san-ho-zay

"It is a very sad thing that nowadays there is so little useless information" - Oscar Wilde

[san-ho-zay]

Precisely ...

For the past two months I've been using Fedora with Gnome Shell and it's been great to get used to it as an interface and to become familiar with another distribution. It was like being back at home really because, prior to running Ubuntu, I'd been a RedHat user for several years. Not RHEL, but the old Red Hat Linux that existed before Red Hat went commercial.

Fedora certainly did the job for me and, apart from a few broken packages here and there, I didn't have any problems with it. I think I always knew I would come back to Ubuntu when the final beta of 12.04 Precise Pangolin was released.

Again, an environment I'm very familiar with but one that's now much more polished than the early days of 11.04 Natty Narwhal. It's amazing how far Unity has come on in just a year -- or 18 months if you include the 6 month development cycle for that release.

Surprisingly for this long-term support release, Ubuntu adds a new feature -- the heads-up display or HUD.

I believe the long-term view is that this will replace menus. I'm not so sure about that, but it's certainly useful. The idea is you hit the alt key, type a few characters and it will search the menus to give you a list of options you can access with keyboard or mouse.

But it's actually more sophisticated than that description. It does fuzzy matching and also likely matches in other applications. If you look at the screenshot, I opened the gedit text editor, hit the alt key and typed "print". Not surprisingly, it comes up with File-Print and File Print-Preview. The third option though, is the printer setup from system settings, which is feasibly something I'd want if I wanted to do some printing.

Things start to get much more interesting when you try it on your web browser. It will search menus but, because web browsers expose all sorts of things as menus, this can also mean recent tabs, history and bookmarks. It gives the browser a whole new dimension. All those bookmarks I have deeply nested in sub-menus suddenly become accessible again. It also picks up on RSS feeds if you use something like Firefox's live bookmarks so it will pick up on the latest stories you are interested in.

It's going to take some practice to get used to using it, but it looks like a great feature.

[kaiserlowen]

So I’ve been wanting to program a calculator in Java just to say that I could do it, and it works, except for my if() statements. THEY WON’T FREAKING WORK. So I’m gonna get one of the upperclassman to help me with it, see if they can figure it out.

if( input3 == “add”)

{

...

[san-ho-zay]

You need input3.equals("add") or, if you want to avoid testing for null, "add".equals(input3). The == operator tests if two objects are the same object, not if they have the same content.

[san-ho-zay]

Thinking in Python

I'm no expert with Python, but I'm enjoying learning it and using it. After what feels like a lifetime of C and Java (and more recently Objective-C), I've finally managed to wean myself off adding a semicolon to the end of every line of code. But's there's more to being Pythonic than that. I still think in C and Java and here's an example of how:

I've been writing an application in Python with GTK3 and I wanted to take a block of text and normalize the indentation, i.e. preserve its indentation but take the least indented column back to column zero.

The C and Java half of my brain kicked in, it got mangled into Python, and this came out:

def common_indent(text): common = -1 for line in text.splitlines(): line_indent = indent(line) if line_indent == 0: return 0 if common < 0 or line_indent < common: common = line_indent return common

Only when I got it working did the Python half of my brain catch up and refactor it into this:

def common_indent(text): return min([indent(line) for line in text.splitlines()])

Which, apart from being easier to type I think is a lot easier to read. It's hardly worth writing it as a function any more!

So I'm finding there's more to Python than learning the language. It's also a matter of changing the thought process, at least for programmers used to the brace languages. Moving the other way -- from Python to C, Java, C++ or C#, must feel like climbing a mountain.

[san-ho-zay]

Using libnotify with Python and GTK3

Now that PyGTK is on it's way out and the Gnome world is thinking GTK3, some old ways of doing things don't work any more. On-screen notifications using pynotify for example. I hunted around for a long time before I figured this out, but here is how to use the underlying libnotify with Python and GTK3:

from gi.repository import Notify Notify.init('My Application Name') notification = Notify.Notification.new( 'Test', 'Test notification', 'dialog-information' ) notification.show()

Easy when you know how.

[san-ho-zay]

Long time no post

Well, it's been over six months since I've managed to post to this blog. From August I got very busy working on a new iPhone/iPad training course and that took up most of my time until Christmas. Looking back, it was a bit like a prison sentence! So there's a shiny iMac on my desktop and Ubuntu sat largely disregarded as 11.10 Oneiric Ocelot came and went. When I did get round to upgrading I found myself drawn to Gnome Shell. Which is a surprise because I actually liked Unity. But a combination of problems getting Java development tools installed (Netbeans and Eclipse), Canonical's flicking between default applications (Thunderbird and Evolution) and perhaps a desire for pastures new led me to ...

Fedora! It was a remarkably swift process. My laptop needed a tidy up and upgrade. I had an impulse to try a Fedora Live USB before I installed Oneric. Liked it. Did the install and spent a few hours setting it up. Then took the plunge and put it on my desktop PC as well. Don't get me wrong, I still like Ubuntu but I'm enjoying exploring Fedora. It feels lighter and much closer to a pure Gnome experience. Touch wood, I've not had any major issues so far. It's been a fairly painless transition. The package manager isn't as slick as Ubuntu's software centre or Synaptic. I use yum mostly, but then again I used to use apt-get a lot too. Fonts looked awful, but a few tweaks got the same settings as Ubuntu - and I installed the Ubuntu font too.

Faenza and Faenza Cupertino icons to match the blueness of it all (was that a subconscious nod to the iMac next door?).

My main issue is finding a decent Twitter client. Gwibber is OK but I always thought it was a bit heavyweight for what it does. Turpial didn't inspire me. Maybe I'll just stick to using my Apple devices for Twitter, although I do like seeing the notifications as I am working. Eclipse and Netbeans were easy to set up, which is just as well as I have some Java work to do over the next month. So we'll see how it goes. Maybe I'll get bored with blue and revert back to purple and orange come April/May when the LTS release of Ubuntu comes out?

[san-ho-zay]

Checking whether a window is maximized in PyGTK

I've been writing an application using PyGTK recently and one of the things I wanted to do was save the window state on exit (size and whether maximized) so that I can restore the next time the application runs.

Checking whether the window is maximized proved to be more difficult than I expected and the PyGTK documentation and web searches didn't turn up a direct answer.

The PyGTK documentation for gtk.Window suggests that the window-state-event on the gtk.Widget is the way to go but my first attempts didn't work. I always got a widget gtkStateType of gtk.STATE_NORMAL, regardless of whether the window was maximized.

The solution is actually quite simple. Simple to do anyway, but more difficult to explain: The window state is associated with the underlying gtk.gdk.Window, not the gtk.Window widget that triggers the window-state-event. Calling get_state() on the gtk.Window is simply calling get_state() on its superclass gtk.Widget. Hence the widget state of gtk.STATE_NORMAL. To get the underlying gtk.gdk.Window you need to use the get_window() method of gtk.Widget (of which gtk.Window is a subclass) and then call get_state(). In the event handler for the window-state-event, the gtk.Window is passed through as the widget parameter (but you could also call get_window() on your gtk.Window directly):

import gtk class WindowState(gtk.Window): def __init__(self): super(WindowState, self).__init__() self.connect("destroy", gtk.main_quit) self.set_size_request(800, 600) self.connect("window-state-event", self.on_window_state_event) self.show() def on_window_state_event(self, widget, event, data=None): mask = gtk.gdk.WINDOW_STATE_MAXIMIZED maximized = widget.get_window().get_state() & mask == mask print maximized WindowState() gtk.main()

This works as I wanted, printing True when the window is maximized and False when unmaximized.

[san-ho-zay]

I've been teaching myself Python over the last couple of weeks and exploring GUI options to go with it. I always seem to end up writing text editors to check out GUI toolkits and I have more unfinished versions than I know what to do with ... ... but I like this one!

[san-ho-zay]

Déjà Dup - Part 2

OK, so I've got my initial backup sitting pretty on my spare drive. Let's have a play ...

Is it incremental?

Of course it is! The first thing I tried was another backup straight away. As expected, this runs much quicker, just backing up differences. The scan process still takes some time but the actual backing up was over in a flash.

Files created

$ ls -sk total 2619292 24 duplicity-full.20110530T084823Z.manifest 30712 duplicity-full.20110530T084823Z.vol10.difftar.gz 30728 duplicity-full.20110530T084823Z.vol11.difftar.gz 30716 duplicity-full.20110530T084823Z.vol12.difftar.gz ... (for brevity, I've cut a lot of similar files from here). 16232 duplicity-full.20110530T084823Z.vol84.difftar.gz 30720 duplicity-full.20110530T084823Z.vol8.difftar.gz 30720 duplicity-full.20110530T084823Z.vol9.difftar.gz 50400 duplicity-full-signatures.20110530T084823Z.sigtar.gz 4 duplicity-inc.20110530T084823Z.to.20110530T092615Z.manifest 1972 duplicity-inc.20110530T084823Z.to.20110530T092615Z.vol1.difftar.gz 1008 duplicity-new-signatures.20110530T084823Z.to.20110530T092615Z.sigtar.gz

So a pile of evenly-sized (30MB) compressed files.

Perhaps a slight downside and a price to be paid for convenience is that the files are fairly unintelligible and it wouldn't be a simple task to restore anything without the help of Déjà Dup. I'd already read about this and half expected the files to be completely unreadable but they can be opened with FileRoller and browsed. It's just not simple to find a specific file in the haystack of archives.

This doesn't worry me too much to be honest, especially if the tool ships as standard in 11.10.

Restoring

Before I ran the second backup, I made a directory in my Public folder called Test and created a text file in it. Then ... oops, I deleted it. Let's see if I can get the directory back.

My first thought was to use the restore button in Déjà Dup:

It offers me a selection of backup dates, which is good and I selected the latest:

Yes, I want to restore the files to their original location:

I was rather hoping to select which files I wanted to restore at this point, but this option appears to only restore the whole backup. This is not what I wanted, so I cancelled from here, but you can see how easy it is to do a full restore.

Restoring Individual Files

To restore individual files and folders, you need to use the extension that Déjà Dup adds to Nautilus:

It then scans the backups looking for any files that have been deleted:

Once it's finished, select the file to restore, hit restore, confirm and the file comes back. Pretty good. The Nautilus extension also allows you to go back to a previous version using the backups you have.

Conclusion

All in all a great little backup tool. It doesn't have all the options, e.g. selecting when to run daily or weekly backups, but the simplicity is refreshing in an application that undertakes a task that most of of just want to work without thinking too much about.

I look forward to seeing it in 11.10.

[san-ho-zay]

Déjà Dup - Part 1

Déjà Dup has been proposed for inclusion in the next Ubuntu distribution, space permitting and, as I have a spare disk sitting around (sitting around in my desktop PC in fact), I thought I'd give it a whirl ...

I understand that the version that will be included in Ubuntu 11.10 will be a new Gnome 3 version - the version I'm trying here is the standard offering as it stands in the 11.04 repositories. For reference, this is version 18.1.1.

Creating a Backup

Opening screens don't come much simpler than this one:

I'll leave you to work out which button I pressed to start creating a backup! The next page in the wizard allows you to select a backup location, which has a range of options including cloud backup solutions, local drives and network locations (SSH, FTP, etc.). You also have the option of encrypting the backup.

You can choose what you exclude from the backup. Wastebasket and Downloads are the default exclusions.

A brief and to the point summary ...

... and off it goes:

The Resume Later button allows you to pause the backup. It closes the backup window and you can pick up where it left off when you restart the application and press the backup button.

At this point, I remembered several directories that I didn't really want to back up. So I decided to cancel and start again. Oops! I think I made the wizard drop his wand. Clicking on the backup button again didn't take me back through the steps of reconfiguring my backup. Instead it seemed to think I wanted to back up my files to the Amazon S3 cloud backup service.

A search in the Unity Dash revealed that there is a Déjà Dup Backup Preferences application, which allowed me to set things up as I had in the wizard, or I could have just selected Edit -> Preferences from the tool itself. So just a slight hiccup. I pressed the backup button and off it went ... again.

Minimizing the backup application leaves the icon in the Unity launcher with a helpful progress bar:

The progress bar didn't move for quite a while during the "scan" phase of the backup, and then started to progress as files were backed up. I do realise that progress bars are hard to do well but this is aiming to be a super-simple user tool and there will inevitably be a moment of doubt whether it is working. Several moments if you have a lot of files.

When the backup finishes, it gives you the option of repeating on a regular basis:

In part two, I'll have a look at what this backup process actually created, "accidentally" delete a file and see how the restore process works out. It's certainly created a good impression with me so far.

[san-ho-zay]

Tuning the Grid plugin in Unity

The Compiz Grid plugin as configured with the Ubuntu Unity desktop provides similar resizing shortcuts to the Snap feature in Windows 7. Perhaps it's gimmicky, perhaps it's useful? But when it happens when you don't want it to, it's just annoying.

I often put windows in the top left corner of my screen, but I was finding the Grid plugin was interpreting that to mean that I wanted to maximise the window. Irritated, I went into the plugin configuration and turned the top edge binding off.

However, I have since found a better way ...

In the settings for the Grid plugin in Compiz Config Settings Manager (CCSM), there are a series of thresholds that you can set for the way the Grid plugin interacts with screen edges. I initially found the settings counter-intuitive - I tried increasing the thresholds to reduce the sensitivity but this just makes it worse. It's not how far you have to push, it's an invisible margin in which windows will snap. Zero disables the feature, so a value of 1 requires the most positive movement to have it work.

With the threshold set to 1 on the top edge, it's much more usable now. I can put windows at the top of the screen without any problems, but if I give them a definite shove they maximise.

[san-ho-zay]

Command line quickie: Check disk space used by sub-directories

Find the top 5 items (sub-directories or files) by total disk space used, in MB:

$ du -sm * | sort -rn | head -5 539 drivers 166 arch 102 fs 87 net 57 sound

This gets a disk usage (du) summary (-s), in megabytes (-m) for all items in the current directory (*), then passes that for sorting (sort), which sorts numerically (-n), in reverse order (-r) and we print out the first 5 lines (head -5).

That's the simple version, and may suffice in a lot of cases, but it doesn't account for hidden files and directories. In this example (the Linux kernel source tree), hidden items are significant:

$ du -sm .[!.]* * | sort -rn | head -5 539 drivers 493 .git 166 arch 102 fs 87 net

The du (disk usage) command doesn't offer an inbuilt solution to hidden files, so we have to use the shell to tell du what we want. Hence the odd-looking construct with the square bracket. Consider what happens if we try without:

$ du -sm .* * | sort -rn | head -5 1642 .. 1642 . 539 drivers 493 .git 166 arch

The problem is that the current directory '.' and the parent '..' are both shown. The pattern '.*' means a dot followed by anything else (including null).

The key to the solution is that '[!.]' means any character that's not a dot, but it can't be null. So we end up with '.[!.]*', which means a dot, followed by anything that's not a dot (but not null), followed by anything (including null).

On GNOME-based Linux distrubutions, "Disk Usage Analyzer" provides an interactive, graphical equivalent of the above, but being able to achieve the same result with the command line is sometimes useful, e.g. recovering a broken system that ran short on disk space, or on a server.

[san-ho-zay]

Lubuntu vs Xubuntu - In conclusion

I've been looking at Lubuntu and Xubuntu this week and it's time to shut down those virtual machines and sum up. This was never going to be a competition - I think both have their place - but I think Lubuntu has raised the bar and that can only be a good thing.

The memory footprint of Lubuntu is a major plus point where older PCs are involved. I've been running both distributions perfectly well in 512MB but Lubuntu still has memory left over for caching which should keep it snappy. Pretty good on disk space too, at just 1.6G. You could even make a case for installing the Lubuntu desktop for occasional use on a server machine - it's so lightweight.

Both distributions can be configured to produce a layout that suits, although maybe not exactly what you had in mind. If you are into your desktop effects, both will clearly fall short without significant changes, but you should still be able to get either set up to work productively. Xubuntu is more mature and gives you more options if you are used to an Ubuntu desktop but out-of-the-box Lubuntu is going to feel very familiar to legacy MS Windows users. It's clean lines and simple approach should make for an easy transition from a failed XP machine or similar.

Xubuntu edges out Lubuntu in terms of functionality in its default applications (particularly gmusicbrowser and Gimp) but most of the Lubuntu applications will be perfectly usable. Simplicity can be a bonus and you can always install others when you need them.

I liked Xubuntu when I was running it as my main desktop and I still do. It's improved quite a bit since then and it's still a nice environment to work in. But I'm very impressed with what the Lubuntu team have achieved. The simplicity is refreshing and that memory footprint is fantastic.

So will I be switching to either when 11.10 comes along? Well, no ... I do actually find Unity a productive environment to work in and I've missed having the super key to bring up the Dash in those VMs! But it's been fun trying them out and I think I'd manage working with either if I had to. It will be interesting to see how things develop between now and October. I'm sure some people will end up turning their back on Unity (and Gnome Shell) in favour of one of these and I think they'll be well served.

[san-ho-zay]

Article from LinuxUser & Developer magazine: "To help us celebrate the 100th issue of Linux User & Developer, Ubuntu founder, Mark Shuttleworth, agreed to take the reins from our regular Ubuntu columnist (Dave Walker) and take us through why he believes it was the right decision for Ubuntu to embrace the future with Unity… "

[san-ho-zay]

Lubuntu vs Xubuntu - Part 4

So far this week, I've looked at installation, the default desktop and the default applications. In this post, I'll consider what can be done in terms of customising the layout of the desktop with out-of-the-box options.

Customisation

Everyone will have different objectives with customisation, so the best generic test I could think up was to re-arrange the desktop to mimic an "Ubuntu Classic" desktop, with top and bottom panels, menu, and so on. With Gnome having set their sights on Gnome Shell, and some Ubuntu users threatening to jump ship because 11.10 will only provide Unity, emulating the classic Gnome 2 desktop could be a common objective.

Lubuntu

This was reasonably straightforward. It was easy to create a new panel. Editing, while different from editing GNOME panels, is as simple if not simpler. The only thing that caught me out slightly was a couple of applets (the shutdown and system tray applets) that you can only have one of. So if you have one of those in one panel it doesn't appear in the list of items for the other.

In the top panel, the menu isn't quite the same as a GNOME desktop but it does the same job. The first icon gives the applications menu (which includes System and Preferences) and the second gives a places menu. The latter doesn't work quite as smoothly as the Nautilus places menu (it offers the choice of opening in a terminal or in file manager instead of just going to file manager), but it's OK. Then comes a list of application shortcuts. Over on the right side we have the system tray, the date and shutdown button.

The bottom panel has the show desktop shortcut, the taskbar and the window switcher. Window switcher set to manage four workspaces. There is no applet for the trash/wastebasket - that was the only part of the standard GNOME 2.x setup that I couldn't replicate.

The configuration of the time gets a mark down with Lubuntu, simply because the dialog suggests running "man 3 strftime" in a terminal to find the placeholders for date elements!

I changed the wallpaper but the fonts were already set to the Ubuntu font. I left the colours and window decorations as they were because the other options weren't that great, although I did change the colour of the panels to an Ambiance-like hue.

Assuming anyone making a switch from 10.10 or 11.04 will have got used to window controls on the left by now, I also made that part of the customisation task.

Xubuntu

Most of the top panel was already similar to Ubuntu Classic, so it was just a matter of making a new panel at the bottom and shifting things around. I was able to make the applications menu icon and text, but I could only make the places menu an icon. Everything else was available to add to the panel (including the trash/wastebasket).

As with Lubuntu, I changed the wallpaper. I also switched fonts to the Ubuntu font. The alternatives for window decoration are more attractive with XFCE/Xubuntu so I changed to a different style in this case. Window buttons moved over to the left and job done!

Overall

So quite reasonable customisation of these desktops is possible, although you might not be able to get exactly what you want. I think Xubuntu provides the better options for configuration overall. Not just because it was closer to Ubuntu Classic to start with, but also because it does have more options and a richer palette of applets and decorations to choose from. If disenchanted Ubuntu users do turn to Lubuntu as a way to keep their panels, I think they could be frustrated.

Note that I've stuck with out of the box configuration but there's no reason why you couldn't add a dock to one of these desktops. You'd just have to be careful of dependencies if you were aiming for a lightweight environment.

If you are inspired (or you think I've not done a very good job), why not fire up VirtualBox and see if you can do a more comprehensive re-configuration of these desktops?

[san-ho-zay]

When I look at GNOME [3] though, what I see is change just for the sake of change, not change for greater end-user usability.

Steven J. Vaughan-Nichols

ZDNet.com - Fedora 15's five best features

[san-ho-zay]

Lubuntu vs Xubuntu - Part 3

In part 3 of this series, I'm going to look at the default applications that come with Lubuntu and Xubuntu. Obviously you can install others but your choices could be limited by the lightweight desktop ethos and dependencies on the ubuntu-desktop package.

Default Applications

These are the default shipped applications for the most common tasks (yes, I probably forgot something that you depend on):

ApplicationLubuntuXubuntuWeb BrowserChromiumFirefoxEMail ClientSylpheedThunderbirdChat ClientPidginPidginTerminalLXTerminalTerminal (xfce)Text EditorLeafpadMousepadWord ProcessorAbiwordAbiwordSpreadsheetGnumericGnumericImage EditormtPaintGimpMusic PlayerAudaciousgmusicbrowserMedia PlayerGNOME Media PlayerParole Media PlayerFile ManagerPCManFMThunarDevelopmentPythonPython, gcc

Neither distribution finds room for Java or a social media client like Pino/Gwibber. There's no Ubuntu One and no Zeitgeist in these lightweight environments either. Xubuntu has the software centre and Lubuntu doesn't but I imagine that it would be under consideration for 11.10 now it's "official".

The options in Xubuntu are well known and well respected applications which will probably do the job for most in terms of functionality, albeit with a little less gloss than full-blown Ubuntu. The gmusicbrowser application is a Rhythmbox/Banshee-like application, integrated with the notification area:

Thunar has been the file manager in Xubuntu since I was last using it in the 2009 releases and it works well (apart from it not managing the desktop icons):

Chromium is deservedly popular, even on Ubuntu so no complaints about its inclusion in Lubuntu. I'd never heard of Sylpheed, mtPaint and PCManFM but they all look like decent applications. Obviously simpler than the Xubuntu equivalents but surprisingly well-featured. A special mention must go to the Sylpheed email client, which I set up with my Gmail account in seconds simply by entering my name and email address into the splash dialog that appears. Take note Evolution and Thunderbird.

My main doubt about Sylpheed is the address book, which I couldn't find a way of linking to the address book in my Gmail account. The other things all seem to be there though - spam filtering with BogoFilter, message filters, signing/encryption.

mtPaint reminds me a little of Linux applications of ten years ago. Good on functionality (layers, resizing options, sharpen, blur, etc.), but looks a bit ragged and inconsistent with everything else. It has plenty of options though and would handle a lot of common photo and image processing tasks. There's no separate screenshot program in Lubuntu by the way, screenshots are taken (including the ones in this sub-section) using mtPaint.

The PCManFM file manager is a pleasure to use. Simple, responsive and manages your files. What more could you ask of a file manager?

Overall

So, after just a brief look, no major worries about the shipped applications with either distribution. I think I'd be content using most of them. As you'd expect from the lower memory and disk footprints, the Lubuntu set are simpler, in some cases rougher, and may fall short of expectations for some. Having said that the low memory footprint of everything else on Lubuntu would probably allow a couple of "luxuries" on low-spec machines.

[san-ho-zay]

Lubuntu vs Xubuntu - Part 1

I spent some time yesterday installing Lubuntu and Xubuntu in identical VMs. Over the next few days I'm going to take a look at the similarities and differences between the two. I'll be looking specifically at installation, the desktop, the applications and out-of-the-box customisation options.

Installation

Each desktop installer uses Ubiquity and the two installation sequences were identical as far as I could tell. Visually I think Lubuntu has a slight edge, with the splash screens looking marginally more polished and professional.

Timings and Footprint

Installations were made in VirtualBox OSE on a modern machine with 4GB RAM and a quad core processor. As such, installation timings are for comparison rather than an indication of the time it would take on an older PC. I allocated 512MB memory and 1 processor to each virtual machine for the installation.

DistributionInstall Time (mm:ss)Boot Time (s)ISO Size (M)Disk (G)Memory (M)Lubuntu10:1627680.31.6213 / 321Xubuntu11:2230687.82.2408 / 586

To measure the memory footprints (base/loaded), I temporarily gave both VMs plenty of elbow room (1.5G). The base was measured by loading up a terminal immediately after booting and running free -mo. Loaded footprint was measured the same way with a "typical" set of the default applications running - web browser, email client, word processor, terminal and file manager.

As you can see, Lubuntu lives up to its billing as a truly lightweight distribution, coming in at a shade over half of Xubuntu's memory footprint in both my base and loaded tests. Lubuntu was also more miserly than Xubuntu in terms of disk space used, with 1.6G compared to 2.2G for a vanilla install.