Let’s say you have three disks but you wish to share with Samba or NFS clients.

Of course you could just mount the disks on three separate mount points and export those. Or you could mount the three disks on three mount points inside the same directory and export the parent directory. The problem with both solutions is you have to “balance” the data among the disks – and it will make navigating your TViX, WDTV or Popcorn more annoying.

You could use RAID or LVM to handle all this for you. But. What if you already have data on the disks? What happens if one of the disks dies? With RAID0 or LVM your data is gone.

Luckily you can have the best of both worlds: mhddfs

mhddfs is a FUSE plugin that combines data from several directories and present it in one directory. The only downside is that you do not know (or control) where a file is created. Let’s say you combine /dir1, /dir2 and /dir3 under /virtual. Previously you had /dir1/my_content. This is now /virtual/my_content. If you write a file to /virtual/my_content it will not necessarily end up in /dir1/my_content. This also mean you can not predict what data is lost if you lose a disk.

The plugin is available in Ubuntu

$ sudo apt-get install mhddfs

Using it is pretty simple

$ sudo mkdir /export/hest
$ sudo mhddfs /dir1,dir2,dir3 /export/hest
[sudo] password for alj:
mhddfs: directory '/dir1' added to list
mhddfs: directory '/dir2' added to list
mhddfs: directory '/dir3' added to list
mhddfs: mount to: /export/hest
mhddfs: move size limit 4294967296 bytes

The “move size limit” deserves an explanation:

if free space size threshold if a drive has the free space less than the threshold specifed then another drive will be choosen while creating a new file. If all the drives have free space less than the threshold specified then a drive containing most free space will be choosen.

Default value is 4G, minimum value is 100M.

Now you have the combined space of all three disks

/dir1;/dir2;/dir3
                      589G  329G  260G  56% /export/hest

To mount the combined directory during boot, at this to /etc/fstab:

mhddfs#/dir1,/dir2,/dir3 /export/hest fuse defaults,allow_other 0 0

You can export the combined directory using NFS or Samba. If you export the combined directory using NFS you need to add the fsid option in /etc/exports

/export/hest 192.168.1.0/24(fsid=2,ro,sync,crossmnt,no_subtree_check,insecure)

I’ve been using the excellent terminal emulator Terminator for a long time. Terminator sports (among other things) split screen hand “cluster support” (grouping of screens, making it possible to type the same thing in all terminals).

Example

In previous versions of Ubuntu (Terminator versions prior to 0.14) Terminator would pick all settings from GNOME Terminal, including character encoding (ISO-8859-15 in my case). Apparently this is no longer the case in Ubuntu 10.04, which has Terminator 0.14.

To use another encoding than UTF-8, add the following to ~/.config/terminator/config:

encoding = ISO-8859-15

Substitute ISO-8859-15 with whatever encoding you want.

Some other nice configuration options

scrollback_lines = 10000 # Scroll back size
focus = sloppy # sloppy focus, ie. the focus follows the mouse when moving the pointer to another split-screen

for more options, run man terminator_config.

I was pretty happy with solution to get notifications from Irssi though it had some shortcomings.

A couple of days ago a colleague made me aware of a Perl modules written by another colleague (Anton Berezin) called IPC::Message::Minivan which, it turns out, is perfect for my notification script. Basing the notifications on Minivan combine the speed of using something like Dbus locally (instant notifications) with the convenience of my previous script (notifications over the network, able to handle multiple clients).

This setup consists of three parts: The Minivan daemon, the Irssi script and the notification script.

As always my instructions are based on Ubuntu but should work on most Linux and Unix systems.

Installing the Minivan

IPC::Message::Minivan is not yet available directly through CPAN so we need to install it manually

  1. Download IPC::Messaging and IPC::Message::Minivan (and unpack them).
  2. Install dependencies: sudo apt-get install libjson-xs-perl libregexp-common-perl
  3. One could use dh-make-perl but I chose to install the two modules manually
    Basically run “perl Makefile.pl && sudo make install
    :~/devel/IPC-Messaging-0.01_12$ perl Makefile.PL
    Cannot determine license info from lib/IPC/Messaging.pm
    *** Module::AutoInstall version 1.03
    *** Checking for Perl dependencies...
    [Core Features]
    - Test::More                ...loaded. (0.72)
    - B::Generate               ...missing.
    - IO::Socket::UNIX          ...loaded. (1.23)
    - IO::Socket::INET          ...loaded. (1.31)
    - Storable                  ...loaded. (2.18)
    - Time::HiRes               ...loaded. (1.9711)
    - IO::Select                ...loaded. (1.17)
    - Module::Load::Conditional ...loaded. (0.22)
    ==> Auto-install the 1 mandatory module(s) from CPAN? [y] y
    *** Dependencies will be installed the next time you type 'make'.
        (You may need to do that as the 'root' user.)
    *** Module::AutoInstall configuration finished.
    Checking if your kit is complete...
    Looks good
    Warning: prerequisite B::Generate 0 not found.
    Writing Makefile for IPC::Messaging
    :~/devel/IPC-Messaging-0.01_12$ sudo make install
    [sudo] password for alj:
    /usr/bin/perl "-Iinc" Makefile.PL --config= --installdeps=B::Generate,0
    Cannot determine license info from lib/IPC/Messaging.pm
    *** Installing dependencies...
    [MSG] No '/home/alj/.cpanplus/custom-sources' dir, skipping custom sources
    [MSG] No '/home/alj/.cpanplus/custom-sources' dir, skipping custom sources
    [MSG] No '/home/alj/.cpanplus/custom-sources' dir, skipping custom sources
    *** Installing B::Generate...
    Running [/usr/bin/perl /usr/bin/cpanp-run-perl /home/alj/.cpanplus/5.10.0/build/B-Generate-1.26/Makefile.PL INSTALLDIRS=site]...
    # running Build.PL installdirs=site
    /usr/bin/perl Build.PL installdirs=site
    Creating custom builder _build/lib/My/Builder.pm in _build/lib/My
    Checking whether your kit is complete...
    Looks good

    Checking prerequisites...
    Looks good

    Creating new 'Build' script for 'B-Generate' version '1.26'
    Unknown 'build_class', defaulting to 'Module::Build'
    Running [/usr/bin/make test UNINST=1]...
    make[1]: Entering directory `/home/alj/.cpanplus/5.10.0/build/B-Generate-1.26'
    /usr/bin/perl Build --makefile_env_macros 1 test
    t/basic............ok
            2/10 skipped: various reasons
    t/inspect-btest....ok
    t/inspect-this.....ok
    t/new_cv...........ok
    t/op_list..........ok
    t/op_list_bgen.....ok
    All tests successful, 2 subtests skipped.
    Files=6, Tests=721,  0 wallclock secs ( 0.24 cusr +  0.21 csys =  0.45 CPU)
    make[1]: Leaving directory `/home/alj/.cpanplus/5.10.0/build/B-Generate-1.26'

    *** B::Generate successfully installed.
    *** Module::AutoInstall installation finished.
    cp lib/IPC/Messaging.pm blib/lib/IPC/Messaging.pm
    Manifying blib/man3/IPC::Messaging.3pm
    Installing /usr/local/share/perl/5.10.0/IPC/Messaging.pm
    Installing /usr/local/man/man3/IPC::Messaging.3pm
    Writing /usr/local/lib/perl/5.10.0/auto/IPC/Messaging/.packlist
    Appending installation info to /usr/local/lib/perl/5.10.0/perllocal.pod
    :~/devel/IPC-Message-Minivan-0.01_08$ perl Makefile.PL
    Cannot determine license info from lib/IPC/Message/Minivan.pm
    Writing Makefile for IPC::Message::Minivan
    :~/devel/IPC-Message-Minivan-0.01_08$ sudo make install
    cp lib/IPC/Message/Minivan.pm blib/lib/IPC/Message/Minivan.pm
    cp minivan blib/script/minivan
    /usr/bin/perl "-Iinc" "-MExtUtils::MY" -e "MY->fixin(shift)" blib/script/minivan
    Manifying blib/man1/minivan.1p
    Manifying blib/man3/IPC::Message::Minivan.3pm
    Installing /usr/local/share/perl/5.10.0/IPC/Message/Minivan.pm
    Installing /usr/local/man/man1/minivan.1p
    Installing /usr/local/man/man3/IPC::Message::Minivan.3pm
    Installing /usr/local/bin/minivan
    Writing /usr/local/lib/perl/5.10.0/auto/IPC/Message/Minivan/.packlist
    Appending installation info to /usr/local/lib/perl/5.10.0/perllocal.pod
  4. Create an Upstart script for the Minivan daemon
    $ cat /etc/init/minivan.conf
    # minivan - minimalistic message bus
    #

    description     "minimalistic message bus"

    start on runlevel [2345]
    stop on runlevel [!2345]

    expect fork
    respawn

    exec /usr/local/bin/minivan -l /var/log/minivan -d
  5. Start the Minivan daemon
    $ sudo start minivan

Install the Irssi script

  1. Copy the script to ~/.irssi/scripts/notifier-minivan.pl (the script below is just for reference, it might not be up to date)
    ## Put me in ~/.irssi/scripts, and then execute the following in irssi:
    ##
    ##       /load perl
    ##       /script load notifier-minivan
    ##

    use strict;
    use Irssi;
    use vars qw($VERSION %IRSSI);
    use HTML::Entities;
    use IPC::Message::Minivan;

    $VERSION = "0.01";
    %IRSSI = (
        authors     => 'Allan Willems Joergensen',
        origauthors => 'Luke Macken, Paul W. Frields, Jared Quinn, Anton Berezin, Kristoffer Larsen',
        contact     => '[email protected],dk',
        name        => 'notifier-minivan.pl',
        description => 'Alert the user of new messages or hilights through IPC::Message::Minivan',
        license     => 'Beerware',
        url         => 'http://www.nowhere.dk/articles/irssi-notifications-minivan',
    );

    # Default settings in Irssi
    Irssi::settings_add_str('notifier','minivan_host', 'localhost');
    Irssi::settings_add_str('notifier','minivan_port', 6826);
    Irssi::settings_add_str('notifier','minivan_channel','#irssi');

    # Fetch settings from Irssi
    my $minivan_host = Irssi::settings_get_str('minivan_host');
    my $minivan_port = Irssi::settings_get_str('minivan_port');
    my $minivan_channel = Irssi::settings_get_str('minivan_channel');

    # Connect to the Minivan
    our $van = IPC::Message::Minivan->new(host => $minivan_host, port => $minivan_port);

    sub notify {
        my ($server, $summary, $message) = @_;

        # Encode certain characters using HTML
        my $safemsg = HTML::Entities::encode($message, '<>&"');

        # Load everyone into the minivan
        $van->msg($minivan_channel, {summary => $summary, msg => $safemsg});
    }

    sub print_text_notify {
        my ($dest, $text, $stripped) = @_;
        my $server = $dest->{server};
        return if (!$server || !($dest->{level} & MSGLEVEL_HILIGHT));
        my $sender = $stripped;
        $sender =~ s/^\<.([^\>]+)\>.+/\1/ ;
        $stripped =~ s/^\<.[^\>]+\>.// ;
        my $summary = "Hilite in " . $dest->{target};
        notify($server, $summary, $stripped);
    }


    sub message_private_notify {
        my ($server, $msg, $nick, $address) = @_;
        return if (!$server);
        notify($server, "Private message from ".$nick, $msg);
    }

    sub dcc_request_notify {
        my ($dcc, $sendaddr) = @_;
        my $server = $dcc->{server};

        return if (!$dcc);
        notify($server, "DCC ".$dcc->{type}." request", $dcc->{nick});
    }

    Irssi::signal_add('print text', 'print_text_notify');
    Irssi::signal_add('message private', 'message_private_notify');
    Irssi::signal_add('dcc request', 'dcc_request_notify');
  2. Load the script inside Irssi: /script load notifier-minivan.pl
  3. If your Minivan is not running on the same machine as Irssi, change the configuration inside Irssi:
    /set minivan_host your_hostname – IPC::Message::Minivan is tunnel-able through ssh, see client configuration
  4. Auto-load the script:
    ln -sf ~/.irssi/scripts/notifier-minivan.pl ~/.irssi/scripts/autoload/notifier-minivan.pl

The stuff running on your local machine

It is possible to use autossh to automatically setup the tunnel but since I am always connected to my server (at least when I am in front of a computer) I chose to use normal ssh port forwarding.

In ~/.ssh/config I have

Host my.server.bogus
        LocalForward 6826 localhost:6826

The stuff that actually shows the notifications

I did not want to bother trying to make the script error proof so I simply call the Perl script from a shell script like so

#!/bin/bash

wait=0
while true
 do
    $HOME/bin/irssi-notify-client.pl

    let wait=$wait+5
    if [ $wait -ge 30 ]
     then
        sleep 30
    else
        sleep $wait
    fi
done

Save the script as ~/bin/start-irssi-notify-client.sh

The notification script requires Desktop::Notify – It is available in the Ubuntu repositories but it is an old version, so let’s use a newer:

$ sudo apt-get install dh-make-perl libnet-dbus-perl
$ cpan2deb Desktop::Notify
$ sudo dpkg -i ~/.cpan/libdesktop-notify-perl*.deb

The script

#!/usr/bin/perl

use strict;
use warnings;
use Desktop::Notify;
use IPC::Message::Minivan;
use Encode;

my $notify_timeout = 500;
my $icon = "/usr/share/pixmaps/pidgin/protocols/scalable/irc.svg";
#my $icon = "gnome-irc.png";

my $van = IPC::Message::Minivan->new(host => 'localhost');
$van->subscribe("#irssi");
our $notify = Desktop::Notify->new();
my $notification = $notify->create(summary => 'Minivan', body => 'Connection established', timeout => $notify_timeout, app_icon => $icon);
$notification->show();

while (1) {
    if (my $cmd = $van->get(5,[])) {
        if ($cmd->[0] eq '#irssi') {
            my $c=$cmd->[1];
           
            my $message = Encode::encode("utf-8",$c->{msg});
            my $summary = $c->{summary};
           
            $notification->summary($summary);
            $notification->body($message);
            $notification->show();
        }
    }
}

$notification->close();

Copy the script to ~/bin/irssi-notify-client.pl.

Remember to make both scripts executable.

The final thing to do is to add the notify client to your desktop environment’s autostart

In GNOME: System -> Preferences -> Startup Applications

Add Startup Program

Add Startup Program

Since I run irssi all the time, packing as many features into it as possible seems like a nice idea.

So I use bitlbee to connect to Messenger, Google Talk/Jabber and ICQ and I have been using tircd (Twitter/irc gateway) and tweet.im (Twitter/Google Talk gateway) to connect to Twitter; but none of them works like I want them to.

Today I stumbled across Twirssi, a script for irssi to interact with Twitter.

Out of the box twirssi expects input to be UTF-8 which caused some grief because my terminal is ISO-8859-15.

First, lets install required modules for twirssi

I run Ubuntu Karmic Koala so Net::Twitter is available as a package

$ sudo apt-get install libnet-twitter-perl

If you run an older Ubuntu release or another Linux/Unix variant that does not have a native package, install it from CPAN (I will not go into the configuration of CPAN here – have a look at this article for more information).

$ sudo perl -MCPAN -e shell
cpan[1]> install Net::Twitter

Answer yes to all dependencies.

Next step is to install a Perl module for the URL shortening service you wish to use; I use Bit.ly so let’s install the module

$ sudo perl -MCPAN -e shell
cpan[1]> install WWW::Shorten::Bitly

Now, let’s install twirssi

Head to irssi’s scripts directory

$ cd ~/.irssi/scripts

Download the script

$ wget http://twirssi.com/twirssi.pl

Make sure the script is autoloaded at startup

$ cd autorun
$ ln -sf ../twirssi.pl .

Patch twirssi to support other charsets than UTF-8

$ cd ~/.irssi/scripts
$ wget http://people.freebsd.org/~garga/patches/twirssi_charset.diff
$ patch -p1 < twirssi_charset.diff

Finally, configure twirssi

The configuration is done from inside irssi

  1. Create a new window for twirssi
    /win new hidden
  2. Name the new window
     /win name twitter
  3. Optional: Move the new window to another location
    /win move <number>
  4. Optional: Save new window layout
    /layout save
  5. Load twirssi
    /script load twirssi.pl
  6. Configure URL shortening service
    /set short_url_provider Bitly

    /set short_url_args "Bitly API key"
  7. Configure Twitter usename
    /set twitter_usernames Your_Twitter_Username

    /set twitter_passwords Your_Twitter_Password

    (Note: This will store your Twitter password in clear text in irssi’s configuration)

  8. Set charset to use
    /set twirssi_charset ISO-8859-15
  9. Reload the script to pickup autologin to Twitter
    /script load twirssi.pl

More information on how to use twirssi is available here