Basic System Administration

Bradley Anderson will give a talk at YAPC::NA 2012 described as:

If you are new to Perl, chances are one of the first things you’ll be doing is some light system administration.  You will soon discover that there are several things you do repeatedly … like, every day, or, multiple times per day.  My rule is: if I have to do it more than once, I write a script to do it.  In this talk, I’ll show you how to hop along as a system admin if you’re a Perl programmer.  It’s better than unicorn meat.

[From the YAPC::NA Blog.]

Perl vs Shell Scripts

Last week, I posted on my Other Blog about how I still prefer to use tcsh for my interactive shell.  Of course, I maintained that bash was the only real choice for shell scripts.

User friendly command line apps with even less suffering

I love to write command line applications (eg. App-iTan, Business-UPS-Tracking, Game-Lacuna-Task, Mac-iPhoto-Exif and many more not publicly available). However most of the CPAN tools I generally use to build these applications either are not as user-friendly as I would like them to be, or are not flexible enough.

I decided to change that and wrote MooseX-App.

It handles commands with multiple subcommands, generates usage text, error messages on wrong user-input, validates options, and lets you write your program as easy-to-test and reusable classes. Just as App-Cmd (or MooseX-App-Cmd respectively). However compared to these options it ...

  • is more flexible
  • supports plugins that can overdrive almost all of its behaviour
  • does not impose a certain application structure on you (thus making code reusage and testing easier)
  • does not pollute your command classes with many methods since most of its logic is implemented via meta classes
  • and is quite user friendly by providing useful input hints, better error messages as well as optional colorful output and bash completion

So let me give you a short example:



Hope you like it.

The Simplest Thing That Could Possibly Work

It should go without saying that when you are writing a book, you need to know how long the chapters are. I'm writing mine in vim, with various customizations to fit the needs of the book. However, I then need to convert my book into MS Word format. As I'm using Word 2008 for Mac, and as its the only version that does not have a scripting language built-in, formatting my plain text to the publisher's requirements is a long, tedious process. There are different headings, code, sample exercises, tables, images, "Try it out" sections, and many tiny, tiny details that need to be formatted correctly to ensure the book can be laid our properly.

About YAPC Game Night

We’ve had a few people email in to ask how to “submit” a game for the cPanel Game Night at YAPC::NA 2012. The event is free-form. There’s no reason to submit a game in advance. However, you are welcome to organize game events on the conference wiki.

[From the YAPC::NA Blog.]

And now Lisbon too...

So, apart from London, Oslo, and Zurich, I’m delighted to say that I’m now also going to be visiting Lisbon during my current European speaking tour…on May 3rd and 4th.

We’ll definitely be offering a public talk one evening for the local Open Source community (I’ll update when I have the details), but we’re also running a couple of public classes in Portugal for the first time in several years.

The classes are the recently updated Features of Modern Perls and the hugely popular Mastering Vim, and you can sign up for either (or both, with a discount) on the Caixa Mágica website.

I’m very much looking forward to catching up with many friends in Portugal next month. And, after what will have been nearly a full month in London and Oslo, and as lovely as those two cities are, I suspect I will secretly also be looking forward to some warm and sunny weather as well. ;-)

Damian

running perl with -MO=Deparse in node.js

I've hacked a '-MO=Deparse' option to perlito5. Now I can check the parser by comparing the output with perl:

$ node perlito5.js -Isrc5/lib -MO=Deparse -e ' ${ xxx{zzz}[3] } '
# Do not edit this file - Generated by Perlito5 9.0
use v5;
use Perlito5::Perl5::Runtime;
package main;
$xxx{'zzz'}->[3];
1;


compare to:

$ perl -MO=Deparse -e ' ${ xxx{zzz}[3] } '
$xxx{'zzz'}[3];
-e syntax OK

Reading the Federal Register with Perl

In case you're curious:

% grep -rli assassin federal_register | wc -l
      50

That's 50 mentions of "assassin" in the US Federal Register since early 2000. There's some interesting stuff buried in this publication.

Recently I wrote a post about more Americans giving up citizenship than reported. While I don't have exact numbers (they're hard to find), I managed to put together some information that seems to show that far more Americans are giving up citizenship than the Federal Register reports, but I'll skip the background.

Basically, I decided to download the entire Federal Register in XML format (it's in the public domain, too). Unfortunately, this snippet of code is not going in the book.

At YAPC::NA 2012 we’re introducing YAPC Bingo! These cards...



At YAPC::NA 2012 we’re introducing YAPC Bingo! These cards are a fun way to help make sure you get the most out of YAPC. You can cross each thing off as you accomplish it working your way toward a bingo. Or maybe, if you’re an over achiever, you’ll attempt to cross off all 25 and achieve a mega-bingo!

[From the YAPC::NA Blog.]

Announce: CGI::Snapp::Dispatch with PSGI support

I've uploaded to CPAN:

o CGI::Snapp::Dispatch V 1.00.

This distro includes CGI::Snapp::Dispatch::Regexp.

Both modules support usage in a PSGI environment.

This module is a partner for CGI::Snapp, and together they are almost drop-in replacements for CGI::Application, CGI::Application::Dispatch, CGI::Application::Dispatch::Regexp and CGI::Application::Dispatch::PSGI.

The default for logging is to not create a logger, as per CGI::Snapp V 1.01 below.

There are 63 tests.

PSGI is supported without needing a module called CGI::Snapp::Dispatch::PSGI.

o CGI::Snapp V 1.01.

This has a new mutator _psgi() for use by CGI::Snapp::Dispatch.

Also, the default for logging is now to not create a logger.

PSGI is supported without needing a module called CGI::Snapp::PSGI.

o CGI::Snapp::Plugin::Forward V 1.01.

The tests explicitly create a logger since CGI::Snapp V 1.01 now does not.

o CGI::Snapp::Plugin::Redirect V 1.01.

The tests explicitly create a logger since CGI::Snapp V 1.01 now does not.

I love Github

Github makes accepting patches from other people and applying them soooooo easy!

Instead of having to extract the patch from an email onto my workstation and manually apply it, applying this contribution was a simple matter of clicking on one button.

Thanks Mark - and thanks Github as well!

Simple HipChat notifier

We needed a simple way of sending messages to HipChat (great online chat software, BTW), so I cooked up this:


#!/usr/bin/env perl

use strict;
use warnings;
use WWW::Mechanize;

# See https://www.hipchat.com/docs/api/method/rooms/message for info
my $url = 'https://api.hipchat.com/v1/rooms/message';
my $api_key = 'your-api-key';
my $from = 'User-to-post-as';
my $room = 'room-to-post-to';
my $message = $ARGV[0];
my $color = $ARGV[1];

my $mech = WWW::Mechanize->new;
$mech->post( $url, {
room_id => $room,
from => $from,
color => $color,
message => $message,
auth_token => $api_key,
});

Quick and dirty - no error checking. Works well for the situations we are using it in, but you may wish to make something more robust before doing anything serious with it.

Enjoy!

Start Planning Your YAPC Strategy

From guest contributor brian d foy:

Conferences are virtually non-stop activity, networking, hacking, and socializing. YAPC, which is only three days, will have over 400 people moving around between talks, between buildings, and to other places in Madison. There’s a lot more going on besides the conference schedule: you don’t need to show up to hear the talks (they’ll be uploaded), but you do need to be there to hang out with people, carry on unstructured conversations in real life, and drink with other attendees.

The problem, though, is that many things are already in motion by the time that you step up to the registration table to get your badge. YAPCs have been going on for over a decade and many of the people already know each other in meatspace. They already know who they’ll go out with in the evening, they already know who they want to pair program with, and .

You need to start planning your YAPC strategy early and start lining up the things you want to accomplish.

A little help in VIM...

Explaining Web Programming via Plack

I'm currently writing Chapter 15 of my Beginning Perl book and it's about Web programming. The first part is about server-side software and the second part is about clients.

When I finally sat down to write about Web applications, I thought of what I should do. Some of you may remember my old Web programming course, but that was written around CGI and just wouldn't do. So I need to use something modern, but since I have a deadline, that means writing about something I know fairly well. That seemed to leave me with two primary options: Catalyst or Dancer. The latter is easier to use, but still "magical" enough to hide things I wanted to explain. Exploring other options would mean learning to use them and possibly missing a deadline.

That's when inspiration struck.

make test errors failed to map segment from shared object

I had to install a version of Storable 2.30 for a client on their server and was getting the following error

failed to map segment from shared object: Operation not permitted
Can't load '/tmp/del/Storable-2.30/blib/arch/auto/Storable/Storable.so' for module Storable: /tmp/del/Storable-2.30/blib/arch/auto/Storable/Storable.so: failed to map segment from shared object: Operation not permitted at

The error was due to the fact that I was trying to build and run the tests on a /tmp directory which had noexec enabled , moving to a different directory solved this issue

Practical Tools for Perl Emergencies

Josh Jore will give a talk at YAPC::NA 2012 described as:

This is a collection and walkthrough of things I’ve found useful for debugging emergencies in production.

[From the YAPC::NA Blog.]

Perl 6 Tablets: what happened this week

We're consolidating. Quality of about 50 entries was raised, escape chars for zero width assertions added, precedence table updated, better explanation of this compile time / runtime thing, the flipflops and zip operator.

And hurray i got help from raiph mellor, who has ambition to stay and constantly raise the quality.

But main news is something else. Im done with socialtext. Really. I had to dance around the syntax all the time, never knowing how this character would be displayed or if I had to put {{ }} around it. But even that doesn't helped --> which is used in Perl 6 in signatures to define the return type. And to make headlines, that also work as a link to the top of the page was sheer impossible. Lets not speak about beauty. So I left the wiki and moritz++ was kind to set up the URL http://tablets.perl6.org/, were further development will take place. This means you can easily fork it. Its just html for now, but lot more automation for generating html, pdf and pod (for Perl6::Doc) I expect to happen.

Marpa v. Parse::RecDescent: some numbers

The application

In a recent blog post, Flavio Poletti described an unusual language, one which he'd written a parser for, using the very traditional method of recursive descent. Specifically he'd used Perl's Parse::RecDescent module. Several people asked me how Marpa would do on this language. This post contains a comparison, including a benchmark.

The reader who wants an exact description should look at Flavio's post and code . I call it a Dyck-Hollerith language because it combines Hollerith constants (strings preceded by a count), with balanced parentheses (what is called a Dyck language by mathematicians). Here's Flavio's example:
A2(A2(S3(Hey)S13(Hello, World!))S5(Ciao!))

When I did a Marpa versus Perl regexes comparison, I was very careful to choose an application which showed Marpa in a good light. Here I did not pick the application, and it is almost as if it was designed to show recursive descent in a good light.

Nordic Perl Workshop 2012 - June 4-5 in Stockholm, Sweden

On the 4th and 5th of June the 2012 edition of Nordic Perl Workshop takes place
in Stockholm, Sweden. It'll be two days of presentations, hacking, socializing
and other interesting stuff around Perl5, Perl6, the community, projects and
related topics.

Regular attendee fee is 50 EUR and for students a reduced fee at 25 EUR.

Afterwards my hope is to have a hackathon and some touristy stuff for those
who are interested.

In order for the workshop to be great we also need interesting presentations
which my hope is that you attendees will provide! Last submission date is May 6th.

Thanks to Init AB who are sponsoring this year.

See you in Stockholm early June!

To register, submit talks or more information visit the workshop site at
http://act.yapc.eu/npw2012/

/Claes Jakobsson, Stockholm Perl Mongers

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