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22
Aug 10

Gitolite: Does Not Appear to be a Git Repository

Have a user, whose public key was successfully added under “gitolite-admin/keydir” and whose rights were successfully configured under “gitolite-admin/conf/gitolite.conf”.

When this very user is cloning an existing, correctly configured repository, his/her identity ( public key ) is not being passed correclty => hence notice a password prompt:

$ git clone git@yourgitserver.com:your-project
Cloning into your-project...
git@yourgitserver.com's password: 
fatal: 'your=project' does not appear to be a git repository
fatal: The remote end hung up unexpectedly

Here is the way to help out git / gitolite to understand which identity ( public key ) to use:

$ vi ~/.ssh/config
host gitolite
     user git
     hostname yourgitserver.com
     identityfile ~/.ssh/mypubkey

Now changing “git@yourgitserver.com” to “gitolite” does the trick:

$ git clone gitolite:your-project
Cloning into your-project...
remote: Counting objects: 83, done.
remote: Compressing objects: 100% (77/77), done.
remote: Total 83 (delta 3), reused 0 (delta 0)
Receiving objects: 100% (83/83), 156.45 KiB | 49 KiB/s, done.
Resolving deltas: 100% (3/3), done.

Notice, public key was successfully accepted => hence there was no password prompt, and the clone was successful.


21
Aug 10

Making Git to Add Empty Directories

Since git is a “content” based SCM, and empty directories by git are not considered to be content [ which is arguable ], the only way to add them is to add “.gitignore” to every empty directory.

That may sound like a weird task after each time you create a Grails / Rails / Spring Roo / … project, since there are going to be many empty directories right from start.

To ease the pain, here is an alias you can add to your “.bashrc” to use before “git add .”:

# add '.gitignore' to all the empty dirs
alias ged='for i in $(find . -type d -regex ``./[^.].*'' -empty); do touch $i"/.gitignore"; done;'

one liner author: justinfrench.com


20
Aug 10

Connect to Wireless Network in Startup

Assuming WPA/WPA2 security is used, first thing to do is to get a hash/hex of the password. Below “myssid” is the wireless network’s SSID, and “mypassword” is the password for this network.

Step 1 Generate a WPA password hash to be used later when setting up network interfaces:

$ wpa_passphrase myssid
# reading passphrase from stdin
mypassword
network={
	ssid="myssid"
	#psk="mypassword"
	psk=2f0568b3492812bd56b946dbaf3fd7dd669b9a4602a09aa6462ff057949b025c
}

Step 2 Configure a wireless network interface using the password hash from Step 1:

$ vi /etc/network/interfaces
   auto wlan0
 
   # configuring a static IP
 
   iface wlan0 inet static
   address 192.168.0.34
   gateway 192.168.0.1
   network  192.168.0.0
   broadcast 192.168.0.255
   netmask 255.255.255.0
 
   #  OR if static IP is not needed ignore above 6 lines and uncomment the one below
   #  iface wlan0 inet dhcp   
 
   # configure WPA/WPA2 security
   wpa-ssid myssid
   wpa-psk 2f0568b3492812bd56b946dbaf3fd7dd669b9a4602a09aa6462ff057949b025c

9
Aug 10

Play Video/Audio on Remote X Server over SSH

export DISPLAY=:0.0
vlc --fullscreen ~/mmedia/video/мультики/снежная-королева.avi

16
Jun 10

IntelliJ IDEA Ubuntu Launcher

IntelliJ IDEA Ubuntu Launcher

IntelliJ IDEA is very easy to install: download and unzip, can’t be simpler.

However creating a launcher for it is not that straightforward, whether it is a Gnome / KDE keyboard shortcut, desktop launcher, docking launcher ( e.g. avant window navigator ) or a simple “Alt+F1″ menu item.

But it is Ubuntu after all: the virtual land of unlimited possibilities.

Here is a simple launcher script that will do the trick:

#!/bin/bash
 
export JAVA_HOME=/usr/lib/jvm/java-6-sun
export JDK_HOME=/usr/lib/jvm/java-6-sun
 
export IDEA_HOME=/opt/idea-IU-95.66
 
export IDEA_VM_OPTIONS="$IDEA_HOME/bin/idea.vmoptions"
export IDEA_PROPERTIES="$IDEA_HOME/bin/idea.properties"
 
cd "$IDEA_HOME/bin"
export LIBXCB_ALLOW_SLOPPY_LOCK=1
 
./idea.sh

A couple of things to note:

1. Point JAVA_HOME and JAVA_JDK to the place where you have JDK installed
2. Point IDEA_HOME where you have IntelliJ IDEA installed
3. Make this script executable e.g. chmod +x idea-launcher.sh [ given that you name it "idea-launcher.sh", of course ]

Now you are free to create any kind of launcher that suites your needs pointing it to this script.


29
Mar 09

Adobe Flex in Ubuntu: Develop, Compile and Run

Flex on UbuntuRecently, browsing InfoQ I stumbled upon a very visual and interesting presentation by Christophe Coenraets “Rich Internet Applications with Flex and AIR“.

This presentation took place during QCon London 2008, where Christophe Coenraets, a Senior Technical Evangelist at Adobe, presented Flex and AIR, two technologies from Adobe used to create, deploy and run Rich Internet Applications.

I have not had any experience with Flex in the past, and, naturally, right after the presentation, I decided to give it a try – to develop, compile, and run an ultra simple Flex application. After some research, I found that there are two choices that are out there for Flex developers:

Adobe® Flex® Builder™ – software is a highly productive Eclipse™ based development tool enabling intelligent coding, interactive step-through debugging, and visual design of the user interface layout, appearance, and behavior of rich Internet applications (RIAs).

OR

Adobe® Flex™ 3 Software Development Kit (SDK) – includes the Flex framework (component class library) and Flex compiler, enabling you to freely develop and deploy Flex applications using an IDE of your choice.

While Adobe® Flex® Builder™ is an appealing option, it is not free. It starts from $300, and goes up to $700 for a professional edition. Whereas Flex SDK is open source and free – which is “a bit” cheaper than $300. The biggest difference between the two is that with just SDK, I will have to use my own IDE / text editor to write Flex applications, which is totally fine by me.

Step 1. Download Flex SDK.

Go to download Flex SDK, and check the box with “I have read the Adobe Flex SDK License, and by downloading the software listed below I agree to the terms of the agreement.”, you should see the “Download the Flex SDK for all Platforms” link to a Flex SDK zip file. Download it.

Unzip it to any directory that you like (in my case it is /opt/flex-sdk)

unzip flex_sdk_3.3.0.4589.zip

Step 2. Create an alias to compile MXML, ActionScript, etc. Flex applications.

Make sure java 6 is installed:

sudo apt-get install sun-java6-jdk

I need to have JAVA_HOME pointed to java 5 (JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun), so I’ll hardcode the path to java 6 into flex compiler alias:

in ~/.bashrc:

# flex SDK home
export FLEX_SDK_HOME=/opt/flex-sdk
alias mxmlc='/usr/lib/jvm/java-6-sun/bin/java -jar "$FLEX_SDK_HOME/lib/mxmlc.jar" +flexlib="$FLEX_SDK_HOME/frameworks" "$@"'

re-login to the terminal (open a new terminal session). Now you can execute:

mxmlc youFlexApp.mxml

to compile an MXML file into an executable “youFlexApp.swf”

Step 3. Write a simple MXML application and compile it with Flex SDK.

Create a simple MXML file “flexTest.mxml”, that would create a button:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
        <mx:Button label="I am a simple flexy button" x="10" y="10" />
</mx:Application>

Compile it:

$ mxmlc flexTest.mxml
Loading configuration file /opt/flex-sdk/frameworks/flex-config.xml
/path/to/flexTest.swf (172884 bytes)

Now you should see a new SWF once the compiler is done:

$ ls -l
total 180
-rw-r--r-- 1 user group    217 2009-03-29 02:38 flexTest.mxml
-rw-r--r-- 1 user group 172884 2009-03-29 02:40 flexTest.swf

Step 4. Run compiled Flex application.

Open it with Firefox (make sure you have Adobe Flash Player plugin installed. If not, install it):

$ firefox flexTest.swf &

Now you should see that flexy button:

a simple button written in MXML and compiled by flex SDK

It is quite simple, really. Good Luck Flexing!


21
Jan 09

That Hardware RAID is FAKE!

Hardware RAIDUbuntu community is straight up about the fact that in the last few years, a number of hardware products have come onto the market claiming to be IDE or SATA RAID controllers. These have shown up in a number of desktop/workstation motherboards. Virtually none of these are true hardware RAID controllers. Instead, they are simply multi-channel disk controllers combined with special BIOS configuration options and software drivers to assist the OS in performing RAID operations. This gives the appearance of a hardware RAID, because the RAID configuration is done using a BIOS setup screen, and the operating system can be booted from the RAID.

If I read it in the news or just while browsing the net, I would not even pay attention, but…

Recently I had to setup a RAID5 on one of the P5 ASUS motherboard on Ubuntu Intrepid with 4 hard drives, 1 TB each . Let me tell you – it seems very “straight up” (like a shot of stoli), but it really is NOT..

Motherboards, like ASUS would claim to have a controller where you can configure a single RAID volume in the BIOS at the “Hardware” level. That is exactly what I tried at first, cause that just makes sense, right?

Well, it appears that this Asus RAID is not in any way “hardware”, therefore Ubuntu installation, sees all 4 drives instead of a single volume, as it should have, in case of a true hardware RAID controller.

So when Intrepid tries to create a Software RAID, out of these 4 drives, it fails, due to the reason that one layer of software RAID is already there – created by Asus.

To solve the problem Asus Raid configuration needed to be wiped out, and the “RAID” option in BIOS for SATA/SCSI should be disabled. Only then Software RAID can be manually created in Ubuntu. Manually, means answer “no” to “Activate Serial ATA RAID devices?” question, and go partition them away manually:

(just an example of a random Ubuntu install screen while configuring RAID1)

configure software raid in ubuntu

Then choose “Configure software RAID”, and create all the multidisk devices (“Create MD device”) from available volumes.

And watch out “that RAID is fake!”. Make sure you do enough research beforehand, to really make sure that the motherboard/controller that has a “Hardware RAID” support in specifications does in reality goes to the metal.

Good luck!


7
Jan 09

Install Adobe Flash Player Firefox Plugin

Flash Player on Ubuntu

Since I upgraded one box to Ubuntu 8.04 (Hardy Heron), and another box to Ubuntu 8.10 (Intrepid Ibex), it was quite irritating for some time to watch youtube videos with no or flaky sound along with skipping videos.

In Firefox, when I went to “Tools -> Add-ons -> Plugins”, or just typed “about:plugins” in the address bar, I saw that I do have “Shockwave Flash 9.0 r124″, however it just dis not want to work smoothly. The same was true for “”Shockwave Flash 9.0 r100″.

So you would think that the right thing to do was to go to the Adobe website: “http://get.adobe.com/flashplayer/“, choose “get the one for Ubuntu 8.04+” option, and download the latest (v10 / v11 / v12 / v13 / v14 / whatever…) flash player, right? Well, not really. After I did that, I saw both “Shockwave Flash 9.0 r124″ and “Shockwave Flash 10.0 r15″, so I disabled 9.0 one, and enabled 10.0 – should be good right? NOPE.

What appeared to be the solution for this mess of flash plugins was to do some “sudo apt-cache search flash…” searches, and figure out what needed to go from both systems.

There were two culprits that overruled the only enabled “Shockwave Flash 10.0 vr15″ plugin: “swfdec-mozilla” and “mozilla-plugin-gnash”. And hence they are going to be removed with all other potential inconsistencies:

sudo apt-get remove -y --purge flashplugin-nonfree gnash gnash-common mozilla-plugin-gnash swfdec-mozilla libflashsupport nspluginwrapper
sudo rm -f /usr/lib/mozilla/plugins/*flash*
sudo rm -f ~/.mozilla/plugins/*flash*
sudo rm -f /usr/lib/firefox/plugins/*flash*
sudo rm -f /usr/lib/firefox-addons/plugins/*flash*
sudo rm -rfd /usr/lib/nspluginwrapper

After this, I had a good feeling and went to http://get.adobe.com/flashplayer/ again, chose “get the one for Ubuntu 8.04+”, saved “install_flash_player_version_linux.deb” locally, and install it with my bare hands:

sudo dpkg -i install_flash_player_10_linux.deb

Restarted Firefox, and let me tell you – Quality of my Ubuntu life has improved significantly since then!
Want to improve the quality of your life significantly? Follow the two steps above :)


6
Jan 09

Find USB flash drive device in Linux

Find USB drive in Linux / Unix

Recently I have written a quick “how to” on restoring, formatting a USB flash drive. The “how to” had a lot of hits from different places since then, mostly from GOOGLE, of course, but some from independent bloggers, like my blogging self.

One of such places was www.newlinuxuser.com. Although the guide “saved them” (welcome :) ) they had a very constructive critique that one thing the guide missed was how to actually find which device to restore / format.

Hence I decided to write a new little 2 step “how to” that will teach you just that.

Step 1. System Log is your friend, listen to what it has to say…

Imagine you close your eyes, and someone puts an apple in your mouth – would you be able to identify what the heck was put into your mouth? For most people the answer would be “yes”. ( If you’d like to experiment, feel free :) . The thing is once you bite on that apple, your brain goes through many lines of code (given that we are written in C), finds that match, and reports:

"The object in your mouth was identified as an Apple - we've had that before.
  I just talked to the stomach, it knows how to digest it."

You would think that your Linux/Unix system is any different? Well, not really.

Right after you insert a USB device into a slot, Linux/Unix will try to read, and identify it. While doing that, it will also assign it to a particular device as “/dev/particular-device”. This device is exactly the information we need, so we can talk to it, and mount it.

Although most people would approach it with running a dmesg, and look at the output, I prefer a more natural OS way to look at things – we’ll look directly in the eye of a System Log!

Let’s use “tail -f”, so we can see real time system log updates:

tail -f /var/log/messages

Now insert your USB drive into a slot and you should see the output similar to:

Dec  5 14:53:19 your-hostname kernel: [81585.308993] usb 4-1: new full speed USB device using uhci_hcd and address 3
Dec  5 14:53:19 your-hostname kernel: [81585.456757] usb 4-1: not running at top speed; connect to a high speed hub
Dec  5 14:53:19 your-hostname kernel: [81585.484884] usb 4-1: configuration #1 chosen from 1 choice
Dec  5 14:53:19 your-hostname kernel: [81585.498817] scsi6 : SCSI emulation for USB Mass Storage devices
Dec  5 14:53:24 your-hostname kernel: [81590.514870] scsi 6:0:0:0: Direct-Access     USB 2.0  USB Flash Drive  0.00 PQ: 0 ANSI: 2
Dec  5 14:53:24 your-hostname kernel: [81590.519874] sd 6:0:0:0: [sdb] 15794175 512-byte hardware sectors (8087 MB)
Dec  5 14:53:24 your-hostname kernel: [81590.522834] sd 6:0:0:0: [sdb] Write Protect is off
Dec  5 14:53:24 your-hostname kernel: [81590.534817] sd 6:0:0:0: [sdb] 15794175 512-byte hardware sectors (8087 MB)
Dec  5 14:53:24 your-hostname kernel: [81590.537814] sd 6:0:0:0: [sdb] Write Protect is off
 
>>>>  Dec  5 14:53:25 your-hostname kernel: [81590.537888]  sdb: sdb1  <---- GOT YOU!
 
Dec  5 14:53:25 your-hostname kernel: [81590.654848] sd 6:0:0:0: [sdb] Attached SCSI removable disk

Note that the USB drive was “connected”, or associated with sdb device

[81590.654848] sd 6:0:0:0: [sdb] 15794175 512-byte hardware sectors (8087 MB)

and more precisely, with sdb1 device

[81590.537888]  sdb: sdb1

And that means we can talk to it! The full name of the guy would be “/dev/sdb1″.

Now let’s greet our friend. Say: “Hi /dev/sdb1″! :)

Step 2. Mount USB drive’s device to the File System.

Just an extra step, in case you need to mount it. If you can’t, and would like to format it, so you can mount it afterwards, read this.

To mount the drive enter this:

sudo mount -t vfat /dev/sdb1 /media/usbdrive/

where “/dev/sdb1″ is the name of the device, we found in the step above. “/media/usbdrive/” is the directory that we are going to mount it to. Make sure this directory exists (otherwise create it “sudo mkdir /media/usbdrive/”). And “-t vfat” is asking your Linux/Unix OS to mount this device as a “vfat” (FAT16, FAT32) device.

Many, if not most, USB devices are VFAT, however if you have an NTFS USB hard drive, for example, you can mount it by entering:

sudo mount -t ntfs-3g /dev/sdb1 /media/usbdrive/ -o force

“sudo” in above couple commands comes from mostly Ubuntu way to “run command as a super user”. If you have any other flavor of Linux/Unix, you may want to just run it as a “root” user.

Eat more apples, and good luck!


17
Nov 08

Configure iwl3945 Driver on Ubuntu

It is quite frustrating when you have a wireless card built in, but you cannot use it – don’t you agree? That seems to be the case for wifi cards that are served by “iwl3945” driver. One of such examples can be “Intel Corporation PRO/Wireless 3945ABG” card.

Before, ( e.g. Feisty and earlier ) “ipw3945” driver was used instead, and worked beautifully with Intel cards. However the active development of this driver has stopped a couple of years ago, which means that security risks that were identified in the last couple of years were not patched. Therefore Ubuntu community switched to a more recent and supported “iwl3945” driver.

However that created a problem with NetworkManager that is used as a default network user interface in (Gnome) Ubuntu. It appears that in order “to be compatible with NetworkManager, a wireless driver must support both hardware and software scanning. Currently, hardware scanning is faster and more reliable and so is recommended for use with NetworkManager“. But unfortunately “iwl3945″ driver does not support hardware scanning very well, however it is a default behaviour that NetworkManager expects.

But usually, and that is what I love Ubuntu for, if there is a problem, there is 99.9999% a solution to this problem. So this how to will help you solve it, and enjoy your Intel Wireless card with Ubuntu, despite of inconsiderate (in this case) NetworkManager.

1. Remove the bad guy

sudo apt-get remove network-manager

2. Disable “iwl3945″ hardware scan

sudo vi /etc/modrobe.d/iwl3945

enter:

	alias wlan0 iwl3945
	options iwl3945 disable_hw_scan=1   # <-- enables software scanning

and save it (:wq).

At this you might want to restart or (optinal) just re-insert the module like this:

sudo modprobe -r iwl3945
sudo modprobe iwl3945

3. Install the good guy

Here you’ll install “the good guy” – his/her name is WICD:

Add wicd’s repository to Ubuntu sources:

sudo vi /etc/apt/sources.list
	 deb http://apt.wicd.net intrepid extras

(if you have Hardy Heron, then add “deb http://apt.wicd.net hardy extras” instead)

Update repositories

   sudo apt-get update

Install wicd “the normal Ubuntu way”:

   sudo apt-get install wicd

4. Run the good guy

   wicd-client

or restart, it should run automatically.

Happy wifying!