perl-tutorial.pdf

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Perl Tutorial

based on a tutorial by Nano Gough

http://www.computing.dcu.ie/~ngough/perl/tutorial.ppt

Why Perl?

•

Perl is

–

Pathologically Eclectic Rubbish Lister

–

the duct tape of the internet

–

the Swiss-army chain saw of UNIX

•

good at

–

text processing

–

rapid development

–

flexibility

–

operating system stuff

•

in particular UNIX/LINUX

•

bad at

–

numeric processing

–

debugging

–

efficiency

–

code re-use

•

CPAN:large repository of re-usable modules

The Three Virtues of a Good Programmer

(not necessarily of a good Student)

•

LAZINESS:

–

The quality that makes you go to great effort to

reduce overall energy expenditure.

–

makes you want to re-use other people's code

•

IMPATIENCE:

–

The anger you feel when the computer is being lazy.

–

makes you get things done quickly (rapid prototyping)

and efficiently (optimize code)

•

HUBRIS:

–

Excessive pride.

–

makes you want to show off (code sharing) and write

(and maintain) programs that other people won't want

to say bad things about.

Running Perl



#!/usr/local/bin/perl

(tells the file to run through perl)



Use .pl extension



Perl

programName

(to run the program)



Perl -d

programName

(to run using debugger)



Perl – w

programName

(to run with warnings)

Printing

#The hash symbol (#) is use to comment lines of code

; Every statement in perl ends with a semi-colon (;)

Print “Hello World. I love perl.”;

#prints:

Hello World. I love perl.

Print “Hello World\nI love perl\n”;

#prints:

Hello World.

I love perl.

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