Notes

PSGI

Plack

Plack::Middleware::StackTrace

If you want Excel to keep a field’s leading zeros when opening a CSV file using Excel, you can change it to =”value”.

For example, if you have a row with 4 values that looks like this:

test,00016102,test,test

Just change it to:

test,="00016102",test,test

The Ternary Operator

The ternary is actually a sequence of operators. The operator is used like this:

CONDITION-PART ? TRUE-PART : FALSE-PART

which is shorthand for the following statement:

if (CONDITION-PART) {

TRUE-PART

} else {

FALSE-PART

}

Example: If $firstVar is zero, then assign $secondVar a value of zero. Otherwise, assign $secondVar the value in the first element in the array @array.

$secondVar = ($firstVar == 0) ? 0 : $array[0];

via Perl 5 By Example.


if ( $string =~ /[[:^ascii:]]/ ) {
print "String contains characters that are NOT pure ASCII";
}
else {
print "Everything is good, string/pure is valid ASCII.";
}


E.G.: If it contains bytes > 127, it’s not valid ASCII.

It allows you to get Perl pre-compiled packages. You can avoid installing a C compiler which is needed for some packages (KinoSearch for example).

http://aspn.activestate.com/ASPN/Downloads/ActivePerl/PPM/

Alternate packages repositories:
http://cpan.uwinnipeg.ca/PPMPackages/10xx/

KinoSearch is the winner

The following perl scripts index *.txt in the current folder and search for “TEST”. The first one is using Perl’s KinoSearch module and the other one is using Plucene. KinoSearch is alot faster then Plucene and also gives better results.

(right click to download)

KinoSearch.pl

Plucene.pl

1. Setup cpan:

$ mkdir ~/perl
$ mkdir -p ~/.cpan/CPAN
$ touch ~/.cpan/CPAN/MyConfig.pm
$ cpan

cpan> o conf init

Set the following settings:

'cpan_home' => q[/home/username/.cpan],
'build_dir' => q[/home/username/.cpan/build]
'keep_source_where' => q[/home/username/.cpan/sources],
'makepl_arg' => q[PREFIX=~/perl]
'mbuildpl_arg' => q[--install_base /home/username]

2. Get and Install the Module
   • Automatically

     • $ cpan force install Module::Name

3. Make sure Perl can find your modules

Add this line in each of your Perl scripts (change perl version accordingly):

use lib '/home/your_username/perl/lib/perl5/site_perl/5.8.7';

OR rather than editing all your Perl scripts, in your cgi-bin/.htaccess file:

SetEnvIf  Request_URI  "^/cgi-bin/" PERL5LIB=/home/user/perl/lib/perl5/site_perl/5.8.7:/home/user/perl/lib/perl5/site_perl/5.8.7/site_perl

OR in your .bash_profile:

export PERL5LIB=/home/user/perl/lib/perl5/site_perl/5.8.7:/home/user/perl/lib:/home/user/perl/lib/perl5:/home/user/perl/lib/perl5/site_perl

It won’t be effective until you log back in, if you want to make it effective in your current session, just type that line in your command prompt.