Recently Django version 1.4 has released but in Ubuntu 12.04 beta or 11.10 or any older versions you can’t get the latest version from the official package repository (In 12.04 Beta 2, the latest version was 1.3). So if you want to try latest version of Django on Ubuntu, then you must install it either from a PPA or manually from source code.

How to Install Django in Ubuntu

Django 1.4 requires Python 2.5 or later but you shouldn’t wory about that because in Ubuntu, Python 2.7 is installed by default. Open a terminal and execute these commands (you need sudo privilege, just enter your login password) :

wget "http://www.djangoproject.com/download/1.4/tarball/"
tar xzvf Django-1.4.tar.gz
cd Django-1.4
sudo python setup.py install

step1: In your browser,open a new tab.

step2: Now type(In URL Field i.e in address bar of the browser)
javascript:(airthmatic expression you want to evaluate);
(It will give you output in body of the browser)

You can also use another method for getting output in an alert window.
type
javascript:alert(your arithmetic expression);
e.g
write the following line in the address bar of your browser.(Don’t forget to end the line with semicolon)
javascript:(24+1204-450*102);

step3: You will get the output like this in the browser’s body(top left corner).
-44672

Finish.

Syntax of the sudo commands :

It is very simple..just use the word sudo before the actual command and hit enter.Then it will ask for the users password ..enter the password after the authorization process the commands will execute.e.g I am trying to execute commands1(installing a package using apt-get).

user840@user840-desktop:~$ sudo commands1
[sudo] password for user840:
Reading package lists… Done
Building dependency tree
Reading state information… Done

….and so on the execution will complete.

Options in SUDO :

-A : Using this option the another helper program(It may be in graphical format) is called and executed to read the password of the user and output the user password to the canonical output.

-u user : this option tells the sudo to run the target command as a user instead of root(which is default case).You may use UID rather than username by using UID followed by ‘#’.i.e #uid.
-a : It is used by the sudo to use the special authentication type for the validation of the user according to the permission settings stored in /etc/login.conf.
This option is is used only in the system having the support with BSD authentication mechanism.

-b : Specifying -b(background) with the sudo command simply means to order the sudo that “run the target command in background”.

-p prompt : By using -p (prompt) one can easily customize the password prompt.So using some ‘%’ escapes(e.g %H,%h,%p) you may use any other prompt rather then the default one.

Although there are many other options available but you can easily find out in your bash shell.just type info sudo and hit enter.

Environment Variables :

here are the some environment variables used by the sudo.

USER : Set to the current user.By default its value is equal to root if -u option is not specified.

SUDO_UID : user ID of the user who used the sudo.

SUDO_USER : Set to the login of the permitted user who is using sudo.
Go to your bash terminal for the details about the more environmental variables(info sudo OR man -k sudo OR help sudo).

#  date +%r

So now that I can display the current time, I just need to figure out how to continuously update the information in order to create a terminal clock. I’m going to do that by using the echo command to display the output of the date command. By using some options with echo so that the output gets over-written, and placing that command in an infinite loop, I can display a simple clock in the terminal.

So here’s the command:

#  clear; while true; do echo -e \\b\\b\\b\\b\\b\\b\\b\\b\\b\\b\\b\\b`date +%r` \\c ; sleep 1; done

Take note of the back-ticks around the date command. That tells the echo command to display the results of the date command. The “\\b” enters a backspace into the command and “\\c” tells echo not to enter a newline character. The number of \\b’s needed will depend on the output time display format for your locale, so adjust this up or down as needed.

wget http://www.truecrypt.org/downloads/truecrypt-4.3a-ubuntu-7.04-x86.tar.gz
wget http://bockcay.de/stuff/programs/forcefield/forcefield_current_all.deb

sudo apt-get install python-crack python-pexpect cracklib2

tar xfz truecrypt-4.3a-ubuntu-7.04-x86.tar.gz
sudo dpkg -i truecrypt-4.3a/truecrypt_4.3a-0_i386.deb
rm -rf truecrypt-4.3a truecrypt-4.3a-ubuntu-7.04-x86.tar.gz

sudo dpkg -i forcefield_current_all.deb

$ tar -xzvf ettercap-version.tar.gz

$ make

$ make install

To install in Ubuntu simply click here within firefox or:

sudo apt-get install ettercap-gtk

2. After installing, you need to uncomment some code to enable SSL dissection. Open up a terminal window and type “nano /usr/local/etc/etter.conf”, without the quotes. Scroll down using your arrow keys until you find this piece of code:

if you use iptables:

*  # redir_command_on = “iptables -t nat -A PREROUTING -i %iface -p tcp -dport %port -j REDIRECT -to-port %rport”

*  # redir_command_off = “iptables -t nat -D PREROUTING -i %iface -p tcp -dport %port -j REDIRECT -to-port %rport”

You need to uncomment the last two lines.

*  redir_command_on = “iptables -t nat -A PREROUTING -i %iface -p tcp -dport %port -j REDIRECT -to-port %rport”

*  redir_command_off = “iptables -t nat -D PREROUTING -i %iface -p tcp -dport %port -j REDIRECT -to-port %rport”

3. Press CTRL+O, press enter to safe the file and then press CTRL+X.

4. Start Ettercap and click on Sniff > Unified Sniffing > type in your wireless interface and press ok.

5. Press CTRL+S to scan for hosts

6. Go to MITM > ARP poisoning, select sniff remote connections and press ok.

7. Now you (and your neighbour!) can start sniffing! Press start > start sniffing. Walk to another computer on your network and open up paypal or any other site where you need to type in an username/password (gmail, hotmail, digg.com, etc.). All credentials will appear on the computer running Ettercap!

8. When you’re done, don’t just close Ettercap, but go to Start > Stop Sniffing, and then go to MITM > Stop mitm attack(s).

But how does all this stuff work?

Look at the following scheme:

Normally when you type in a password, host 1 (your computer) directly connects to host 2 (your modem or router). But if someone launced Ettercap on your network, host 1 isn’t sending it’s passwords to host 2, but to the Attacking host, the host that’s running Ettercap! The attacking host sends everything to Host 2. This means that host 1 isn’t noticing anything! Exactly the same happens with everything that host 2 is sending. Host 2 doesn’t send packets directly to host 1, but forst to the attacking host.

Open Terminal & type :

sudo apt-get install fuseiso

If you are in firefox and have apt-url installed click here to install with one click!

Then lets add ourselves to the fuse usergroup
sudo adduser myusename fuse
If you were not in the fuse group you will need to log off, then back in right now.
Now lets create ourselves a fuseiso folder to mount our iso
sudo mkdir /media/fuseiso
Now we just grabbed an iso off the net, so lets mount it!
sudo fuseiso myisofile.iso /media/fuseiso
Ok now the iso is mounted and we can use it like its a cd/dvd
Nautilus/cd your way to /media/fuseiso and the files from the iso will be mounted readonly.

More information on fuseiso can be found here

Photivo tries to provide the best algorithms available; even if this implies some redundancy. So, to my knowledge, it offers the most flexible and powerful denoise, sharpen and local contrast (fake HDR) algorithms in the open source world. (If not, let’s port them ) Although, to get the desired results, there may be a quite steep learning curve .

Photivo is just a developer, no manager and no “Gimp”. It is intended to be used in a workflow together with digiKam/F-Spot/Shotwell and Gimp. It needs a quite strong computer and is not aimed at beginners.

Installation:

Dariusz Duma provides a PPA for Ubuntu with frequently updated that also includes Photivo’s dependences.
Using following commands to add PPA and install Photivo:

sudo add-apt-repository ppa:dhor/myway
sudo apt-get update
sudo apt-get install photivo

Features:
16-bit internal processing, color managed with LCMS2.
Gimp workflow integration (import and export)
Works with RAWs and Bitmaps (8 bit bitmaps are transformed and processed with 16 bit, which usually gives better results).
CA correction, Green equilibration, line denoise, badpixel reduction, wavelet denoise, median filters on RAW data.
Demosaicing: Bilinear, VNG, VNG4, PPG, AHD, DCB, mod. AHD, VCD, LMMSE, AMaZE (needs work!).
RGB, R, G, B, L*, a*, b*, Texture, Detail, Hue, Saturation, L* by Hue, Base curve.
Tonemapping (Reinhard 05 (RGB Brighten), Fattal et al. (Dynamic range compress)).
Several local contrast filters (HiRaLoAm (Local contrast), texture contrast, local contrast stretch).
Sharpen (Edge avoiding wavlets, USM, Highpass, Inverse diffusion, Wiener filter, Gradient sharpen).
Denoise, seperately on Luminance and Color (Edge avoiding wavlets, GreyCStoration, Wavelet, Masked bilateral, Pyramid).
Adaptive saturation.
Film grain simulation.
Black and white conversion.
(Split) Toning.
Cross processing.
Gradual overlay (like Cokin filters).
Vignetting.
Softglow / Orton.
Texture overlay (external texture)

Currently, FreeCAD can import and display CAD models in IGES, STEP, and BRep formats and meshes in STL, BMS, AST and Wavefront OBJ formats. Editing and modeling features are currently somewhat limited.

More about FreeCAD: http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Main_Page

FreeCAD is available in Ubuntu Software Center, but it may be old. Download latest version here

There are two types of links

symbolic links: Refer to a symbolic path indicating the abstract location of another file
hard links : Refer to the specific location of physical data.

How do I create soft link / symbolic link?

To create a symbolic link in Unix or Linux, at the shell prompt, enter the following command:
ln -s {target-filename} {symbolic-filename}

For example create softlink for /home/gurjot/Desktop/syllabi.pdf as /home/gurjot/study/syllabi1.pdf, enter the following command:
ln -s /home/gurjot/Desktop/syllabi.pdf  /home/gurjot/study/syllabi1.pdf
ls -l /home/gurjot/Desktop/syllabi.pdf

Output:

lrwxrwxrwx 1 gurjot  gurjot   16 2011-08-12 22:53 syllabi1.pdf -> /home/gurjot/Desktop/syllabi.pdf