December 14, 2010

Installing Hamachi/gHamachi On Ubuntu 10.04

Enable IP Tunneling

1. varsha@varsha-laptop:~$ sudo modprobe tun

2. Add tun to the list of modules.

varsha@varsha-laptop:~$ sudo gedit /etc/modules

3. Add tun to the list on a new line.

4. To verify that we have a valid tunneling node,

i) varsha@varsha-laptop:~$ ls /dev/net/tun
ii) varsha@varsha-laptop:~$ /dev/net/tun


Install Hamachi

1. Download Hamachi from here.

2. Extract the file.

3. cd into the extracted folder.

varsha@varsha-laptop:~$ cd Software/hamachi-0.9.9.9-20-lnx/

4. Install Hamachi.

varsha@varsha-laptop:~/Software/hamachi-0.9.9.9-20-lnx$ sudo make install


Set User Permissions

1. Create group hamachi.

varsha@varsha-laptop:~$ sudo groupadd hamachi

2. Add your user and root to the group hamachi. (My user is varsha.)
i) varsha@varsha-laptop:~$ sudo gpasswd -a varsha hamachi
ii) varsha@varsha-laptop:~$ sudo gpasswd -a root hamachi

3. Change the socket permissions.

varsha@varsha-laptop:~$ sudo chmod 760 /var/run/tuncfg.sock

4. Change the group of the file.

varsha@varsha-laptop:~$ sudo chgrp hamachi /var/run/tuncfg.sock


Start Hamachi

varsha@varsha-laptop:~$ sudo tuncfg

1. Set the initial configuration.

varsha@varsha-laptop:~$ hamachi-init -c /etc/hamachi

2. Start Hamachi.

varsha@varsha-laptop:~$ sudo hamachi -c /etc/hamachi start

3. Set your nick.

varsha@varsha-laptop:~$ hamachi -c /etc/hamachi set-nick nickname.

Replace nickname with the desired nick.

4. Log into Hamachi.

varsha@varsha-laptop:~$ sudo hamachi -c /etc/hamachi login


Use Hamachi

1. To create your own network,

varsha@varsha-laptop:~$ sudo hamachi -c /etc/hamachi create network password


Replace network and password with the desired network name and password.

2. To join an existing network,

varsha@varsha-laptop:~$ sudo hamachi -c /etc/hamachi join network password


3. Go online on the network, you just created.

varsha@varsha-laptop:~$ sudo hamachi -c /etc/hamachi go-online network



Install gHamachi

1. Download the file from here.

2. Extract the file.

3. Run the executable file ghamachi.

varsha@varsha-laptop:~$ ./ghamachi


[Source: http://www.supware.net/other-fun-stuff/hamachiubuntuhowto/]




November 7, 2010

A Trick In Nokia

Most of you like downloading applications for your mobile phone, but in my case I can't do that due to some subscription problem. So, what I generally do is download the applications on my laptop and then transfer to my phone. But I am extremely particular about the location of the application- I don't want it to be just anywhere, but in the Applications menu, which is not really possible, whether you use Bluetooth or data cable.

This is a trick I tried out in my Nokia 2700 mobile phone. I am not sure for how many of you this will work. I presume you use Linux (my distro Ubuntu). Create a folder called Applications beforehand inside Gallery. Via Bluetooth, browse and open the Gallery on your phone, and copy the application files into the folder you created. On your phone, open the folder- it will be empty (even though you copied the application files into it). Now go to Applications menu from the main menu, and hopefully you'll find the application there.

It worked for me.

Note: This works via Bluetooth, and not data cable.




September 25, 2010

Installing Wordpress 3.01 In Ubuntu 10.04

Wordpress is an Open CMS and often used for blogging.


Installation

1. Make sure you have Apache, MySQL and phpMyAdmin installed.

2. Download the source from the Wordpress website.

3. Extract the source mv it to /var/www/.

4. Next, we need to create a database for Wordpress. This can be done using phpMyAdmin or MySQL.

(a) Using phpMyAdmin,

i) Log in to phpMyAdmin, and enter a database name of your choice, for example wordpress. Click Create.

ii) Go to Privileges, and see if there's a user for wordpress. If not, then create one. Click on Add a new user, and enter a user name and a password for the user. Make sure you have Use text field: selected in the drop down menu.

iii) Click Go.

iv) GO to Privileges again and click the Edit icon in the last column Action of User overview for wordpress.

v) Under Database-specific privileges, select wordpress from the Add privileges to the following database drop down menu. The page refreshes. Click Check All to select all privileges, and click Go.


(b) Using MySQL,

i) varsha@varsha-laptop:/var/www$ mysql -u root -p
Enter password:


ii) mysql> CREATE DATABASE wordpress;

iii) Assuming you are creating a user wp_user for the database wordpress (you may use a different username),

mysql> CREATE USER wp_user;


iv) Choose a password of your choice.

mysql> SET PASSWORD FOR wp_user = PASSWORD("password");


v) mysql> GRANT ALL PRIVILEGES ON wordpress.* TO "wp_user"@”localhost” IDENTIFIED BY "password";

vi) mysql> FLUSH PRIVILEGES;

vii) mysql> EXIT


Configuration


1. Go to the wordpress directory.

varsha@varsha-laptop:~$ cd /var/www/wordpress

2.We need a configuration file for Wordpress.

varsha@varsha-laptop:/var/www$ sudo cp wp-config-sample.php wp-config.php

varsha@varsha-laptop:/var/www$ sudo gedit wp-config.php

Go to the 19th line and make changes accordingly.

// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'wordpress');

/** MySQL database username */
define('DB_USER', 'wp_user');

/** MySQL database password */
define('DB_PASSWORD', 'password');

/** MySQL hostname */
define('DB_HOST', 'localhost');

Save and exit.

3. Open your browser and in the address bar type: http://127.0.0.1/wordpress/. You'll get a Wordpress Welcome page. Enter a Site Title, Username, Password and Your E-mail. Check Allow my site to appear in search engines like Google and Technorati, if you opt for it. Click Install Wordpress.


Installation complete!



September 24, 2010

Installing C/C++ Plugin In Eclipse

Eclipse has long been used for developing Java applications. When it comes to C/C++, developers familiar with Eclipse would like to use the same, rather than shifting to another IDE.

After Googling for quite long, I came across many links, but most of them were tutorials for downloading Eclipse CDT (C/C++ Development Tooling) IDE. I prefer a plugin for the existing IDE, instead of a separate IDE, even though Eclipse.


Installing Eclipse CDT IDE

1. Download from here.

2. Extract the archive, configure, compile and install.

Installing C/C++ Plugin In Eclipse IDE

1. From Help-> Install New Software..., go to the Install window.

2. Enter the location http://download.eclipse.org/tools/cdt/releases/galileo for Eclipse Galileo (3.5) or http://download.eclipse.org/tools/cdt/releases/helios for Eclipse Helios (3.6). Click Add.

3. Select the items you need to install. I selected the following.

(a) Under CDT Main Features

i) Eclipse C/C++ Development Tools

(b) Under CDT Optional Features

i) CDT GNU Toolchain Build Support
ii) CDT GNU Toolchain Debug Support
iii) CDT Utilities
iv) Eclipse C/C++ Development Platform

Note: If you select all, some of the items may not be installed.

Then click Next.

4. You get a review window. Click Next.

5. Accept the terms and conditions and click Finish.

6. After completion of the plugin, Eclipse asks you for a restart. Click Yes.


Installation successful!

[Source:

1. http://wiki.eclipse.org/CDT/User/FAQ
2. http://max.berger.name/howto/cdt/ar01s04.jsp
]



September 23, 2010

Installing Drupal In Ubuntu 10.04

Drupal is a an Open Source Content Management System. Installation of Drupal on Ubuntu 10.04 is relatively easy. Just follow the simple steps below:

1. Open a terminal and type:

varsha@varsha-laptop:~$ sudo apt-get install drupal6

2. You'll be prompted to select the database. With your arrow keys select mysql and press enter.

3. Enter your MySQL password when you are asked to. This creates a database schema called drupal6 in your MySQL RDBMS.

This is also supposed to auto-create the necessary files in the /var/www/ directory. But it didn't in my case, so I had to go for manual creation of files. Continue with the following steps only if you do not have a drupal directory in /var/www/.

4. Download the drupal6 source from http://ftp.drupal.org/files/projects/drupal-6.15.tar.gz. Extract and do the following.

5. Create the necessary directory in /var/www/.

varsha@varsha-laptop:~$ sudo mkdir /var/www/drupal

6. Copy the contents of the extracted directory into /var/www/drupal/.

varsha@varsha-laptop:~$ sudo mv drupal-6.15/* drupal-6.15/.htaccess /var/www/drupal

7. Create a directory files in drupal/sites/.

varsha@varsha-laptop:~$ sudo mkdir /var/www/drupal/sites/default/files

8. Change the owner of the directory.

varsha@varsha-laptop:~$ sudo chown www-data:www-data /var/www/drupal/sites/default/files

9. Create the initial configuration files.

varsha@varsha-laptop:~$ sudo cp /var/www/drupal/sites/default/default.settings.php /var/www/drupal/sites/default/settings.php

10. Change the owner of the file settings.php.

varsha@varsha-laptop:~$ sudo chown www-data:www-data /var/www/drupal/sites/default/settings.php

11. Create a database drupal6 using phpMyAdmin.

varsha@varsha-laptop:~$ mysqladmin -u root -p create drupal6

12. Log in to MySQL if you already have lamp-server installed on your system.

varsha@varsha-laptop:~$ mysql -u root -p

13. Grant permissions to the root user (or the username you log into MySQL with) on all tables in drupal6 schema.

mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES ON drupal6.* TO 'username'@'localhost' IDENTIFIED BY 'password';

Here, 'username' is either root or any other username you use to log into MySQL and 'password' is the password of the username.

14. Open your browser and type http://localhost/drupal/. You'll get the following page if you haven't created a database for Drupal.




Enter the details and click on Save and continue.

15. Next you'll get a screen as follows.



Enter your email address under Site information. Under Administrator account, enter a username, email address and password. I used my phpMyAdmin username and password and my email address. Click Save and continue.

16. Then you get a page saying "Drupal installation complete". Go to your new site.




Installation complete!



Using GIT Behind Proxy

GIT uses GIT protocol. So if you need to clone any source, you need to do the following:

1. varsha@varsha-laptop:~$ git clone git://git.gnome.org/path/of/source

2. If the above works fine for you, then you don't have to do anything else. Otherwise, if you get the following error, then proceed to Step 3.

git.gnome.org[0: 209.132.180.173]: errno=Connection timed out
fatal: unable to connect a socket (Connection timed out)

3. Check if you have set up your system proxy.

varsha@varsha-laptop:~$ echo $http_proxy
http://172.16.1.13:3128/


4. If not, set the proxy.

export http_proxy="<address:port>"

5. Try cloning from GIT again, but this time use http:// instead of git://.

varsha@varsha-laptop:~$ git clone http://git.gnome.org/path/of/source



September 6, 2010

Installing Apache Mahout In Ubuntu 10.04

Apache Mahout is a project that helps in making intelligent applications.

Pre-Requisites

1. JDK 1.6 or higher
2. Ant 1.7 or higher
3. Maven 2.0.9 or 2.0.10 (needed if you want to build Mahout source)

Installation

1. Download the sample code.

2. Unzip the downloaded file.

varsha@varsha-laptop:~$ unzip j-mahout.zip

3. Go into the extracted directory.

varsha@varsha-laptop:~$ cd apache-mahout-examples

4. Install.

varsha@varsha-laptop:~/
apache-mahout-examples$ ant install


Possible errors you may encounter

1. Error: JAVA_HOME is not defined correctly. We cannot execute java Bootstrap FAILED ubuntu

Solution:

varsha@varsha-laptop:~$ export JAVA_HOME=/usr/lib/jvm/java-6-sun-1.6.0.20

Look into
/usr/lib/jvm/ to know what JDK is installed on your system.

2. BUILD FAILED
/home/varsha/apache-mahout-examples/build.xml:92: The following error occurred while executing this line:
/home/varsha/apache-mahout-examples/build.xml:85: java.net.ConnectException: Connection timed out


Solution:

i) Go to Line 81, and comment out:


<target name="get-enwiki" depends="check-files" unless="enwiki.exists">

<echo>Downloading Wikipedia Data - (~2.5GB)</echo>

<get src="http://people.apache.org/~gsingers/wikipedia/enwiki-20070527-pages-articles.xml.bz2"

dest="${wiki.dir}/enwiki-20070527-pages-articles.xml.bz2"/>

</target>



ii) About five lines below that, comment out:


<antcall target="get-enwiki"/>

This is 2.5 GB of compressed wiki pages.

iii) Download manually enwiki-20070527-pages-articles.xml.bz2 and save in apache-mahout-examples/wikipedia/.

iv) Go down to 141st line and comment the following:


<echo>Downloading Clustering data (9.2M)</echo>

<get src="http://people.apache.org/~gsingers/wikipedia/n2.tar.gz"

dest="${wiki.dir}/n2.tar.gz"/>


v) Download manually
n2.tar.gz and save in apache-mahout-examples/wikipedia/.



September 5, 2010

Tricks For Smooth Scrolls And Clicks In Firefox

You can find almost anything in the Firefox configurations page.

For smooth scroll

1. Type about:config in the address bar in a new tab.

2. Click on the warning I'll be careful, I promise!

3. Type smooth in the filter bar.

4. Double click general.smoothScroll. This changes it value from false to true.

For smooth clicks

1. Type dom.ipc.plugins.enabled in the filter bar.

2. Set the value to true by double clicking on the name.

3. Restart the browser for both the effects to take place.



August 29, 2010

Installing TweetDeck In Ubuntu 10.04

Follow the simple steps below in order to install TweetDeck on your Ubuntu system.

Install Adobe AIR

You can install Adobe AIR either from Synaptic Package Manager or Ubuntu Software Centre or from the Adobe site. In case you decide to install from the site, download and double click the downloaded file, or select Open with GDebi Package Installer.

Install TweetDeck

Go to link, and download file, or directly open with Adobe Air by selecting Open with Adobe AIR Application Installer.

In my case, the usual link did not work. Clicking on Download now, it's free showed me Installing TweetDeck button for more than hour.


Happy tweeting!



Meddling Around With Namoroka

After having installed Namoroka on my Ubuntu system, I found the following discrepancies.

1. No Facebook Chat

i) Open a new tab in Namoroka. Type about:config in the address bar.

ii) Search for general.useragent.extra.firefox.

iii) Under value, double-click Namoroka 3.6.2pre and replace it with Firefox.

iv) Restart your browser.


2. Echofon doesn't work. You get the error "Echofon does not support this platform or custom build Firefox. (Can't get OAuth signer.)"

Installing an older version of Echofon solved this problem, thanks to Manohar Bhattarai of LUG@IITD mailing list. Download this version (1.9.6.4) of Echofon from https://addons.mozilla.org/en-US/firefox/addon/5081/eula/88620?src=version-history.


[Source:

1.
http://support.mozilla.com/tiki-view_forum_thread.php?locale=lt&comments_parentId=659480&forumId=1

2. http://groups.google.com/group/iitdlug/browse_thread/thread/4c7c6012d7f846f

]



August 28, 2010

Firefox And Namoroka

In an attempt to install Firefox 4, I accidentally bumped into Namoroka.

Seems like the PUBKEY EF4186FE247510BE isn't available at the moment. I tried exporting the key, as given on Rectifying apt-get GPG Error, but couldn't succeed. Adding the repository ppa:ubuntu-mozilla-daily/ppa did not work either.

Then on searching in Synaptic Package Manager, I found that firefox-4 was there (much to my surprise, as adding the repository failed). I installed it, and found that Namoroka Firefox pre-release has been installed on my Ubuntu 10.04 system. It is Firefox after all, but not the usual one we prefer.


Obviously there are a few changes and incapabilities, which I'll discuss in the next post.



August 27, 2010

Solving "Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName" in Ubuntu 10.04

All of a sudden, I wasn't able to open localhost on my browser, and I realized I wasn't able to restart Apache2.

varsha@varsha-laptop:~$ sudo /etc/init.d/apache2 restart
* Restarting web server apache2
apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName


I found a simple solution, as given on http://mohamedaslam.com/how-to-fix-apache-could-not-reliably-determine-the-servers-fully-qualified-domain-name-using-127011-for-servername-error-on-ubuntu/.

Helped a lot!



Setting Up Proxy For Subclipse In Ubuntu

After installing the Subversion Eclipse Plugin in Eclipse, I wasn't able to add an SVN repository. I was getting the error RA layer request failed in eclipse. I realized that it was due to incorrect proxy settings that I wasn't able to connect to the SVN server. Configuring proxy in this case may not be as easy as entering the address and port number in Eclipse preferences.

To set up the proxy for the SVN server, do the following:

1. varsha@varsha-laptop:~$ cd .subversion/

2. varsha@varsha-laptop:~/.subversion$ ls

3. varsha@varsha-laptop:~/.subversion$ gedit servers

4. In the servers file, find the lines with http-proxy-host and http-proxy-port under [global] section.

5. Uncomment those lines and enter the host address and the port number respectively for http-proxy-host and http-proxy-port.

6. Save and close the editor.

7. In the SVN Repository view in Eclipse, try adding a new repository location.

Hope it works.


Note: Make sure you don't leave a space before the statements after uncommenting the two lines as said above, else you are likely to get the error
Cannot map the project with svn provider.



August 21, 2010

Use Of "sudo cd" Command

There are certain privileged directories on the Linux system, that a normal user can't access. You need to know the root password or at least be a sudoer to access those directories. Some people try sudo cd to cd into such directories, but end up with an error. I am describing a few here along with the explanation.

1. sudo cd does not work.

varsha@varsha-laptop:~$ sudo cd /etc

[sudo] password for varsha:
sudo: cd: command not found


Explanation: cd is a shell command, and not a program. So, when you try sudo cd, there is no program that can be launched, and so you get the error sudo: cd: command not found.

Also, there is a list of commands that can be run by certain users and not ALL commands can be run. This is maintained through a sudoers file. See:

varsha@varsha-laptop:~$ man sudoers

2. Becoming root first, and then the cd command works.

varsha@varsha-laptop:~$ su
Password:
root@varsha-laptop:/home/varsha# cd /directory-path
root@varsha-laptop:/directory-path#


Explanation: Anyone can use sudo to enter a directory and manipulate files, so this calls for the use of su instead of sudo.

Thanks to Sharad Birmiwal for some of the information. Please refer to http://groups.google.com/group/iitdlug/browse_thread/thread/c1523585d9fc7987 for the discussion.



August 5, 2010

Solving Error "E: Sub-process /usr/bin/dpkg returned an error code (2)" In Ubuntu 10.04

I noticed that suddenly my Synaptic and apt-get weren't installing any package on my new Ubuntu 10.04. On looking at the details, I found the following error being flashed:

dpkg: unrecoverable fatal error, aborting:
statoverride statoverride unknown group gnokii
E: Sub-process /usr/bin/dpkg returned an error code (2)


I Googled and found the following two links:

1. http://ubuntuforums.org/showthread.php?t=508679

2. http://ubuntuforums.org/archive/index.php/t-329560.html

From the two links above, I knew I had to see or even edit my /var/lib/dpkg/statoverride file.

It contained:

root mlocate 2755 /usr/bin/mlocate
hplip root 755 /var/run/hplip
root gnokii 4750 /usr/sbin/mgnokiidev


I deleted the last line "root gnokii 4750 /usr/sbin/mgnokiidev". But it gave a similar error:

dpkg: unrecoverable fatal error, aborting:
statoverride file contains empty line
E: Sub-process /usr/bin/dpkg returned an error code (2)


This was shocking as the file isn't empty.

Then, I realized that my cursor was on an empty line. Doing a backspace and bringing it to the last non-empty line solved the problem, irrespective of the line "root gnokii 4750 /usr/sbin/mgnokiidev" being present in the file.

It wasn't a serious problem anyways.



July 5, 2010

Resolving "Failed to create tables in database" Error In digiKam

To resolve the error "Failed to create tables in database" in digiKam, follow the steps given below:

1. Kill the process, if it is running.

varsha@varsha-laptop:~$ ps aux | grep digikam
varsha@varsha-laptop:~$ kill pid


Note: The pid is the process ID of the digiKam process that will be shown in the output of the first command. (Eg. 2752)

2. Delete your digiKam config file, ~/.kde/share/config/digikamrc.

3. Delete the files (digikam4.db) created by digiKam in the folder you had initially specified as the library folder. For example, I had selected the folder Pictures in my Windows 7 drive. (Seems like the error was because the library folder was on an NTFS partition.)

4. Launch your digiKam.

5. Take all the default options specified, clicking Next, and then finally Finish.

6. Go to Settings-> Configure digiKam..., click Add Collection and select the folders you want, in which you have your images stored. Click OK. All the folders and images will be added to your Album.

[Source:

1. http://ubuntuforums.org/archive/index.php/t-913339.html

2. http://bbs.archlinux.org/viewtopic.php?id=96413
]





June 18, 2010

Splitting Videos In Ubuntu

Splitting videos has been a concern over a long time, until recently I found out a simple technique that uses an equally simple command. For this all you have to do is install ffmpeg, either from Synaptic Package Manager or command-line apt-get or aptitude (Ubuntu), or yum, zypper, etc. in case of other distros.

First cd to the directory where you have your video. Then,

varsha@varsha-laptop:~$ ffmpeg -i video_name -ss 00:04:00 -t 00:05:16 "video-part1.avi"

Here,

-i
specifies the name of the input file

-ss stands for position in hr:min:sec format where you want the splitting to begin

-t is the duration of the new file

My specification here is to split the video after 4 minutes elapsing from the start time of the original video and having a duration of 5 minutes and 16 seconds.

You can split into multiple parts at the same time.

varsha@varsha-laptop:~$ ffmpeg -i video_name -ss 00:00:10 -t 00:00:30 part1.avi -ss 00:00:35 -t 00:00:30 part2.avi

This creates part1.avi of 30 seconds duration starting from the 10 second of the original video and part2.avi of 30 seconds duration starting from the 35th second of the original video.

[Note: 1. The output file must have a proper recognized format.

2. Check out the manual for more information and details.

varsha@varsha-laptop:~$ man ffmpeg
]



June 16, 2010

Installing GWT On Ubuntu 10.04

GWT (Google Web Toolkit), is a development toolkit for building web applications.

You can have a look at the Getting Started page for a basic knowledge. Installation too is easy enough.


Pre-requisites for Installation

1. OpenJDK Development Kit (JDK) version 1.5 or later

2. Apache Ant


Installation

1. Install Eclipse or Netbeans. I am using Eclipse.

2. Install the Eclipse-plugin. Refer http://code.google.com/eclipse/docs/download.html.

3. Install the GWT SDK. Refer http://code.google.com/webtoolkit/gettingstarted.html#installing.


Getting Started With Applications

Refer to the following pages.

1. Getting Started With GWT SDK

2. GWT In Action


[Note: Install JDK, Apache Ant and Eclipse (or NetBeans) using apt-get or Synaptic Package Manager (or from Ubuntu Software Center for Ubuntu 9.10 and later).]



March 19, 2010

Shell Script For Converting Between Different Audio Formats

All the media players do not support all audio formats. For this, we may need to convert from one format to another. The following step describe how we can do this, and is applicable to almost all formats.

Using Mencoder

Check out my post at Conversion From One Audio Format To Another Using Mencoder. If this doesn't help, you can follow the steps given below.

Using Shell Script

1. Open the terminal, and type,


varsha@varsha-laptop:~$ cd ~/.gnome2/nautilus-scripts

2. Open a new script,

varsha@varsha-laptop:~/.gnome2/nautilus-scripts$ gedit convert\ any\ to\ mp3.sh

3. Type the following code in the file.

mplayer -ao pcm "$1" -ao pcm:file=temp.wav
OUTNAME="${1%%.wma}.mp3"
lame -b 128 temp.wav "$OUTNAME"
rm temp.wav


4. Comment out rm temp.wav if you do not want to remove the temporary file temp.wav, by prepending the line with a #. So,

#rm temp.wav

5. Save the file and close the editor.

6. To convert any file to mp3, right-click the file and select Scripts-> convert any to mp3.sh.



March 12, 2010

Installing KDE Packages In Ubuntu 9.10

To install KDE packages in Ubuntu 9.10 (or in any distro for that matter), you can refer to the following links:

1. http://linuxappfinder.com/

2. ftp://ftp.kde.org/pub/kde/stable/




February 24, 2010

Syncing Ubuntu System Time With Network Time

Try one of the following to sync your system time with the network time.

1. Check whether your system date and time are correct. If not, set the correct date and time.

2. You can also try System-> Administration-> Time and Date.

i) Unlock.

ii) Select Keep synchronized with Internet servers.

iii) If you are asked to install NTP support, click Install NTP support.

iv) Click Select Servers, and check required servers, or add a new one by typing URL of the server in the textbox clicking the Add button.

3. Please refer to the post Removing SSL Certificate Error In Ubuntu.



Removing SSL Certificate Expiry Error In Ubuntu

SSL certificate error for any site shows up when your system time is not in sync with the network time. If you view the details, you'll find that the date shown is in the past. To sync your system time, you can use ntpdate.

1. If it is not already installed, install it first.

varsha@varsha-laptop:~$ sudo apt-get install ntpdate

2. If it is already installed, try syncing the time.

varsha@varsha-laptop:~$ sudo /etc/network/if-up.d/ntpdate

Or,

varsha@varsha-laptop:~$ sudo ntpdate ntp.ubuntu.com

3. Try editing the ntpdate file.

varsha@varsha-laptop:~$ sudo gedit /etc/default/ntpdate

The file looks like:

# servers to check. (Separate multiple servers with spaces.)
NTPSERVERS=”0.debian.pool.ntp.org 1.debian.pool.ntp.org 2.debian.pool.ntp.org 3.debian.pool.ntp.org”
#
# additional options for ntpdate
#NTPOPTIONS=”-v”
NTPOPTIONS=”-u”
NTPSERVERS=”ntp.ubuntu.com”

If you have your own NTP server, list it under NTPSERVERS.

Save and exit the editor.

4. Now, use cronjob to run ntpdate every hour.

varsha@varsha-laptop:~$ crontab -e

In the file, type the following.

#Setup NTPDATE
@hourly /etc/network/if-up.d/ntpdate

Save and exit. See the options at the bottom of the terminal for help.

5. Try updating again.

varsha@varsha-laptop:~$ sudo /etc/network/if-up.d/ntpdate

Try opening any site. You will at least get the option of adding an exception.


[Source:

1. http://www.askdavetaylor.com/invalid_or_expired_security_certificate.html

2. http://www.ubuntugeek.com/keeping-your-system-clock-current-automatically-via-network-time-protocol-ntp.html

3. http://www.cyberciti.biz/faq/set-date-time-network-time-protocol-ntp/

4. http://www.howtogeek.com/howto/ubuntu/sync-your-system-clock-with-internet-time-servers-in-ubuntu/ (for Ubuntu 8.10)
]



February 23, 2010

Recovering File System In Linux

When your Linux doesn't give you a GUI, I know how it feels. It happened to me, and I felt like screaming my head off, which of course was of no use. Later I found that the file system had somehow got errors on it. I tried a number of things, some of which were helpful.

Listing it all down,

1. I booted into recovery mode, even when the normal mode failed, it took me to the shell prompt, where I was root by default.

2. I tried http://forums.techarena.in/operating-systems/1241547.htm. This didn't do much good.

3. I tried /etc/init.d/gdm restart and /etc/init.d/gdm start. This gave me a message box with the following error message.

Ubuntu is running in low-graphics mode.
The following error was encountered. You may need to update your configuration to solve this. (EE) Failed to load module "i810" (Module does not exist, 0)


But the screen got hanged and again made me turn off my laptop using the power button. So, it didn't help basically, the reason being there was no problem with the GDM, there were errors in the file system.

4. fsck did the magic. I tried a few times, then used Windows to post my query to different mailing lists. A. Mani and Prosun Prodhan of iitd mailing list helped me out.

5. On typing fsck, I somehow had a feeling that it was working to some extent.

#fsck
mountall: fsck/ [856] terminated with status 4
mountall: Filesystem has errors:/
init: mountall main process (852) terminated with status with status 3
Mount of filesystem failed.
Fix<y>? yes


This gave me the following:

/dev/sda6: ***********FILESYSTEM WAS MODIFIED****************
/dev/sda6: ***********REBOOT LINUX***********
/dev/sda6: 228389/1212416 files (0.2% non-contiguous), 110712/4849614 blocks

Then I rebooted.
#reboot

I tried this a number of times, until I booted with an Ubuntu live CD and did the same, and it finally gave me the default GUI mode.

Thanks to all who helped.

I don't know why this happened, but probably because I had not shut it down properly. I had to turn off my laptop with the power button, because it got hanged on inserting a pendrive infected with virus from the lab.


Note: Repeated use of fsck must be avoided. The first thing to focus on is your filesystem. That shouldn't be harmed.



February 20, 2010

Twitter On Pidgin

This post of mine is similar to the previous one. You can use Twitter on Pidgin. For this, do the following:

1. Install pidgin-mbpurple plugin, from Synaptic Package Manager or aptitude (for Ubuntu/ Debian). You can also download it from here. Another option is to check the plugin twitgin from Tools-> Plugins.

2. Restart Pidgin.

3. Add a new account, choosing the protocol TwitterIM. Enter your Twitter username and password under 'Basic', and set your proxy under 'Proxy' tab.

4. Check this account in Accounts window.

Happy tweeting. :)



Facebook Chat On Pidgin

Wondering why there is no IM client for Facebook, I just Googled a bit to find that there is a plugin for Pidgin that allows users to configure their Facebook account. What I did was:

1. Install the plugin pidgin-facebookchat. You can use your Synaptic Package Manager or aptitude (in case of Ubuntu/ Debian), or, if that is an older version, then download the latest file from here.

2. Double-click the .deb file and click Install Package. You'll probably have to configure, compile and install the package if you download the .tar.gz version.

3. Restart Pidgin.

4. Select Manage Accounts from Accounts, and click on Add....

5. Select protocol Facebook, enter your username and password under tab 'Basic'. Under 'Advanced', check your preferences, and under 'Proxy', set your proxy (if applicable).

6. Then check your Facebook account in the Accounts window.

That's it. :)



February 12, 2010

Converting .rpm Package To .deb

Alien is a program that converts between different file formats. If you want to use a package from another distribution, you can use alien to convert it to your preferred package format and install it.

Alien can be used to convert a .rpm package to .deb. If you have downloaded a .rpm package instead of a .deb, you need not refetch the correct package. You can do the following:

Install Alien

1. Download from here.

2. You can also install via command line.

varsha@varsha-laptop:~$ sudo apt-get install alien


Convert .rpm Package To .deb

1. Convert the package to .deb using the alien command.

varsha@varsha-laptop:~$ alien package_name.rpm

This takes the latest version of the package.

If you want the current version,

varsha@varsha-laptop:~$ alien -k package_name.rpm

2. To install the package, use dpkg command.

varsha@varsha-laptop:~$ dpkg -i package_name.deb

You can also use the alien command to directly install the package after converting.

varsha@varsha-laptop:~$ alien -i package_name.rpm

Note: See the manual for details on how to use the command.

varsha@varsha-laptop:~$ man alien



February 7, 2010

Installing qGTalk In Ubuntu 9.10

A few days back I came to know about qGTalk. So I decided to give it a try.

Installation

1. Download the package from here.

2. Then, check whether the dependencies, i.e., libglib2.0-dev, libqt4-dev, g++, libgloox and Qt 4.3 are met.

If you have problems resolving the dependencies, try installing from Synaptic Package Manager or apt-get or try downloading the package. In my case, libglib2.0-dev, libqt4-dev and libgloox weren't installed, and I also had problem in installing them using the package managers. So, I downloaded them.

i) Open a terminal and type:

varsha@varsha-laptop:~$ wget http://launchpadlibrarian.net/24833148/libqt4-dev_4.5.0-0ubuntu4_i386.deb

libglib2.0-dev can be installed using Synaptic Package Manager, but if you wish to download,

varsha@varsha-laptop:~$ wget http://launchpadlibrarian.net/36376694/libglib2.0-dev_2.22.3-0ubuntu1_i386.deb

varsha@varsha-laptop:~$ wget http://camaya.net/download/gloox-1.0.tar.bz2

(With the help of Irfan from nitdgplug mailing list.)

ii) Double-click and install the .deb files. For installing gloox-1.0, extract, configure, compile and install. Read the INSTALL file in the extracted folder.

3. Then, follow the steps given on the same page.

varsha@varsha-laptop:~$ tar zxf qGTalk_en-0.1.9.tar.gz
varsha@varsha-laptop:~$ cd qGTalk_en-0.1.9/
varsha@varsha-laptop:~$ qmake-qt4 qGTalk.pro
varsha@varsha-laptop:~$ make
varsha@varsha-laptop:~$ sudo make install

4. Launch it from Applications-> Internet-> qGTalk.

Removal

varsha@varsha-laptop:~$ /qGTalk_en-0.1.9/qGTalk/
varsha@varsha-laptop:~/qGTalk_en-0.1.9/qGTalk/$ sudo make uninstall

This might show you an error, but removes qGTalk from your system.