GRUB 2 recovery

We often come across a condition in which the boot loader gets corrupt. Here are a few steps that will help you recover your GRUB 2 boot loader.
Boot from a live CD or DVD, which supports GRUB 2 (Ubuntu 9.10 CD or above. A DVD will take more time than a CD, so I suggest you boot from a CD).
Open the terminal and run fdisk -l to check the partition from which you want to recover GRUB 2.
Here I assume that you want to recover it from /dev/sda1.
Then run the following commands:
 
sudo mkdir /media/sda1
sudo mount /dev/sda1 /media/sda1
sudo mount --bind /dev /media/sda1/dev
sudo mount --bind /proc /media/sda1/proc
Now chroot into that partition by running the command given below:

sudo chroot /media/sda1


Then re-install GRUB, as follows:

grub-install /dev/sda

The output should be like what’s shown below:

Installation finished. No error reported.

If you get an error, then try the following command:

grub-install --recheck /dev/sda

After a successful installation, exit from chroot and unmount the file systems that were mounted to recover GRUB. Now reboot.

exit
sudo umount /media/sda1/proc
sudo umount /media/sda1/dev
sudo umount /media/sda1
sudo reboot


You’ve successfully completed recovering your GRUB boot loader.

Information courtesy: EFYTimes News

How to force install .deb package

In certain contexts debian packages are reluctant to install using gdebi or software center due to dependencies problem. In that case, you can install .deb file using following command,

dpkg --force-all -i PackageName

e.g. dpkg --force-all -i google-chrome-stable_current_i386.deb

How to fix E: Could not get lock /var/lib/apt/lists/lock problem


You got following message when you try to run apt-get update command in Ubuntu?

E: Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable)
E: Unable to lock directory /var/lib/apt/lists/
E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

 Solution

1. Search for processes

ps -A | grep apt-get

2. See if there is any process running as apt-get then kill that process

sudo kill -9 

If the error persists, apply following commands in a termina,

sudo su
sudo rm /var/lib/apt/lists/lock
apt-get update


How to Install Broadcom Wireless Driver (BCM4313) in Ubuntu / Xubuntu 12.04

I tried following method to install Broadcom wireless Driver with Dell Vostro 3500  in Ubuntu/Xubuntu 12.04 (64 bit) Linux.

First of all check your wireless chipset model number,

lspci | grep Network

Install following prerequisites,

sudo apt-get install linux-headers-generic build-essential dkms

Download the package from here,

Open following file,

gedit /etc/modprobe.d/blacklist.conf

Add following lines,

blacklist b43
blacklist b43legacy
blacklist bcma
blacklist ndiswrapper


Comment the following line,

# blacklist bcm43xx

Restart laptop and check wireless working or not.

Mobile media converter

Mobile Media Converter is a helpful tool for mobile users to cross platform transfer of media files. It can handle various formats like MP3, Windows Media Audio (wma), Ogg Vorbis Audio (ogg), Wave Audio (wav), MPEG video, AVI, Windows Media Video (wmv), Flash Video (flv), QuickTime Video (mov) and commonly used mobile devices/phones formats like AMR and 3GA audio (amr) and 3GP video.


Here is the link to mobile Media Converter

Install HP LaserJet P1108 printer in Ubuntu 12.04

Visit the following page to install HP Laserjet P1108 in Ubuntu 16.04 / Debian 8.
http://linuxhalwa.blogspot.in/2017/06/install-hp-laserjet-p1108-printer-in-ubuntu.16.04.html

You can find that HP LaserJet P1108 do not work simply adding printer with Ubuntu 12.04. You have to execute following commands to configure the printer


sudo apt-get install python-qt4
sudo apt-get install hplip-cups
sudo hp-setup


User settings,

sudo adduser vimal lp
sudo adduser vimal lpadmin

Replace vimal with your user name. 

Install Drupal on Ubuntu 12.04

Drupal is an Open Source content management system. Drupal is very powerful, flexible and popular among web developers. Whitehouse website build on Drupal.


Now Drupal is now available with Ubuntu 12.04 software repository and very easy to install. Please follow the instructions to install Druapl on your Ubuntu 12.04 server or desktop.

Install LAMP server
LAMP package contain MySQL, Apache and PHP.

apt-get update
apt-get upgrade
apt-get install lamp-server^

Enter MySQL root password during installation. 

Enable rewrite function in Apache,

sudo a2enmod rewrite
sudo service apache2 restart


Install Drupal

apt-get install drupal7

Check which version of Drupal is available latest and change version number.

Add Drupal configuration for Apache,

sudo cp /etc/drupal/7/apache2.conf /etc/apache2/mods-enabled/drupal.conf

Restart Apache

sudo service apache2 restart

Open a browser and type the address and proceed with installation process,

http://127.0.1.1/drupal7/install.php

Update Drupal to latest version using Drush
Drush is a command line shell and scripting interface for Druapl.

sudo su 
apt-get install drush

Check new Drupal updates available. Enter inside the Drupal installation place and apply following commands.
cd /usr/share/drupal7
drush up -n | grep available
drush up

Information courtesy: https://help.ubuntu.com/community/Drupal

To know wireless card information in your laptop?

To find wireless card model number is essential to install suitable driver. Execute following command in a terminal to display wireless driver information,

lspci | grep Network


How to know your computer architecture (32 / 64 bit) ?

Open a terminal and type following command,

uname -m

Result

i686 = 32 bit
x86_64 = 64 bit

Another command is

lscpu

Here is the result from my 64 bit PC,

 

How to clear all data in a column in a MySQL database table

In certain cases its essential to clear all data in a particular column in a table.
For example a database name is school
There is a table inside school is student
A column inside school is email 

Column email contains email ids of about 100 students.
Apply following command, if you want to clean all email id entries from email column.

mysql -uroot -p  [enter mysql root password]

You can get mysql command prompt, enter following commands there;

use school;
UPDATE `student` SET `email` = '';
quit;



Now email column inside student table is clean.

How to find CPU architecture information

In certain situations, you have to find PC architecture (32 bit / 63 bit) for various purposes. Here is a simple command to display Linux architecture information.

lscpu

The result is,

Install Whisker menu on Xubuntu 12.04 /XFCE 4

Whisker menu is an application launcher available with XFCE 4. Very easy to find and launch applications with the help of Whisker menu.


Install  Whisker menu on Xubuntu 12.04
Apply following commands,
sudo add-apt-repository ppa:gottcode/gcppa
sudo apt-get update
sudo apt-get install xfce4-whiskermenu-plugin

Remove your default menu and add Whisker menu from panel properties.
Panel > Add New Items > Whisker Menu

View your network information

This command is helpful to collect information about your network details.
Open a terminal and apply following command,

nm-tool

See the result.

Installing Dspace 3.x on Ubuntu 12.04

Installation of prerequisite applications

Open  Applications > Accessories > Terminal and execute following commands. Text in italics are commands to be executed.

sudo apt-get install openjdk-7-jdk
sudo apt-get install tasksel 
sudo tasksel

Select the following packages.
Use space bar for select applications from list.

[*] LAMP server [*] PostgreSQL database [*] Tomcat Java server

 use tab to select OK button and enter. Packages will start to install.
On the way you have to give MySQL root password. MySQL not necessary for Dspace installation.

sudo apt-get install ant maven
 
Create the database user (dspace)

sudo su postgres 
createuser -U postgres -d -A -P dspace

enter password for new role (select a password like dspace) Shall the new role be allowed to create more new roles? (y/n) n

Exit from the promp, type exit

Allow the database user (dspace) to connect to the database [If the following command not open, check the postgresql version number and apply in the command]

sudo gedit /etc/postgresql/9.1/main/pg_hba.conf

Add this line to the configuration file at the end:   

local all dspace md5 

save and close the file 

Restart PostgreSQL : sudo su      enter,

then paste the following line and enter

/etc/init.d/postgresql restart

Create the Unix 'dspace' user, update the passwd, create the directory in which you will install dspace, and ensure that the Unix 'dspace' user has write privileges on that directory:

sudo useradd -m dspace

sudo passwd dspace (enter any password like dspace for the new user dspace)

sudo mkdir /dspace

sudo chown dspace /dspace

Create the PostgreSQL 'dspace' database.
 
sudo -u dspace createdb -U dspace -E UNICODE dspace  

Configure Tomcat to know about the DSpace webapps.
[If the following command not open, check the tomcat version number and apply in the command]

sudo gedit /etc/tomcat7/server.xml

Insert the following chunk of text just above the closing </Host> 

<!-- Define a new context path for all DSpace web apps -->
<Context path="/xmlui" docBase="/dspace/webapps/xmlui" allowLinking="true"/>
<Context path="/sword" docBase="/dspace/webapps/sword" allowLinking="true"/>
<Context path="/oai" docBase="/dspace/webapps/oai" allowLinking="true"/>
<Context path="/jspui" docBase="/dspace/webapps/jspui" allowLinking="true"/>
<Context path="/lni" docBase="/dspace/webapps/lni" allowLinking="true"/>
<Context path="/solr" docBase="/dspace/webapps/solr" allowLinking="true"/>

save and close  the file a

This following  step downloads the compressed archive from SourceForge, and unpacks it in your current directory. The dspace-1.x.x-src-release directory is typically referred to as [dspace-src]. You can also download direct from Sourceforge website.

sudo mkdir /build
sudo chmod -R 777 /build
cd /build
wget http://downloads.sourceforge.net/project/dspace/DSpace%20Stable/3.1/dspace-3.1-release.tar.bz2 

tar -xvjf dspace-3.1-src-release.tar.bz2

cd /build/dspace-3.1-src-release
mvn -U package  
cd dspace/target/dspace-3.1-build
sudo ant fresh_install 
 
Fix Tomcat permissions, and restart the Tomcat server

sudo chown tomcat7:tomcat7 /dspace -R

Restart Tomcat

/etc/init.d/tomcat7 restart

 Make an initial administrator account (an e-person) in DSpace:

/dspace/bin/dspace create-administrator

Test it out in your browser
That is all that is required to install DSpace on Ubuntu. There are two main webapps that provide a similar turn-key repository interface


How to upgrade to Koha 3.12 in Koha Live DVD?

New version of Koha released with bundle of new features.
You can visit the release notes and check new features available with.

http://koha-community.org/koha-3-12-0-released/#more-4403

You can also download illustrated release notes,
http://koha-community.org/files/2013/05/Koha-3.12-release-notes.pdf

If you are Koha Live DVD user, you can easily upgrade to 3.12 version.

http://sourceforge.net/projects/kohalivedvd/

Apply the following command in Applications > Accessories > Terminal

sudo su    [enter the Linux password when it ask, check read me file to find password]
apt-get update
apt-get install koha-common


After upgrading you have to install additional perl modules missing,

Open Koha staff interface and check,  About Koha > Per Modules

You can find missing perl modules highlighted in different colors,

How to install missing perl modules,
Apply following commands in a terminal,

sudo su
sudo cpan


Here is an example to install a perl module called Data::Pagination

install Data::Pagination

The same way, you can install other missing Perl modules.
Now your Koha is upgraded to Koha 3.12 and ready to use.

How to safeguard the panels of Xubuntu Linux for public use computers

Remove and modify the items in panels of Linux desktop is a common problem in Internet cafe's and libraries. A solution is available with Xubuntu Linux to prevent removing the items from desktop panel accidentally by users. 
Follow the steps below,

1. Configure the panels before start the process. Add/remove/edit items from panels.
2. Apply the following command,

sudo cp /home/vimal/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-panel.xml /etc/xdg/xfce4/xfconf/xfce-perchannel-xml/

3. Apply the following command to edit the file.

sudo leafpad /etc/xdg/xfce4/xfconf/xfce-perchannel-xml/xfce4-panel.xml

4. Find following line at the top of the file.

<channel name="xfce4-panel" version="1.0">

Insert # symbol at the start of the line.

5. Copy the following line and paste after the line above mentioned line.

<channel name="xfce4-panel" version="1.0" locked="*" unlocked="root">


 
Save the file. 
 

6. Restart your system.

Information courtesy:  
https://sites.google.com/site/easylinuxtipsproject/xfce#TOC-Safeguard-the-panels-kiosk-mode- 

How to recover gnome-shell

If you found that your gnome-shell task bar missing?
And your desktop seems plain and not able to access applications menu.
You can recover your lost desktop. Follow the steps.

Apply the key combinations, Ctrl + Alt + T 
A terminal will open. Enter the following commands,

sudo su
gnome-shell --replace

You can see that, your desktop panels and menus appear again

Change grahical Ubuntu boot splash into text mode

gedit /etc/default/grub

Find the word "quiet splash".
Remove the word "quiet splash".

Save the file.

Update the grub.

update-grub

How to create Ubuntu Live CD/DVD using Remastersys [Obsoleted]

This tutorial is for creating a Live CD/DVD based on Ubuntu 12.04. You can also try latest version of Ubuntu Live CD/DVD by using the following instructions.

Step 1
Install Ubuntu 12.04 in a PC or inside a Virtual Box application.
Upgrade the system by installing latest packages, apply the following commands,

sudo su
apt-get update
apt-get upgrade

Install the additional applications (e.g. Gimp) for your Live CD/DVD.

Step 2
You can remove following packages to reduce the size of final ISO file.
 apt-get remove libreoffice-help-en-us ubuntu-docs thunderbird smbclient rhythmbox totem deja-dup gnome-orca transmission-gtk

Remove games,

sudo apt-get purge aisleriot gnome-sudoku mahjongg ace-of-penguins gnomine gbrainy


Remove the unnecessary packages deposited in cache using Bleachbit. Otherwise the size of Live DVD will be heavy. Bleachbit can remove lot of junk files and save space. Install Bleachbit using the following command,

apt-get install bleachbit

Open Bleachbit from Applications > System Tools



To use Bleachbit, see the documentation here.

Few more tips too make your Live DVD good,

Disable Apport to prevent unwanted system messages.

Open following file and fine the entry enabled=1 change to enabled=0.

sudo gedit /etc/default/apport

You can change boot splash to text mode. Open following file

gedit /etc/default/grub
 
and find following line,

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Remove the entry "quite splash", save file and close.


Step 3
Installation of Remastersys in Ubuntu 12.04. Apply the following commands.

sudo su
wget -O - http://www.remastersys.com/ubuntu/remastersys.gpg.key | apt-key add -

gedit /etc/apt/sources.list


Add the following lines in the file, save and close.

#Remastersys Precise
deb http://www.remastersys.com/ubuntu precise main


Update the package repository and install Remastersys

apt-get update
apt-get install remastersys remastersys-gtk

Remastersys will appear in Applications > System Tools > Administration
  
See the screen shots below,

Main screen of Remastersys.


You can assign a name for Live DVD.


You can export user settings to Live DVD. It means, you can assign an inbuilt user name and password for DVD.

You can click on appropriate buttons to build Live DVD. You need Internet connection to run Remastersys. Certain packages to be installed from Internet to build the Live DVD. The output will be in .iso format, you can locate it from /home/remastersys. Burn the .iso file in a DVD and boot from computer.

How to install Gnome Classic desktop in Ubuntu 12.04

Execute the following command in a terminal,

sudo apt-get install gnome-session-fallback

Log out and select Gnome Classic from login session.