#!/usr/bin/python
 
import pyinotify, pynotify
from subprocess import Popen
from os.path import expanduser
 
pynotify.init('Windows program notifier') # Not sure what this does
 
PATH = expanduser('~')
NAUGHTY_EXTENSIONS = ['exe','bat', 'com', 'dll', 'msi', 'ocx', 'reg', 'scr']
MESSAGE = "You just tried to download a Windows program. This is Linux. Bugger off!"
 
def notifyAndDelete(path, showNotification):
    """Delete any file with the forbben extensions."""
    if path.split('.')[-1].lower() in NAUGHTY_EXTENSIONS:
        print 'Deleting ' + path
        Popen(['rm', path])
        if showNotification == True:
            n = pynotify.Notification("Windows Program Fail", MESSAGE)
            n.show()
 
class HandleEvents(pyinotify.ProcessEvent):
    def process_IN_CREATE(self, event):
        notifyAndDelete(event.pathname, True)
    def process_IN_MOVED_TO(self, event):
        notifyAndDelete(event.pathname, False)
 
if __name__ == '__main__':
    wm = pyinotify.WatchManager()  # Watch Manager
    mask = pyinotify.IN_CREATE | pyinotify.IN_MOVED_TO  # watched events
 
    p = HandleEvents()
    notifier = pyinotify.Notifier(wm, p)
    wdd = wm.add_watch(PATH, mask, rec=True)
 
    notifier.loop()

When a user tries to download a program with an extension found in NAUGHTY_EXTENSIONS, They will get a Notify OSD popup informing them that they are not using Windows, and Windows programs won’t work on school computers. Of course, when I go to deploy this code, MESSAGE will be a little more appropriately worded.

This program is a combination of code I found from this pyinotify tutorial and a Notify OSD snippet I found in Acire.

Edit June 8 2010

Thanks to the anonymous commenter that pointed out the bug that allowed arbitrary code execution, and to Michael Hall for explaining it in more detail. The problem has been fixed.

If you run apt-cache search plymouth-theme, you’ll see which themes are available in the default repositories. This Youtube search has some videos of what is available. I chose the plymouth-theme-solar package, which has a nice solar flare animation. Next, run the following code, which I found here. Keep in mind that you need to change it to point to the plymouth theme you want to use.

sudo update-alternatives --install \
/lib/plymouth/themes/default.plymouth default.plymouth \
/lib/plymouth/themes/solar/solar.plymouth 100

(note: Line warping was only used to make it look pretty on a blog post.)

Next run sudo update-alternatives –config default.plymouth. You’ll see a numbered menu of the themes currently installed. Type the number for the one you want and hit enter. Finally, use sudo update-initramfs -u to apply your changes.

Here is the result:

There are not many themes available currently. However, once 10.04 is released and has been out for a little while, I think there will be many more options.

After reading up on the subject, I decided to give Synergy a try. Synergy lets you use use your keyboard and mouse on another computer over a network, just as if it was a second screen attached. Synergy looked promising, but several things about it did not work out for me.

Being a network application, Synergy consists of both a client app and a server app. It turns out that with Synergy the “server” is the computer with the keyboard and mouse you want to use on multiple machines. I’m sure this works fine for most people, but it does not make sense for my multimedia system. This computer will be on most of the time, being controlled by several different machines For my setup, the logical place for the “server” would be the multimedia system. I probably could have hacked it to make the client (running on my server) act more like a server, except each time the client app fails to connect to the server (running on my laptops), the time it waits for another connection increments.

When looking for Synergy alternatives, I found x2x. x2x is only designed for Linux, so it would not be usable for someone who needs to use a keyboard and mouse on multiple operating systems. I only use Ubuntu Linux at home, so this was not a problem for me. An advantage of x2x is that setup is very simple. First, install the x2x package (“x2x” in Ubuntu) on both machines, and openssh-server on the computer you want to control remotely. Then, from the computer with the keyboard and mouse you want to use on another system, run:

ssh -X user@server x2x -south -to :0

With this, you can now move your cursor beyond the bottom of your screen, onto the remote system. If you want to use a different edge of your screen, replace -south with -north, -east or -west. If you have key based authentication set up for ssh, you could stick this into the applications menu.

Updated 08 January 2010

It seems there is a bit of an issue with x2x in Ubuntu 9.10. Some people are seeing the following error when they try to run x2x:

No protocol specified

x2x - error: can not open display :0

To work around this issue until it is fixed, SSH into the box you want to remotely control, then run the following command:

xauth merge /var/run/gdm/auth-for-$USER-*/database

1. Use the package manager of your choice to install ia32-sun-java6-bin.
2. Download the Android SDK for Linux, then extract the zip file.
3. In the SDK tools folder, open up the ddms file in your favorite text editor.
4. Modify line #72 to the following: java_cmd=”/usr/lib/jvm/ia32-java-6-sun/bin/java”

Here are the screenshots I took:

As you can see, I’m running a clone of the theme on HTC’s Hero Android phone. This theme can be downloaded here. All the install took was downloading the theme, putting it on my phone’s SD card as update.zip, booting into recovery mode and flashing the update. Of course, you’ll need a rooted G1 for this to work. I’m running JesusFreke’s wonderful 1.5 build. Read this guide for instructions for rooting your G1.

Below I have the configurations and prices for four machines: an Apple Mac Pro, a Dell XPS 630, The Wild Dog performance desktop from System76, and finally a custom built machine with parts from Newegg (thanks to excid3 for the build specs). Though the machines are from four different OEMs (aka companies that build computers), I configured each to be as close as possible in specifications and performance.

Apple Mac Pro, $2,849.00

• Processor: One 2.66GHz Quad-Core Intel Xeon
• RAM: 8GB (4x2GB)
• Hard drive: 1TB 7200-rpm Serial ATA 3Gb
• Graphics card: NVIDIA GeForce GT 120 512MB
• DVD burner: One 18x SuperDrive

Dell XPS 630, $1,679

• Processor: Intel® Core™2 Q9550 (12MB,2.83GHz, 1333FSB) (Also a quad core)
• RAM: 8GB Dual Channel DDR2 SDRAM at 800MHz (4 DIMM)
• Hard drive: 1TB Performance RAID 0 (2 x 500GB SATA 3Gb/s 7200 RPM HDDs)
• Graphics card: SLi, Dual nVidia GeForce 9800GT 512MB
• DVD burner: 16X CD/DVD burner (DVD+/-RW) w/double layer write capability

System76 Wild Dog Performance Desktop, $1,089.00

• Processor: Quad Core Q6600 2.40 GHz FSB 1066 MHz L2 8 MB
• RAM: 8 GB – 4 x 2 GB – DDR3 – 1333 MHz
• Hard Drive:  1 TB SATA II 300Mbps – 7200 rpm 32 MB Buffer
• Graphics card: 512 MB ATI Radeon 4550 PCI-Express x16 GDDR3 (DVI, VGA, S-Video, DVI to HDMI, DVI to VGA)
• DVD burner: CD-RW / DVD-RW

Custom built machine, $608.90

Note: If you wanted Windows Vista on this machine (not recommended), just add $179.99 to the price. Also, the links to all the parts are listed below, seeing as there is a lot more customization that goes into a custom build.

• AMD Phenom 9600 Agena 2.3GHz Socket AM2+ 95W Quad-Core Processor Model HD960ZWCGDBOX – Retail
• Kingston HyperX 2GB 240-Pin DDR2 SDRAM DDR2 1066 Desktop Memory Model KHX8500D2/2G – Retail (x4)
• Antec earthwatts EA500 500W Continuous Power ATX12V v2.0 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC Power … – Retail
• ASUS M4N78 Pro AM3/AM2+/AM2 NVIDIA GeForce 8300 HDMI ATX AMD Motherboard – Retail
• Western Digital Caviar Black WD1001FALS 1TB 7200 RPM SATA 3.0Gb/s 3.5″ Hard Drive – OEM
• NZXT HUSH Black SECC Steel/ Aluminum/ Plastic ATX Mid Tower Computer Case – Retail
• PLEXTOR 20X DVD Super Multi Qflix Drive Black SATA Model PX-806SA SW – Retail

Biased Summary

I’ll start off with the most obvious and least controversial conclusion: you’d be crazy not to get a custom built machine. Due to the geeky tendencies of this blog, most people reading this are likely to be fellow geeks. Any geek worth their weight in old CRT monitors can put that machine together. If however you are not a geek, surely you know someone who is. For $200 and a few hours to play with all the shiny parts, any geek would be glad to put this machine together for you, and you’d still be saving a huge amount of money.

Now for the slightly more controversial conclusions. I believe that a higher price does play a role in a person’s decision to buy a Mac. It is certainly not the only factor, since as far as OEM equipment goes, Apple is fairly nice. I agree that Apple has some very high quality hardware. However, the hardware in each of these machines is very similar, and all high quality, and yet the Apple machine is $1,170 more expensive than the second most expensive and yet very similar machine. You could even get any one of these machines and put OSX on it yourself if Apple would let you (or you felt like using The Pirate Bay).

Given the fact that all four machines are very similar, lets assume for a moment that the custom built machine represents the price each manufacturer pays to build their computer (not quite accurate, as the OEM’s save money by buying parts in bulk). This would mean that what you are really buying from an OEM is the convenience of having someone else put a computer together for you. That convenience costs you $2,240 if Apple builds it and $1,070 if Dell builds it. The lowest OEM service price is from System76, at $480, which is just over twice my recommended build price from the friendly neighborhood geek.

My numbers are certianly not perfect, especially since it is impossible to get an exactly identical machine from two OEMs. However, even after doing tweaking for any innacuracies in my calculations or configurations, I think your findings will be the same: all OEMs are expensive, but Apple is by far the most expensive.

I have 9.04 installed on my Inspiron 1420, using the ext4 filesystem (also quite stable in my experience), with noatime set in /etc/fstab. My CPU is an Intel Core 2 Duo clocked at 1.5 GHz, 4GB of ram and a very average 80GB SATA hard drive.

Profiling a boot with bootchart was as simple as “sudo apt-get install bootchart”. With that done, I just rebooted my machine. Once I was back up, there was a .png file in /var/log/bootchart containing the details of my boot process.

Boot time == 20.27 seconds!

And now for the gory details…

Translations / Tutorials In Other Languages:

• Espanol
• Bengali

Though in most North American cities one cannot find a spot without at least a weak WiFi signal, many of us Linux geeks still live in rural areas with less Internet connectivity. Also, in various non-Westernized nations, there is a growing number of Linux users who may have a computer at home, but cannot afford a decent connection. For both groups, software updates typically demand an Internet connection, which can make updating difficult if not impossible. There is now a solution though, a new program called Keryx.

Keryx was written by Southern Illinois University computer science student Chris Oliver, who wanted a way  to download software and updates for Ubuntu systems that had little or no connectivity. Simply put Keryx on your pen drive, use it to create a new project file which retains a copy of your software sources and other system details, then take the pen drive to a computer with a better connection. Via it’s Synaptic like interface, users can then select all updates for download, plus select any other software they may want to install, complete with dependency resolution.

Because it is written in Python, and utilizes wxWidgets for it’s interface, Keryx can run on Linux, OSX and Windows. Pre-compiled binaries for Windows are included in the download (meaning you don’t need to install Python and wxWidgets first), and similar binaries for OSX and Linux are in the development road-map, along with Debian/Ubuntu packages.

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This tutorial will walk you through the simple process of using Keryx to get updates and new software. Keryx currently only works for Debian based distros, but there are plans for adding support for a number of other package management systems. The system being updated is running Ubuntu 8.10, with no network connectivity. The system that will be grabbing the updates is running Windows XP, though it could just as easily be Windows 95 through Vista, OSX, or another Linux box.

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Go to the Keryx website and click the download link. Once the download is complete, put it on a USB pen drive that has a decent amount of free space, and unzip it.

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Keryx uses wxWidgets for it’s graphical interface, and a default Ubuntu install does not have wxWidgets installed. Therefore you must create your project file in a terminal window. Fear not, as it is really quite quick and painless.

Simply open up your terminal, and then navigate into the “linux” directory inside the Keryx folder. On my computer this was “/media/disk/keryx/linux” but it will look a little different for you, depending upon what your pen drive is called. Once you are in that directory, enter in the following, making sure to replace <project> for whatever you want to call your project and <plugin> for they type of system you are updating, in this case debian.

python keryx.py –create <project> <plugin>

note: the above is two dashes, but my font makes it look like one.

In a few moments the project will be made. When this happens, close out of the terminal and safely remove your pen drive, to take to another computer.

Note: For some people, Keryx may experience difficulty fetching the package list files in the next step, if their repository mirror is set to the regional default. If you experience this, consider selecting a different mirror in System/Administration/Software_Sources and then repeating step #2.

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In this tutorial I am using a computer running Windows XP as the computer with a high speed connection. However, this could just as easily be done on any Linux or OSX computer, so long as they both had Python and wxWidgets installed.

On your Windows computer, plug in the pen drive and open up the Keryx folder. In this folder you will see a “win32″ folder containing prepackaged binaries for Keryx. Using these you can run Keryx without having to first install Python and wxWidgets, making Keryx a very portable application. The file you need to run is called “keryx.exe,” though Windows may hide the .exe part from you. When Keryx opens, click “Open Project” and find the project file you created a few minutes ago.

When you open Keryx, go ahead and let it download the latest package list.

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Once the package lists have been downloaded, you’ll see the full Synaptic-like package list in Keryx. This list can be sorted by package name, status (not installed, installed, needs updating, etc.), etc. The first thing you’ll want to do is click “Get Updates” near the top of the window.

When I started the download, Keryx had 210 files to download. Your number will vary, but you are likely to have a lot of updates if you have a fresh install. Keryx will tell you when it is finished, so you might want to go get some coffee.

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You probably want to be able to install wxWidgets on your Ubuntu system, so that you can run the Keryx graphical interface on it. Near the top of the window, start typing “wxversion” in the search field. Because the Keryx package search tool is so amazingly fast, you’ll only need to type the first few letters before you see python-wxversion. Right-click this package and then click download. It has several dependencies that Keryx will tell you about, so go ahead and let the program download those as well.

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With all your packages downloaded, close Keryx, safely remove your pen drive, and go back to your Ubuntu machine. When you plug the pen drive back into your Ubuntu machine, you’ll notice that the package are stored in projects/<project>/packages (where <project> is the name you gave the project). You’ll need to open up your terminal again, and navigate to this directory. Once there, run the following:

sudo dpkg -i –force-depends *.deb

This line will install and/or update all the packages in that directory. The “force-depends” parameter is necessary in this case, as we are installing the wxWidgets packages, which have a circular dependency. Without this parameter, dpkg will start whining at you. If you have as many packages as I had, this may take a while. Go refill your coffee, and by the time you get back, the install might be done. Thats all there is to it!

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Despite already being a rather useful tool, there are a lot of enhancements planed for the near future with Keryx. Most of it’s features, including it’s package management support, are implemented via a very flexible plugin infrastructure. So if you are a Python hacker and would like to help implement some of the new features, or have some ideas of your own, feel free to check out the code and dive in!

If you run into any problems using Keryx, or would like to report a bug, check out the friendly forums.

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• Support for more distributions, such as Fedora, Red Hat, Mandriva et al.
• Package management like support for downloading and installing useful Open Source Windows software.
• Built-in installation of downloaded packages, so the user need not mess with the CLI
• Pre-compiled self contained binaries for Linux and OSX (like what already exists in the win32 folder), so that no matter what OS a user is running, they will be able to simply plug in their USB drive and run the graphical interface.
• Improved documentation