Category Archives: perl

Hacking # in OS X

To get a # sign on an Apple keyboard you use the Option (or Alt) key + 3. This seems terribly klunky to me, and # is of course used quite a bit in programming and sysadmin work. This hack remaps another … Continue reading

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A (very) short list of Dist::Zilla tips

For App::fooapp type distributions then you might want the README etc generated from a specific file. Add this to dist.ini: main_module = bin/fooapp ; btw, semicolon leads a comment, in case you forgot how to do that Any Module::Install converts reading this should note the bin directory, not script. In bin/fooapp itself you also provide an additional metadata hint (next to ABSTRACT): # PODNAME: fooapp Which results in nifty Metacpan links such as: Finally this hint to the POD munger will allow a section to be pinned in place above the SYNOPSIS: =begin :prelude # POD here… =end :prelude I hope these tips are helpful to some…… Continue reading

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Painless MythTV Channel Configuration

MythTV – a brilliant homebrew digital video recorder system. Killer features include being able to play content over the LAN at home, scheduling recordings via the web, and generally poke it to integrate with all kinds of devices (e.g. see … Continue reading

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Hosting the AutoCRUD Demo

In my previous entry here (syndicated from, I linked at the end to a demo Catalyst::Plugin::AutoCRUD application running on DotCloud. I’m much happier with this than running something on my own personal server, and here’s the notes on its setup. … Continue reading

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AutoCRUD revamped

For a couple of years I’ve been planning to rip apart and put back together the guts of Catalyst::Plugin::AutoCRUD, to address limitations in the initial implementation. After changing job and moving house I’m pleased this finally came to the top of my hacking stack. Nothing was going to happen however before I could work out how to do one thing: achieve independence from DBIx::Class as a “storage engine”. I love DBIx::Class, but it would be much more cool to support any data storage system able to represent a table+column paradigm (even things like CSV, as a test case). So SQL::Translator hit me like a thunderbolt. Of course, that’s exactly what it does – introspect some data storage and provide a neutral, class-based representation of the tables and columns (fields). It’s a little rough around the edges, but certainly good enough. The Translator provides a metadata structure which AutoCRUD’s web front-end can use, independent of any particular storage engine such as DBIx::Class. This also paves the way for development of display engines other than the bundled ExtJS and simple HTML offerings. Right now there’s a developer release of AutoCRUD on CPAN, and I hope shortly to have a production release. Whilst the web side might not look much different, the fact is that it can now support significant features such as tables with composite/compound primary keys, or no primary keys for that matter, database views, relations to self, multiple relations to the same table, and so on. Alongside that, I’ve taken the opportunity to fix a few quirks of the web interface, and chomp my way through the outstanding wishlist. The updated code is now running on a DotCloud instance, so please go and have a play! p.s. a cron job will restore the demo’s databases at the top of every hour… Continue reading

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Releasing trial/dev/beta versions with Dist::Zilla

You might have stumbled across Dist::Zilla’s –trial command line option in the past, and maybe even used it for a developer CPAN release. Its effect is (as I understand it) two-fold: adds -TRIAL to the name of the distribution archive being produced sets release: testing in the META.json file which is parsed by CPAN services It came to my attention that using -TRIAL is actually pretty bad for you and your system, and other users, even though it’s one of the two naming conventions CPAN services use to identify developer releases. The problem is that the actual $VERSION of your code is unaffected. This means once installed, you can’t ask your computer the version of an installed distribution and work out from that whether it’s a developer release, or not. A secondary issue is that in sites such as there’s nothing really obvious about the release which highlights its status as "development", in the list of available versions. An alternative way to signal to CPAN services that a dist is a trial release is to use an underscore and a secondary version number at the end of $VERSION, like _001. This is still a bit crappy but at least humans can really easily see what’s going on. Back to Dist::Zilla. If you use the AutoVersion plugin, a better alternative than using –trial is to set the DEV environment variable when you build or release the distribution. This has the effect of: (sprintf ‘_%03u’, $ENV{DEV}) being added to the end of $VERSION sets release: testing in the META.json file which is parsed by CPAN services Otherwise the best thing to do right now is to set the version manually, for developer releases. I hear from chatter on IRC that there are plans to change the –trial feature of Dist::Zilla to alter $VERSION if necessary (that is, if no underscore exists) – a good compromise, I reckon…. Continue reading

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local::libs for Dist Development

Most of my distributions are on GitHub and built using Dist::Zilla. As the dependencies of each vary widely and I don’t want to muck up my workstation’s libraries, I set up a local::lib for each distribution’s development. The App::local::lib::helper scripts make this really easy. As per the docs, I combine the helper with App::cpanminus (cpanm) for all installation. To bootstrap a new local::lib area, I wrote this simple shell script: #!/bin/bash # script named "new-ll" if [ -z $1 ] then echo ‘pass the distribution name, please’ exit fi echo "creating local::lib for $1 …" sleep 3 curl -L | perl – –notest –quiet –local-lib \ ~/perl5/$1 \ App::cpanminus \ Dist::Zilla \ App::local::lib::helper . Entering the correct environment for a distribution uses another helper script: #!/bin/bash # script named "go" if [ -z $1 ] then echo ‘pass the distribution name, please’ exit fi ~/perl5/$1/bin/localenv bash . Which means my workflow for a new distribution is: $ new-ll New-Dist-Name $ go New-Dist-Name . Any Perl distributions installed in that shell (for example from dzil authordeps | cpanm or dzil listdeps | cpanm) will be placed into the new local::lib. It’s a simple ^D to exit. However it’s not obvious that you’re within this special environment, so editing Bash’s $PS1 variable (the shell prompt) to include the following, can help: echo $PERL5LIB | cut -d’/’ -f5 . My deep thanks to the authors of the distributions used to create this neat setup…. Continue reading

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Perl on a Windows 7 laptop

I’ve been setting up my Windows 7 laptop to have as complete a Perl development environment as possible. I don’t have a choice about the operating system in this case, but I am used to the Unix-style environment, which I’d like to maintain. One option is to use Cygwin and just dive into there for everything. However I do want some of my code to work natively under Windows so there is still a need to run Perl tests at a Windows console. I might as well develop there too, if I can. I’ve ended up with the following steps, which are in places bodgy hacks, but show the principle works at least: Git for Windows Strawberry Perl Vim fix Windows Console perldoc fix local::lib cpanm installer Local CPAN mirror First thing is to install Git for Windows, known as msysgit (don’t alter any of the Windows PATH settings at install time). It’s a great little system which ships with Bash, Vim, and a suite of other handy tools. On this platform you probably want to set the End Of Line character(s) to ensure consistency. I have the following in my ~/.gitconfig: [core] editor = vim eol = lf [color] ui = true The bundled Perl in msysgit is a little ancient (5.8.8). Download and install the excellent Strawberry Perl distribution. Our goal is to have perl within the msysgit environment be Strawberry Perl’s perl. Move C:\Program Files\Git\bin\perl.exe out the way (to perl-g.exe) and copy C:\strawberry\perl\bin\perl.exe in its place (there are no symbolic links under Windows). By changing the Perl though, you knacker parts of Git which use Perl (for example git commit –interactive). The way to fix this is to keep a copy of the original msysgit perl (as above) and then edit any of the scripts in C:\Program Files\Git\libexec\git-core to have #!/usr/bin/perl-g at the top. Here’s a list: git-add–interactive git-svn git-difftool git-relink git-send-email The msysgit bundled Vim also needs some help, in the form of syntax files. I downloaded and installed GVim for Windows, and copied the .vim files from C:\Program Files\Vim\vim73\syntax to C:\Program Files\Git\share\vim\vim73\syntax but perhaps there’s a less brute-force way. At the least, you should get hold of perl.vim and pod.vim. The Windows console program leaves a lot to be desired. I found a reasonable alternative in the form of Console2, an open source project hosted on Sourceforge. Download and install that (well, copy to Program Files). You’ll definitely want to edit its Settings so under Hotkeys, set Close tab and Rename tab to an alternative, or None (by doing Clear then Assign for each). Also under Settings in the Console section I set the Shell to be C:\Program Files\Git\bin\sh.exe –login -i and the Startup dir to be a folder I created in my user area for Perl development. Now, pinning the Console2 application to the Start Menu means it can be opened straight into msysgit’s Bash. At the shell I installed my own vimrc file to ~/.vimrc, and created a ~/.bash_profile containing the following: alias ll="ls -l –color" alias view="vim -R" export TERM=vt100 Strawberry Perl ships with many useful tools in its bin directory. Some of them are Windows batch files (.bat) because the expectatation is that you’re running Perl from the native Windows console. In this setup we’re within a Bash shell so they don’t work. One thing you’ll probably miss is perldoc, so create a ~/bin directory and in ~/bin/perldoc put the following: #!/usr/bin/perl require 5; BEGIN { $^W = 1 if $ENV{‘PERLDOCDEBUG’} } use Pod::Perldoc; exit( Pod::Perldoc->run() ); I always use a local::lib area for the modules used in my development, and Strawberry Perl ships with this module. Simply run the llw32helper program from the normal Windows console and it’ll ask you for the new local::lib location then set Registry entries appropriately. One reboot later and perl -V should include this new library path. From Strawberry Perl’s CPAN shell (perl -MCPAN -e shell) I only install one module – App::cpanminus. This provides a new tool, cpanm, for installing modules. Note that since the previous local::lib setup, App::cpanminus is installed to that location rather than Strawberry Perl’s standard library path. The final step is to have a local CPAN mirror. This means I can work on the Windows 7 laptop from a remote part of a Scottish Hebridean island, for instance, fully off-line. This uses the CPAN::Mini and CPAN::Mini::Webserver modules, both installed via the cpanm utility. The minicpan command line app will create the mirror for you. The minicpan_webserver app fires up an interface at http://localhost:2963/. Here are example commands used with this setup, which I’ve made into Bash aliases (also set your ~/.minicpanrc as per the docs): minicpan -l /path/to/local/minicpan -r cpanm –mirror file:///C:/path/to/local/minicpan –mirror-only -v Module::Name A remaining niggle is that cursor keys don’t seem to work in less (Ctrl-N and Ctrl-K are alternatives). I’ve not yet found a fix for this; however they do work in Vim. Another issue I found is that, bizarrely, cpanm sometimes fails unless the -v option is provided. Also with cpanm it seems more successful at unpacking dist tarballs when treating the local platform as UNIX rather than WIN32 so I hacked the script to do that. I wish I were more capable on this platform to begin to debug this (please email me if you want to collaborate). That’s pretty much where I’m at, right now. I’d welcome constructive feedback on this process in the comments (at if you’re reading a syndication). My deep thanks and respect to all the developers of the above tools and libraries, who have made this possible…. Continue reading

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Dist::Zilla::PluginBundle::Author:: namespace

Following the lead of Mike Doherty (DOHERTY) I’ve moved my own Dist::Zilla Author PluginBundle into a new namespace: Dist::Zilla::PluginBundle::Author::OLIVER Having Author PluginBundles is a great system for saving me time and allowing others to build my modules with ease. However I had to agree to Mike’s point that polluting the Dist::Zilla::PluginBundle:: namespace wasn’t so cool. It also makes things more clear in the dist.ini file: [@Author::OLIVER] If you have an Author PluginBundle, please consider moving it into this new namespace. You can of course keep the old one around, in parallel, until code using it has moved off to the backpan…. Continue reading

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Adding a new RANCID device class

The RANCID system is used by many network service providers to backup and audit their network device configurations. It supports many device vendors (Cisco, Juniper, etc) but you might run into a vendor which is not supported. Adding a new … Continue reading

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