Roger J. Wendell
Defending 3.8 Billion Years of Organic EvolutionSM


Perl Logo Perl:
  • Practical Extraction and Reporting Language
  • Perl is a general-purpose programming language that was developed by Larry Wall. First released in 1987, Perl was originally developed for text manipulation but is now used for wide range of tasks. Perl has become a popular language for writing CGI scripts and is easy to use for building and testing simple programs...



"Perl is the Swiss Army chainsaw of scripting languages: powerful and adaptable."
(From O'Reilly's Beginner's Introduction to Perl)


Arrow Pointing Right Click Here for my main computer page...
Arrow Pointing Right Click Here for my UNIX page...


"I programmed for the most part in the first year or so in Perl; and Craigslist, these days, it's pretty much all Perl."
- Craig Newmark, founder of Craigslist
(in a July 2008 interview by Timothy M. O'Brien at the Personal Democracy Forum in New York)


Wirth's Law:    "Software is getting slower more rapidly than hardware becomes faster."




Y = CX^2 + B
Perl Parabola 12-25-2007
pico parabola.pl
perl parabola.pl -2 3
cat parabola.data
plot "parabola.data"
# experimenting with a parabola 12-25-2007
# c is the concavity of the parabola
# Y = CX^2 + B
# B is the intercept with the Y axis
# ARGV is argument variable containing the arguments
# to the program on the command line
$c = $ARGV[0]; $b = $ARGV[1]; open (filehandle, ">parabola.data");
for ( $x = -10; $x<=10; $x=$x+.1 )
       $y = $c * $x * $x + $b;
       print filehandle $x, " ", $y, "\n";
close (filehandle);




Perl Camel Basics

Under UNIX, Perl acts like a shell interpreter.
Most UNIX systems store Perl in /usr/bin/perl


In Perl, numbers and strings are the basic unit of conversation and are called scalars. Scalars that represent information that does not change over the life of the program are called constants or literals. Examples of literals are pi (3.14159265...), the name of the fourth planet from the sun (Mars), or the absolute limit of causal interation (299,792,458 metres per second [1,079,252,849 km/h]).

In Perl, scalars that change are called scalar variables. You can change the contents of a variable because they merely act as as handles for the data they represent. Variable are usually given convenient and easy-to-remember names that allow you to easily refer to the data you are manipulating.


Perl Camel - Small Perl Operators


Perl Camel - Small Simple bits of Code:

Hello, world!
   print "Hello, world!\n"; 



Current Time
# file: time.pl
  $time = localtime;
  print "The time is now $time\n";



A Simple Calculator

while(<STDIN>) {
    $i = $_; chomp($i); unless($i) { last }
    $o = eval($i); print "Answer = $o\n";






Perl Camel - Small Perl References and Related Stuff:




A Really Bad Computer Day This site best viewed with a Computer and a Monitor!



  1. 0Spam (Zero Spam)
  2. Annoyances Fixing problems with Microsoft Windows
  3. Anti-Phishing
  4. Arachnophilia - the Paul Lutus CareWare page
  5. Avast - free Anti-Virus
  6. AVG Anti-Virus
  7. Bitmek "Let the power of the Internet work for you!"
  8. Bug Me Not - Avoid Internet registrations
  9. Button generator
  10. Button maker by Cool Archive
  11. Central Ops - Free online network utilities
  12. CGI Scripts
  13. Colors in HTML - 16 million of 'em!
  14. Computer History Museum
  15. Computer Stuff - by me!
  16. CrackSpider
  17. Debian - free operating system
  18. Dillo - speedy, small footprint web browser (free!)
  19. DMOZ - Open Directory Project
  20. Drupal
  21. Entity References
  22. Eprompter Free Email Retrieval and Notification
  23. Flaming Text
  24. Foxit - Free pdf viewer
  25. Ghostscript, Gohstview, and GSview
  26. GNOME Project - Free desktop environment
  27. GNU Project - Free Unix-like operating system
  28. HTML Character Reference
  29. HTML Character Set by Walter Ian Kaye
  30. HTML Ordered Lists
  31. Infinite Monkeys Eclectic Software
  32. JavaScript Source - "...an excellent JavaScript resource"
  33. K7 Net Unified Messaging
  34. Keir.net - Robin Keir's software utilites page
  35. Kephyr - Nice software for nice people
  36. Launchpad - services for projects in the open source universe
  37. Libre Office - free office software by the Document Foundation
  1. McAfee Stinger Virus Removal
  2. Memory Hole Resucing knowledge, freeing information
  3. Mozilla Foxfire webrowswer (free!)
  4. Nyx - Spirit of the Night (free Unix shell accounts)
  5. Old Version - Because newer is not always better
  6. Open Office
  7. Open Source Initiative
  8. PC Hell
  9. PC Pitstop free automated tests...
  10. Perl - by me!
  11. Perl - The source for Perl
  12. Perl Directory
  13. Pic Search
  14. PGP by me!
  15. Protonic "free fast technical support"
  16. Python programming language
  17. Raspberry Pi - tiny and affordable computers...
  18. RoundCube - open source webmail software
  19. SDF - Super Dimension Fortress (a networked community of free software authors...)
  20. Save This
  21. Softpedia The encyclopedia of free software downloads!
  22. Source Forge - Find and Develop Open Source Software
  23. Special Alt Characters
  24. Spell Checker (Online)
  25. SpyBot Search and Destroy!
  26. TechDirt - government policy, technology and legal issues
  27. Test Page that allows me to test stuff!
  28. Toast Net Connection Performance Test
  29. Unicode Consortium
  30. Ubuntu - UNIX for Humans!
  31. Unix, Linux, and Raspberry Pi - by me!
  32. Validome HTML / XHTML / WML / XML Validator
  33. VideoLAN - a great media player!
  34. W3 World Wide Web Consortium
  35. Wayback Machine - Internet Archive
  36. What's My DNS? - DNS Server Testing Tool
  37. ZamZar - Free online File Conversion




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