EEE, MMM d, ''yy"; 

[inputFormatter setDateFormat:format]; 

NSDate *date = [inputFormatter dateFromString:sdate]; 

[inputFormatter release];

Here's the section from the standard:  Appendix F: Date Format Patterns

A date pattern is a string of characters, where specific strings of characters are replaced with date and time data from a calendar when formatting or used to generate data for a calendar when parsing. The following are the characters used in patterns to show the appropriate formats for a given locale. The following are examples:

Pattern	Result (in a particular locale)
yyyy.MM.dd G 'at' HH:mm:ss zzz	1996.07.10 AD at 15:08:56 PDT
EEE, MMM d, ''yy	Wed, July 10, '96
h:mm a	12:08 PM
hh 'o''clock' a, zzzz	12 o'clock PM, Pacific Daylight Time
K:mm a, z	0:00 PM, PST
yyyyy.MMMM.dd GGG hh:mm aaa	01996.July.10 AD 12:08 PM

Characters may be used multiple times. For example, if y is used for the year, 'yy' might produce '99', whereas 'yyyy' produces '1999'. For most numerical fields, the number of characters specifies the field width. For example, if h is the hour, 'h' might produce '5', but 'hh' produces '05'. For some characters, the count specifies whether an abbreviated or full form should be used, but may have other choices, as given below.

Two single quotes represents a literal single quote, either inside or outside single quotes. Text within single quotes is not interpreted in any way (except for two adjacent single quotes). Otherwise all ASCII letter from a to z and A to Z are reserved as syntax characters, and require quoting if they are to represent literal characters. In addition, certain ASCII punctuation characters may become variable in the future (eg ":" being interpreted as the time separator and '/' as a date separator, and replaced by respective locale-sensitive characters in display).

Note: the counter-intuitive use of 5 letters for the narrow form of weekdays and months is forced by backwards compatibility.

Date Field Symbol Table

Field	Sym.	No.	Example	Description
era	G	1..3	AD	Era - Replaced with the Era string for the current date. One to three letters for the abbreviated form, four letters for the long form, five for the narrow form.
		4	Anno Domini
		5	A
year	y	1..n	1996	Year. Normally the length specifies the padding, but for two letters it also specifies the maximum length. Example: Year y yy yyy yyyy yyyyy AD 1 1 01 001 0001 00001 AD 12 12 12 012 0012 00012 AD 123 123 23 123 0123 00123 AD 1234 1234 34 1234 1234 01234 AD 12345 12345 45 12345 12345 12345
	Y	1..n	1997	Year (of "Week of Year"), used in ISO year-week calendar. May differ from calendar year.
	u	1..n	4601	Extended year. This is a single number designating the year of this calendar system, encompassing all supra-year fields. For example, for the Julian calendar system, year numbers are positive, with an era of BCE or CE. An extended year value for the Julian calendar system assigns positive values to CE years and negative values to BCE years, with 1 BCE being year 0.
quarter	Q	1..2	02	Quarter - Use one or two for the numerical quarter, three for the abbreviation, or four for the full name.
		3	Q2
		4	2nd quarter
	q	1..2	02	Stand-Alone Quarter - Use one or two for the numerical quarter, three for the abbreviation, or four for the full name.
		3	Q2
		4	2nd quarter
month	M	1..2	09	Month - Use one or two for the numerical month, three for the abbreviation, or four for the full name, or five for the narrow name.
		3	Sept
		4	September
		5	S
	L	1..2	09	Stand-Alone Month - Use one or two for the numerical month, three for the abbreviation, or four for the full name, or 5 for the narrow name.
		3	Sept
		4	September
		5	S
week	w	1..2	27	Week of Year.
	W	1	3	Week of Month
day	d	1..2	1	Date - Day of the month
	D	1..3	345	Day of year
	F	1	2	Day of Week in Month. The example is for the 2nd Wed in July
	g	1..n	2451334	Modified Julian day. This is different from the conventional Julian day number in two regards. First, it demarcates days at local zone midnight, rather than noon GMT. Second, it is a local number; that is, it depends on the local time zone. It can be thought of as a single number that encompasses all the date-related fields.
week day	E	1..3	Tues	Day of week - Use one through three letters for the short day, or four for the full name, or five for the narrow name.
		4	Tuesday
		5	T
	e	1..2	2	Local day of week. Same as E except adds a numeric value that will depend on the local starting day of the week, using one or two letters. For this example, Monday is the first day of the week.
		3	Tues
		4	Tuesday
		5	T
	c	1	2	Stand-Alone local day of week - Use one letter for the local numeric value (same as 'e'), three for the short day, or four for the full name, or five for the narrow name.
		3	Tues
		4	Tuesday
		5	T
period	a	1	AM	AM or PM
hour	h	1..2	11	Hour [1-12].
	H	1..2	13	Hour [0-23].
	K	1..2	0	Hour [0-11].
	k	1..2	24	Hour [1-24].
minute	m	1..2	59	Minute. Use one or two for zero padding.
second	s	1..2	12	Second. Use one or two for zero padding.
	S	1..n	3457	Fractional Second - rounds to the count of letters. (example is for 12.34567)
	A	1..n	69540000	Milliseconds in day. This field behaves exactly like a composite of all time-related fields, not including the zone fields. As such, it also reflects discontinuities of those fields on DST transition days. On a day of DST onset, it will jump forward. On a day of DST cessation, it will jump backward. This reflects the fact that is must be combined with the offset field to obtain a unique local time value.
zone	z	1..3	PDT	Timezone - Use one to three letters for the short timezone or four for the full name. For more information, see Appendix J: Time Zone Display Names
		4	Pacific Daylight Time
	Z	1..3	-0800	Use one to three letters for RFC 822, four letters for GMT format.
		4	GMT-08:00
	v	1	PT	Use one letter for short wall (generic) time, four for long wall time. For more information, see Appendix J: Time Zone Display Names
		4	Pacific Time

All non-letter character represent themselves in a pattern, except for the single quote. It is used to 'escape' letters. Two single quotes in a row, whether inside or outside a quoted sequence, represent a 'real' single quote.