Removing annoying console beeps

In order, to remove the beep sound of your linux console just type the following command, in your console (in the directory /home/$your_user)

$echo 'set bell-style none' >> ~/.inputrc

How to synchronize Multiple Dropbox Accounts in your computer

[CONTEXT]
You have multiple accounts in dropbox. (Assume that you have alredy install dropbox on your computer).

[WHEN]  
You want to synchronize all your dropbox account files in your computer at the same time.

[HOW]

• Create the alternative folders for your additional account, for example

         $ mkdir ~/.dropbox-mte
           $ mkdir ~/dropbox-mte

• Run from a terminal the following command

        $ HOME=$HOME/.dropbox-mte /usr/bin/dropbox start -i

• Configure your account and make as default directory ~/dropbox-mte

• Create a file to launch the new instance of the dropbox deamon for example,

            DropboxAltStarter.sh

           #!/bin/bash
           HOME=$HOME/.dropbox-mte /usr/bin/dropbox start

• Executable permissions 

           $chmod 755 ~/DropboxAltStarter.sh

• Include DropboxAltStarter.sh in your starter.

"Go to System -> Preferences -> Startup Applications. Click Add and          include the following:
Name: 2nd instance of Dropbox
Command: /home/Username/DropboxAltStarter.sh
Click Ok."

  
[SOURCE]
http://www.maketecheasier.com/run-multiple-dropbox-accounts-in-mac-and-linux/2010/05/24

Installing Latex packages in your home directory

  
[CONTEXT]
Without root access, we cannot put the packages or Latex's style files into the directory /usr/share/texmf/


[WHEN]
We want to install Latex package or style files for all our Latex documents but we are working in computers that we do not have root access.



[HOW] 
Create a private tex hierarchy

$mkdir  $HOME/texmf/tex/latex

Put in this directory all your class, style, and package Latex files.
For custom bibtex style files, create the directory texmf/bibtex/bst

$mkdir $HOME/texmf/bibtex/bst

and put your bst files into it.


After any modification of the $HOME/texmf directory, run the command:
$texhash

Source: http://www.math.uiuc.edu/~hildebr/tex/tips-customstyles.html

Installing the Nvidia Kernel module

As root type

# apt-get install module-assistant nvidia-kernel-common

# m-a auto-install nvidia-kernel${VERSION}-source

# apt-get install nvidia-glx${VERSION} 

and reboot

Source: http://wiki.debian.org/NvidiaGraphicsDrivers

Normal users can't connect to X

Suddenly, my user  can't login into X sever, and I got the following error in the file /var/log/Xorg.0.log

[   157.920] (EE) Error compiling keymap (server-0)
[   157.920] (EE) XKB: Couldn't compile keymap
[   157.920] (EE) XKB: Failed to load keymap. Loading default keymap instead.
[   157.944] (EE) Error compiling keymap (server-0)
[   157.944] (EE) XKB: Couldn't compile keymap
[   157.944] XKB: Failed to compile keymap
[   157.944] Keyboard initialization failed. This could be a missing or incorrect setup of xkeyboard-config.
[   157.944]

Just login in a console as root (e.g. atl+f1) and type

#chmod ug+rwx,o+rwt /tmp

then reboot

Source:

http://forums.debian.net/viewtopic.php?f=6&t=47031

http://forums.debian.net/viewtopic.php?f=6&t=47759

Adding directories to your PATH variable

Edit your .bashrc as user and add the line:

export PATH=$PATH:/path/to/directory

Enable programmable completion for user

Enable programmable completion for a user:
First install bash-completion package, as root user type

aptitude install bash-completion

and, just add the following lines to the /home/$USER/.bashrc (as $USER)

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

also the root user can have this feature, adding the same lines above in /root/.bashrc

root with X access

Using Debian Squeeze and others older versions, the root cannot execute X programs from a x-console (like kde-konsole or gnome-terminal).

To allow this just edit your root's .baschrc and add this line

export XAUTHORITY=/home/$SOME_USER/.Xauthority

where  SOME_USER is replaced by a user with X access.

Jacksense in Debian

In Debian squeeze the jacksense in my laptop didn't work. Solution: I installed the latest Alsa driver. In Debian wheezy works fine.
Source: http://blog.netflowdevelopments.com/2011/11/19/switch-from-ubuntu-to-debian-and-now-jacksense-doesnt-work/

Nvidia Optimus in linux

This Nvidia Optimus technology is a whole new ball game for me, my laptop has two graphics cards, and depending on the requirements, it uses one or another, luckily there is a Linux project called Bumblebee to make it work
To install it, add this next lines to /etc/apt/source.list

#bumblebee Nvidia optimus
deb http://suwako.nomanga.net/debian sid main contrib
deb-src http://suwako.nomanga.net/debian sid main

Execute the following commands as root

wget -O - http://suwako.nomanga.net/suwako.asc | apt-key add -

aptitude update 

aptitude install nvidia-glx linux-headers-$(uname -r) nvidia-kernel-dkms

sudo update-alternatives --set glx /usr/lib/mesa-diverted 

aptitude install bumblebee bumblebee-nvidia

adduser $USER bumblebee ($USER is your regular X user)

reboot

Make a test

optirun glxgears -info

Source:

http://bumblebee-project.org/

https://wiki.debian.org/Bumblebee#Installation

http://suwako.nomanga.net/