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Regular Expressions Cheat Sheet

(Taken from http://www.crazygrrl.com/weav/reference.php3 and modified to fit on one page, at least in Opera 8. Ow, and damn you for blogmarking this, Mathias! ;] Can't. Handle. The. Requests.)

^ The pattern has to appear at the beginning of a string. ^cat matches any string that begins with cat
$ The pattern has to appear at the end of a string. cat$ matches any string that ends with cat
. Matches any character. cat. matches catT and cat2 but not catty
[] Bracket expression. Matches one of any characters enclosed. gr[ae]y matches gray or grey
[^] Negates a bracket expression. Matches one of any characters EXCEPT those enclosed. 1[^02] matches 13 but not 10 or 12
[-] Range. Matches any characters within the range. [1-9] matches any single digit EXCEPT 0
? Preceeding item must match one or zero times. colou?r matches color or colour but not colouur
+ Preceeding item must match one or more times. be+ matches be or bee but not b
* Preceeding item must match zero or more times. be* matches b or be or beeeeeeeeee
() Parentheses. Creates a substring or item that metacharacters can be applied to a(bee)?t matches at or abeet but not abet
{n} Bound. Specifies exact number of times for the preceeding item to match. [0-9]{3} matches any three digits
{n,} Bound. Specifies minimum number of times for the preceeding item to match. [0-9]{3,} matches any three or more digits
{n,m} Bound. Specifies minimum and maximum number of times for the preceeding item to match. [0-9]{3,5} matches any three, four, or five digits
| Alternation. One of the alternatives has to match. July (first|1st|1) will match July 1st but not July 2

POSIX Character Classes

[:alnum:] alphanumeric character [[:alnum:]]{3} matches any three letters or numbers, like 7Ds
[:alpha:] alphabetic character, any case [[:alpha:]]{5} matches five alphabetic characters, any case, like aBcDe
[:blank:] space and tab [[:blank:]]{3,5} matches any three, four, or five spaces and tabs
[:digit:] digits [[:digit:]]{3,5} matches any three, four, or five digits, like 3, 05, 489
[:lower:] lowercase alphabetics [[:lower:]] matches a but not A
[:punct:] punctuation characters [[:punct:]] matches ! or . or , but not a or 3
[:space:] all whitespace characters, including newline and carriage return [[:space:]] matches any space, tab, newline, or carriage return
[:upper:] uppercase alphabetics [[:upper:]] matches A but not a

Perl-Style Metacharacters

// Default delimiters for pattern /colou?r/ matches color or colour
i Append to pattern to specify a case insensitive match /colou?r/i matches COLOR or Colour
\b A word boundary, the spot between word (\w) and non-word (\W) characters /\bfred\b/i matches Fred but not Alfred or Frederick
\B A non-word boundary /fred\B/i matches Frederick but not Fred
\d A single digit character /a\db/i matches a2b but not acb
\D A single non-digit character /a\Db/i matches aCb but not a2b
\n The newline character. (ASCII 10) /\n/ matches a newline
\r The carriage return character. (ASCII 13) /\r/ matches a carriage return
\s A single whitespace character /a\sb/ matches a b but not ab
\S A single non-whitespace character /a\Sb/ matches a2b but not a b
\t The tab character. (ASCII 9) /\t/ matches a tab.
\w A single word character - alphanumeric and underscore /\w/ matches 1 or _ but not ?
\W A single non-word character /a\Wb/i matches a!b but not a2b



Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotesSomerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose BierceBernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D


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Last modified: March 12, 2019