Easy Password-less SSH logins on Linux

ssh-copy-idI’m storing this as an aide memoire, really, but it may help you too.

Let’s say we have two systems, System_From and System_To. And two users, User_From and User_To. The objective is: log on to System_To as User_To, from System_From as User_From.

The steps

1. One-time key generation for User_From

On System_From, while logged on as User_From, proceed as follows:

User_From@System_From:~$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/User_From/.ssh/id_rsa):[hit enter]
Enter passphrase (empty for no passphrase):[hit enter]
Enter same passphrase again:[hit enter]
Your identification has been saved in /home/User_From/.ssh/id_rsa.
Your public key has been saved in /home/User_From/.ssh/id_rsa.pub.
The key fingerprint is:
be:e8:98:4a:26:1e:9b:ed:78:a7:e7:fe:d8:9d:3c:6d User_From@System_From
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|  E              |
|                 |
|               Q |
|        S        |
|       .         |
|oo      o     o  |
|+.Bo8ooo.E       |
| BOB++o++        |

Note: if you use anything other than an empty passphrase, you will need to enter the passphrase each time you log on, which sort of defeats the object of this exercise!

This creates two files: id_rsa and id_rsa.pub. The private key, id_rsa, must always be kept secret. Your system should have marked it read/write for the owner only. The public key, id_rsa.pub is safe to copy to destination systems (see next section).

2. Copy the public key to System_To

OpenSSH comes with a handy script for copying the public key to the remote host (System_To, in this instance): ssh-copy-id. Use it like this, at the system you’re connecting from:

User_From@System_from:~$ ssh-copy-id -i ~/.ssh/id_rsa.pub User_To@System_To
User_To@System_To's password:[type User_To's password and hit enter]
Now try logging into the machine, with "ssh 'User_To@System_To'", and check in:


to make sure we haven't added extra keys that you weren't expecting.

If you’re connecting to SSH on a custom port, the command is thus:

ssh-copy-id -i ~/.ssh/id_rsa.pub "User_To@System_To -p custom#"

Repeat this step for all remote hosts to which you intend to connect.

3. Log in to System_To

Now, when you issue the command ssh System_To, you will be logged in straight away, with no password prompt.

SOLVED: “Access is denied, unable to remove” when deleting printer

It’s amazing to see that many years after I first wrote this post, visitors are still finding it useful!

If you really want to understand what’s going on under the hood, the Windows Internals books are the place to start. In the interests of transparency: this is an affiliate link. See my affiliate disclosure page for an explanation.

Many organisations push out printer installations via Active Directory. If you want to tidy up those printers (removing ones you don’t use) you may find Windows 7 doesn’t let you delete them, even though you may be a local administrator and even if you use an elevated Explorer session:

Access denied error

Use the following steps to resolve this annoyance.

From an elevated command prompt:

C:\Windows\system32>net stop spooler
The Print Spooler service is stopping.
The Print Spooler service was stopped successfully.

Then fire up regedit. Navigate to Computer\HKEY_CURRENT_USER\Printers\Connections and delete the offending printer:

printers regedit

Finally, restart the print spooler:

C:\Windows\system32>net start spooler
The Print Spooler service is starting.
The Print Spooler service was started successfully.

From CodeIgniter to Laravel | part 4: managing databases

UPDATE: I have re-written this article for the new Laravel 4. You’ll find the updated article over at Geek & Dummy.


AVZ DatabaseFor almost all my previous web design, I’ve used phpMyAdmin to administer the databases. I speak SQL, so that has never been a big deal. But Laravel comes with some excellent tools for administering your databases more intelligently and (most importantly!) with less effort. Migrations offer version control for your application’s database. For each version change, you create a “migration” which provides details on the changes to make and how to roll back those changes. Once you’ve got the hang of it, I reckon you’ll barely touch phpMyAdmin again.


So let’s assume that I’m creating a new website about ducks. When I created the virtual host, Virtualmin also created my “ducks” database. I’m going to create a MySQL user with the same name, with full permission to access the new database. Here’s how I do that from a root SSH login:

echo "GRANT ALL ON ducks.* TO 'ducks'@localhost IDENTIFIED BY 'newpassword';" | mysql -p
Enter password:[root MySQL password]

This creates a new MySQL user, “ducks” and gives it all privileges associated to the database in question. Next we need to tell Laravel about these credentials. The important lines in the file application/config/database.php are:

return array(


	'default' => 'mysql',

	'connections' => array(


		'mysql' => array(
			'driver'   => 'mysql',
			'host'     => '',
			'database' => 'ducks',
			'username' => 'ducks',
			'password' => 'newpassword',
			'charset'  => 'utf8',
			'prefix'   => '',





Initialise Migrations

The migration environment must be initialised for this application. We do this using Laravel’s command line interface, Artisan. From an SSH login:

php artisan migrate:install
Migration table created successfully.

This creates a new table, laravel_migrations, which will be used to track changes to your database schema (i.e. structure), going forwards.

My ducks application will have a single table to start with, called “ducks” [Note: it is significant that we’re using a plural word here; I recommend you follow suit]. This table does not yet exist; we will create it using a migration. To kick this off, use the following Artisan command:

php artisan migrate:make create_ducks_table
Great! New migration created!

This will create a new file named something like “2013_04_15_085356_create_ducks_table.php”. If, like me, you’re developing remotely, you’ll need to pull this new file into your development environment. In NetBeans, for example, right-click the migrations folder, click “download” and follow the wizard.

You can deduce from the naming of the file that migrations are effectively time-stamped. This is where the life of your applications database begins. The migrations file will look a bit like this:


class Create_Ducks_Table {

	 * Make changes to the database.
	 * @return void
	public function up()

	 * Revert the changes to the database.
	 * @return void
	public function down()


As you can probably guess, in the "up" function, you enter the code necessary to create the new table (to move "up" a migration) and in the "down" function, you do the reverse (to move "down" or to roll back a migration).

<h1>Create first table</h1>

Your first migration will probably be to create a table (unless you have already created or imported tables via some other method).  Naturally, Laravel has a class for this purpose, the <a href="http://laravel.com/docs/database/schema" target="_blank">Schema class</a>.  Here's how you can use it, in your newly-created migrations php file:


class Create_Ducks_Table {

	 * Make changes to the database.
	 * @return void
	public function up()
		Schema::create('ducks', function($table) {
				$table->increments('id');              // auto-incrementing primary key
				$table->string('name', 255);           // varchar field; length 255 characters
				$table->date('birthdate')->nullable(); // can be empty
				$table->timestamps(); // special created_at and updated_at timestamp fields

	 * Revert the changes to the database.
	 * @return void
	public function down()


To run the migration (i.e. to create the table), do the following at your SSH login:

php artisan migrate
Migrated: application/2013_04_15_085356_create_ducks_table

That creates the table, as described. And if you need to roll back:

php artisan migrate:rollback
Rolled back: application/2013_04_15_085356_create_ducks_table

This removes the table.

By examining the Schema class documentation, you’ll see how you can use future migrations to add or remove fields, create indexes, etc. In my next tutorial, I’ll have a look at using databases in your application.

AVZ Database image copyright © adesigna, licensed under Creative Commons. Used with permission.

From CodeIgniter to Laravel | part 3: installing external libraries

UPDATE: I have re-written this article for the new Laravel 4. You’ll find the updated article over at Geek & Dummy.


LibraryAs a fan of CodeIgniter, I was very pleased when the Sparks project came on the scene, offering a relatively easy way to integrate third-party libraries/classes into your project. Laravel has a similar and arguably more feature-rich analog in Bundles. With a bit of luck, the third-party library you require has already been converted to a Laravel bundle, making installation a snip.

Let’s say, for example, we’re going to build a web-scraping application. The first two libraries I’d consider adding to the project would be the Requests HTTP library and the PHP Simple HTML DOM Parser.

From an SSH login, at the root of your project, issue the following command:

php artisan bundle:install requests phpsimplehtmldom

You should be greeted with the following results:

Fetching [requests]...done! Bundle installed.
Fetching [phpsimplehtmldom]...done! Bundle installed.

The file application/bundles.php will probably contain code along the following lines:


 &#91;...various comments...&#93;

return array(

	'docs' => array('handles' => 'docs'),


Register the new libraries like this:

return array(

	'docs' => array('handles' => 'docs'),
	'requests' => array('auto' => TRUE),
	'phpsimplehtmldom' => array('auto' => TRUE),


And use like this:

		$HDM = IoC::resolve('HtmlDomParser'); // Give us a hook into the library; Requests doesn't need this

		// Request the HTML page
		//$headers = array('Accept' => 'application/html');
		$headers = array();
		//$options = array('auth' => array('user', 'pass'));
		$options = array();
		$request = Requests::get('http://some.domain/some/page', $headers, $options);
		if($request->status_code != 200) {
			// Handle error retrieving page

		$dom = $HDM::str_get_html($request->body);

		// Options
		$options = $dom->find('#somediv option');
		foreach($options as $option) {
			echo $option->value.' | '.$option->innertext."<br />";

There’s a lot more to this IoC thing than meets the eye. To be frank, it’s above my head. I’m also not convinced I fully understand registering bundles. But, like CodeIgniter, learning is a process of immersion in the framework. I’m pretty sure than in a couple of years I’ll laugh at the code above. So all I ask is please be gentle in the comments. 😉

Library image copyright © Janne Moren, licensed under Creative Commons. Used with permission.

From CodeIgniter to Laravel | part 2: orientation

UPDATE: I have re-written this article for the new Laravel 4. You’ll find the updated article over at Geek & Dummy.


Signpost at North Point, Barbados, Feb.1998I’ve used CodeIgniter for many years, but I have always, I confess, proceeded knowing just enough to get by. So forgive me if my approach seems a little clunky. I have never, for example, used CodeIgniter’s routes. I like my web application files nicely categorised into Model, View, Controller, Library and, if absolutely necessary, Helper.


So for now, I want to carry on using Controllers, if that’s okay with you. Controllers are stored under application/controllers. Sound familiar?

Here’s a sample controller:


// application/controllers/news.php
class News_Controller extends Base_Controller {

	public function action_index() {
		echo "News index page.";

	public function action_item($item) {
		echo "News item $item.";


In CodeIgniter, that’s all you would have needed to do, due to automatic routing. In Laravel, you need also to add the following to application/routes.php:


To view these pages, you just visit yourdomain/news (/index is implied) and yourdomain/news/item/x (where x will probably refer to a specific news item, possibly by data id).

Note the naming of the functions – action_item, etc. The part after the underscore represents a “method” or page of your web site. Laravel’s routing magic makes sure you get the correct function. If you’re creating a RESTful API, you can use additional function names beginning get_, post_, etc. Check the Laravel documentation for more.


Views are pretty straightforward and similar to CodeIgniter. Place them in application/views. Extending the example above, our controller could now look like this:


// application/controllers/new.php
class News_Controller extends Base_Controller {

	public function action_index() {
		echo "News index page.";

	public function action_item($id) {
		$data = array('id' => $id);
		return View::make('results', $data);



Note that data can also be passed through to a view like this:

	public function action_item($id) {
		return View::make('item', $data)
		    ->with('id' => $id);

And then your view (application/views/item.php) could be like this:

<h1>News flash</h1>
<p>This is news item <?php echo $id; ?>.</p>

Obviously your real views will be more syntactically complete.


Models are created under application/models. Unlike CodeIgniter, Laravel comes with its own object relational mapper. In case you’ve not encountered the concept before, an ORM gives you a convenient way of dealing with database tables as objects, rather than merely thinking in terms of SQL queries. CodeIgniter has plenty of ORMs, by the way, it just doesn’t ship with one as standard.

Laravel’s built-in ORM is called “Eloquent”. If you choose to use it (there are others available), when creating a model, you extend the Eloquent class. Eloquent makes some assumptions:

  • Each table contains a primary key called id.
  • Each Eloquent model is named in the singular, while the corresponding table is named in the plural. E.g. table name “newsItems”; Eloquent model name “newsItem”.

You can override this behaviour if you like, it just makes things a bit more convenient in many cases.

Example model application/models/newsItem.php:

class NewsItem extends Eloquent {


(You can omit the closing ?> tag.)

Because the Eloquent class already contains a lot of methods, you do not necessarily need to do more than this. In your controllers, you could for example now do this:

$items = NewsItem::all();

foreach ($items as $item) {
  // Do stuff here

This is barely scratching the surface. Head on over to the official Laravel documentation for much more on all this.

Signposts image copyright © Andrea_44, licensed under Creative Commons. Used with permission.

SOLVED: “Failed to initialize connection subsystem” in Cisco AnyConnect

AnyConnect logoTalk about obscure.

One of my end users was greeted by this informative error message recently. He was connecting to the internet using a 3G dongle and then to our network via Cisco AnyConnect VPN. “Software reinstall!” thought I. “Wrong!” said Google.

Although this is probably due to faulty programming on Cisco’s part, the culprit is Internet Explorer. (How I love to blame that historically stinky pile of poodoo.)

To resolve: load up IE. If you can’t see the [ File | Edit | View… ] menus, press Alt, to bring it up. On the File menu, “Work Offline” is almost certainly checked. Uncheck it. Connect again. Job done. Who knew.

If you’re using Internet Explorer 11, bad news: Microsoft removed the “Work offline” option from the File menu. Gone. So there’s no GUI interface to the relevant setting. In fact it’s a registry key called “GlobalUserOffline”, found at HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings. You need to set it to 0, disable “Work offline”. This registry file should do the trick: DisableWorkOffline.reg.

Tutorial: Merge multiple RTF files into a single PDF

A recent task of mine involved generating a large quantity of forms (around 2,500) and printing them. I was using PHP as the generator – it’s great at processing and transforming text. And my base (template) file was originally created as a Word document, converted to RTF for ease of processing.

There is no easy and free way of printing out 2,500 RTF files from Windows, not that I’ve been able to find. It didn’t make sense to pay for a £200 application for something that I do so infrequently. So here is my (free) approach.

Make Linux do the hard work

If you’ve followed my “Easily host your own web sites” series, you’ll now have a Linux server at your disposal that you can bend to your will. When it comes to command line or scripted activities (which this tutorial lends itself to), Linux/Unix is simply more mature than Windows. This means that someone, somewhere has probably already created a tool for whatever activity you’re thinking of and moreover, made that tool free.

Converting to PDF: Ted

Ted is a fairly full-featured text processor for Linux. We’ll just be using some of Ted’s command line wizardry today.

Installing Ted

Ted logoYou can download a Ted package here. I’m installing this on an Ubuntu 12.04.1 machine so I chose this package: ubuntu12041:ted-2.23-amd64.deb.

I keep all third party packages I install in a directory, /root/installed-packages, for future reference. So this is what I did, from a command line (SSH connection). First, I know that Ted has some dependencies, so I dealt with those:

apt-get update
apt-get install libxpm4 libtiff4 libgtk2.0-0 libpaper1
apt-get -f install

Then downloaded and install Ted:

wget http://ftp.nluug.nl/pub/editors/ted/ubuntu12041:ted-2.23-amd64.deb
dpkg -i ubuntu12041\:ted-2.23-amd64.deb

Combining files: pdfmerge

Abiding by the principle of “do one thing well”, guess what pdfmerge does?

Installing pdfmerge

If you’re using a RedHat-derived distribution, you’re in luck, there’s a pre-built package. If you’re using Ubuntu though, here goes. Download the source [iwrtooltip title=”a compressed archive of files”]tarball[/iwrtooltip] from here. Again, I’m starting in my directory /root/installed-packages.

wget http://dmaphy.github.com/pdfmerge/pdfmerge-1.0.4.tar.bz2
tar jxf pdfmerge-1.0.4.tar.bz2
cp pdfmerge-1.0.4/pdfmerge /usr/local/bin
rm -rf pdfmerge-1.0.4

Put it all together

Now the utilities are installed, you can run the following simple bash script to convert your individual RTF files into PDFs, then merge them all into a single PDF. I put the RTF files in one directory, then the PDF into the directory above it in the directory tree. We use a script that is bundled with Ted – you may need to check the precise location.

for filename in ./*.rtf
/usr/share/Ted/examples/rtf2pdf.sh $filename
pdfmerge *.pdf ../all.pdf


Thanks to Mark de Does for Ted and to Dominic Hopf for pdfmerge.

Self-hosted alternative to Google Reader: selfoss

No no no! Google has just announced it is shutting down Reader on 1 July 2013.

Personally, I can’t really understand this. It is a good product, with surely plenty of advertising and marketing opportunities. Nevertheless, there’s no point railing against the decision. It was “free”. It was good while it lasted. I shouldn’t complain.

Like many people, this leaves me scrabbling around for an alternative. There are one or two similar web-based services out there, but having been burnt once by the whim of a content publisher, I would rather take my destiny into my own hands going forwards. In short, this means setting up a web-based RSS reader on my own server.

There are a few features I’ve come to regard as indispensable in a news reader:

  • Keyboard shortcuts
  • Desktop- and mobile-friendly interfaces
  • No limits on number of subscriptions
  • Responsive (uses Ajax)

selfoss logoIt didn’t take too much searching to find a solution that looked ideal: selfoss. The author describes selfoss as:

The new multipurpose rss reader, live stream, mashup, aggregation web application

The features of selfoss that stood out most to me were:

  • web based
  • open source
  • mobile support (Android, iOS, iPad)
  • lightweight PHP application
  • supports MySQL

There are one or two similar projects out there, but selfoss most closely fits my requirements and seems to be in a good state of development. Interestingly, within 36 hours of Google’s announcement it was retiring Reader, a selfoss user called Michael Moore had written code for selfoss to import OPML files – which is the format we’ll be exporting from Google.

Preparing your web server

If you’ve followed my guide to DIY web hosting, you’ll be able to do what I did:

  • Create a new virtual server in Virtualmin (e.g. myfeeds.fredbloggs.com)
  • Configure my external DNS host to point to this new website (I host my main domains with GoDaddy and manage this through its DNS control panel)
  • Configure my local DNS server similarly (I run an internal DNS server, to avoid the problem of hairpin NAT)
  • Set up a dedicated MySQL user for the new database Virtualmin created

Installing selfoss

Update: In a very short space of time since writing this article, selfoss went through several updates and feature improvements. The current version is 2.6 and better than ever. You can download that straight from the official website.

Really quite simple:

  • Download the latest zip file from GitHub to the root directory of your new virtual web site: eg wget https://github.com/SSilence/selfoss/archive/master.zip. At the time of writing, version 2.2, which is the version that includes OPML import, is only available on GitHub, not on the main selfoss website.
  • Unzip: unzip master.zip
  • Move files into place: mv selfoss-master/* .; mv selfoss-master/.* .
  • Tidy up: rm -r master.zip selfoss-master
  • Set permissions as described on the selfoss website: chmod a+w data/cache data/favicons data/logs data/thumbnails data/sqlite public/
  • Edit config.ini. You’ll probably want to change db_type to mysql, and set db_database, db_username and db_password. You may also want to set username and password. You actually enter a hash of the password here, rather than the password in plain text. To generate this hash, browse to selfoss/password (e.g. http://myfeeds.fredbloggs.com/password)
  • You’ll most likely update feeds using a cron job. Every 30 minutes is enough for me, so I made an entry in /etc/crontab like this: 10,40 * * * * fredbloggs wget -O - -q -t 1 http://myfeeds.fredbloggs.com/update

Migrating from Google Reader

The first step is to export your existing RSS subscriptions from Google Reader. Proceed as follows:

  • Log into Google Takeout, Google’s data export service.
  • Ensure “Reader” is displayed and click “Create archive”
  • Click “Download”
  • You should receive a zip file that contains (amongst other things) your RSS subscriptions in an XML file called “subscriptions.xml”. Extract that file.
  • In version 2.2, at least, there’s no direct link to selfoss’s new OPML import page, so type /opml in your browser (e.g. http://myfeeds.fredbloggs.com/opml)
  • Upload the subscriptions.xml file
  • Click the “Update” link to force selfoss to commence loading your feeds.
  • Start whizzing through your RSS feed using the keyboard shortcuts >t< ("throw" - i.e. mark this item as read and open next item) and >r< (reload current view)

Be sure to add my RSS feed to selfoss for more great articles! http://pomeroy.me/feed/.

selfoss code and logo copyright © Tobias Zeising. All rights acknowledged.

Product Review: SoundWave SW100 Portable Bluetooth Speaker

As for many other people, my phone has become my go-to device for all my mobile entertainment needs. I currently have a Samsung Galaxy Note 2 (yeah, the one with the ludicrously large screen), so it’s great for anything from internet browsing to watching films in HD quality. I also use it as an MP3 player and for listening to podcasts and audiobooks.

I recently started looking around for a portable speaker that I could take on my occasional travels and, not to put too fine a point on it, use in the bathroom. Surely I’m not the only one that likes to listen to audio books while I shower?

The Note 2 isn’t, er, noted for its high quality speakers. Very few smartphone manufacturers have been able to complete with Apple on this front. But even the mighty built-in speakers of an iPhone struggle to compete with the noise of my geyser-like shower or electric shaver.

I’ll be honest, I’m a bit of a tightwad when it comes to my technology purchases, so I was looking for a device that could combine the impossible qualities of sound quality, power and cheapness. I wanted the convenience of connecting by Bluetooth, with the option of a 3.5mm socket for greater flexibility.

Having considered many products and read a lot of reviews, the device I settled for was this, the SoundWave SW100:

SoundWave SW100 Front

Here are some vital statistics:

  • Small – about three inches tall
  • Reasonably light – I haven’t put it on the scales, but it feels about the same weight as my Note 2 + case
  • Loud – I can’t find any official information on wattage, but when I turned it up to max in my small kitchen, it was louder than I could tolerate; at that point, there was some mild distortion
  • Built-in microphone – theoretically you can therefore use this device for conference calls; I have not tried this, but for the sound alone it can only be better than putting your phone into speaker mode
  • A claimed 10 hours music/talk time
  • A claimed 800 hours standby time – I’m not sure what use this figure is though; I’ll either be using it or charging it

Out of the box, the speaker was fully charged in less than an hour. It comes with a microUSB cable for this purpose. For my first trial, I took it into my company’s noisy server room. About 80% volume was sufficient to hear music clearly and without distortion, over the cacophony of fans and aircon.

It paired over Bluetooth without fuss. I have noticed the occasional blip when playing through Bluetooth, but I think this is more likely to be down to the phone (of which I demand a lot!) than to the speaker. In any event, you can use a 3.5mm audio cable (supplied) if you prefer.

The speaker has a non-slip base, great for most surfaces. The manufacturers have thoughtfully included an additional non-slip mat, making the speaker very unlikely to budge during normal usage. The non-slip mat also slightly neutralises the effect of resonance transmitted through the surface on which you place the speaker. Unless you’re an audiophile (I confess I’m not), this probably won’t mean a lot, but for some, it will be important.

SoundWave SW100 Back

For the size of the speaker, I was impressed by the bass response. In fact this was one of the reasons I bought the speaker – to improve bass experience, without having to lug around a sub woofer and without having to spend thousands on a high-end miniaturised speaker system.

Build quality is good. The case is mainly brushed aluminium, and not unattractive. It passed the spouse test; no exclamations of,”Oh how hideous! What horrendous technological monstrosity is that?!”

I paid £20 for the speaker. Although at one time it was available for less, it is still a bargain at this price. It receives favourable reviews (wherever you look) and I can only confirm what other reviewers are saying. Well worth the money, especially when you can consider you can pay four times the price for a product that may have a pretty label but is otherwise no better.


If you want a portable speaker, on the go, don’t mind that the output is mono, and don’t expect the sound to fill a concert hall, this is the device for you. Highly recommended.