Perl

Script Examples

Using Anonymous Hash References

#!/usr/bin/perl

use strict;

my @myarray;

foreach my $iter ( 1..10 )
{
	my $value1 = "value1_".$iter;
	my $value2 = "value2_".$iter;
	my $value3 = "value3_".$iter;

   	print "Creating our \$hashref... ";
   	# Construct { key1 => value1, key2 => value2.... } creates a REFERENCE to an anonymous hash.
   	# Since reference are SCALAR, we assign it to a scalar variable
   	my $hashref = { index1 => $value1, index2 => $value2, index3 => $value3 };
	
	print "Done.\n",
	      "  \$hashref: ",$hashref,"\n";
	print "  content: ",$$hashref{'index1'},",",$$hashref{'index2'},",",$$hashref{'index2'},"\n";

	print "Adding \$hashref to our array... ";
	push( @myarray, $hashref );

	print "Done. There are currently ", scalar(@myarray), " elements in \@myarray.\n";
	print "Accessing last element of our array...";
	print " content: @myarray[$#myarray], ${@myarray[$#myarray]}{'index1'} our better yet @myarray[$#myarray]->{'index2'}\n";
}

print "\n\nNow we will traverse our array again...\n";
foreach ( @myarray )
{
	print 	"$_ containing ",
	 		"index1 => $$_{'index1'},",
			"index2 => $$_{'index2'},",
			"index3 => $$_{'index3'}\n";
	print 	"... or using -> operator: ",
	 		"index1 => $_->{'index1'},",
			"index2 => $_->{'index2'},",
			"index3 => $_->{'index3'}\n";
}

CPAN - Perl Packages

First time launch:

$ cpan                                       # ... OR ...
$ perl -MCPAN -e shell                       #  --> yes auto config

To adapt config related to proxy:

cpan> o config init /proxy/                  # (to enter an empty string, simply enter 1 space char as a value)
cpan> o conf commit

To install a Perl package (eg. here package GetOpt::Long):

$ cpan
cpan>install GetOpt::Long

Editing the configruation:

cpan> o conf init                            # Reset the configuration
cpan> o conf http_proxy http://proxy:8080/   # Edit a given variable (eg. here changing proxy settings):
cpan> o conf commit                          # To commit changes in the configuration
cpan> o                                      # to get o options
cpan> o conf                                 # To get o conf option

To edit CPAN database url:

cpan> o conf /urllist/
cpan> o conf init /urllist/
cpan> o conf urllist shift
cpan> o conf urllist unshift ftp://my.new.site/
cpan> o conf commit

To update CPAN itself:

cpan> install Bundle::CPAN
cpan> reload cpan