In ubuntu 10.04 distribution package there is one software i.e installed by default(In accessories) called- “Take Screenshot” with some basic features,can be used to take screenshot.Suppose you want to take screenshot for some selected region then you start annoying with this.One week ago,while I was messing around software center,a new software Ksnapshot came into the mind.I installed it and Now I think this is what I was looking for weeks.Ksnapshot is an excellent software I recommend you to use it for taking snapshots and enjoy.It is better not only in features but it is also more stable then the “Take Screenshot”.
gbrainy : A logic game to train your brain with fun
There are many logic games available in ubuntu.To install just go to software center/games/Puzzles and install it in single click.Today I am going to introduce with an excellent logic game that have many-many features and in my point of view it is the best one.The another exciting point is that in ubuntu 10.04 it will be installed on your system by default.Although some other default games are removed fr0m the default package but you can find those games in software center or synaptic manager.
Important features of gbrainy :
- Logic puzzles : test your reasoning skills.
- Mental calculation : simple arithmetic operations to test your mental calculation abilities.
- Memory trainers : Improve! your short term memory power.
- verbal analogies : Examine your verbal aptitude.
One important point is that gbrainy will give you the final result with detail analysis.
By default you can’t login as root in ubuntu 10.04 or other linux distribution due to the security policy of linux.Suppose you have logged in as root in ubuntu and by mistake you did something wrong then your system may be crash.But administrative power is required in some cases such as in installing some programs to solve file permission problem while working on file system.That’s why there is a simple solution and is sudo command.hence you can do administrative task or run administrative commands followed by sudo.Hence in this method you will have to work in command line interface.So in the case if you don’t know much more about ubuntu commands OR you feel irritating in doing some administrative task fr0m command line then you can enable the root login fr0m the login menu and run as a root.
Hence It is very simple to enable root logging in graphical or GUI mode, just follow these simple steps –
step1. Open the bash terminal.
step2. Type the command sudo passwd root.First it will ask for the user password.Enter your current-user session password and and hit enter.
ubuntuuser@ubuntuuser-desktop:~$ sudo passwd root
[sudo] password for ubuntuuser:
step3. Then it will ask for new password.Enter a new password twice.This is the password you will use this in future for logging as root.
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
step4. To check whether it is working or not just logout fr0m the current session.At login prompt,choose other as a user account.Next, in the place of username write root and the password you just defined in the above step.
step5. that’s all..I hope your work is done.
NOTE : If you logged in as root then you must be careful about the each activities.After finishing the administrative task you should return to the normal mode.
You may like this post : A simple tutorial to learn- how to secure from internet threats.
In early days it was difficult to manage the permissions for different users in a multiuser operating system that may be a client or server;suppose every user has a power of a superuser or root then any one of them may be misused the system either intentionally(If the user is smart) or ignorantly(If the user is a beginner one).Hence the simple solution of this problem is to limit the power for every users according to their need so that they can do simple tasks normally but in case of any administrative task root power is granted for small period(usually five minutes)by using the sudo commands.In sudo su stands for superuser and do means do(as usual).Hence sudo is mostly used by a permitted user for taking the permission to execute some commands as a another user or superuser, according to the information specified in sudoers file.Suppose the user that is invoking a command using the sudo power, is root then there is no need to enter user password.By default authentication is required and the user password is required; the user may use the sudo power again for short period of time(5-15min).So sudo is very useful in finishing some administrative task by a simple user.Now we are going to learn something more about the sudo commands.
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).
Credit : Todd C. Miller
Now e-books are becoming more popular and useful.When you have a number of e-books on different categories then it is difficult to keep track of them.That’s why you need a library manager so that you can manage your collections more effectively.I am going to introduce you with an open source software which is a complete solution to the e-book library management.
CALIBRE : An open source and cross platform e-book library manager which can be used to view,catalog and convert e-books in all the common available formats of e-book ,e.g pdf,LRS,txt.It can also convert the simple format information into e-books to make the reading easier.
supported input – e-book formats are :
MOBI , LIT , PRC, EPUB, ODT, HTML, CBR, CBZ, RTF, TXT, PDF, LRS.
Supported Opeating systems are :
Linux, Wndows, OS X