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Always we use $sudo rpm -ivh rpm_file to install a package, but how to uninstall it?

1.If you know the name of your package which you want to uninstall, you just can use the following command to complete:
$sudo rpm -e package_name .rpm

Then the package will be uninstall from your computer.

2.When you forget the name or you just remember a part of the name, you can uninstall it following the steps:
$rpm -qa | grep -i key_words_of_package_you_want_uninstall

Then you will get a list of exact package names in which include the key words, then run
$sudo rpm -e exact_package_name

to uninstall it.

i.e.
I want to uninstall qt-x11, and I forget the exact package name, then:
$rpm -qa | grep -i qt
qt-4.6.2-28.el6_5.i686
qt-x11-4.6.2-28.el6_5.i686
qt-sqlite-4.6.2-28.el6_5.i686

$sudo rpm -e qt-x11-4.6.2-28.el6_5.i686

and the qt-x11 will be uninstalled.

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The stardict is a good tool for translating.

DOWNLOAD
1.Download stardict from the following link:
http://pkgs.org/search/?keyword=stardict

Choose the proper version and download it. My information is 2.6.32-431.11.2.el6.i686, and I download stardict-3.0.2-1.el6.i686.rpm.

I suppose your download location is ~/Downloads/stardict-3.0.2-1.el6.i686.rpm.

INSTALL
1.$sudo rpm -ivh stardict-3.0.2.el6.i686.rpm
Then you might get the error messages like:
warning: stardict-3.0.2-1.el6.i686.rpm: Header V4 DSA/SHA1 Signature, key ID fac8d3c0: NOKEY
error: Failed dependencies:
espeak is needed by stardict-3.0.2-1.el6.i686.rpm
libespeak.so.1 is needed by stardict-3.0.2-1.el6.i686

2.Missing dependencies, we can install it with yum which can help us analysis and install dependencies.
$sudo yum localinstall stardict-3.0.2-1.el6.i686

Then the missing dependencies will be automatically installed.

3.The stardict has been installed successfully up to now. It is better to install the local dictionaries. Go to the link below:
http://abloz.com/huzheng/stardict-dic/

Then get the dictionaries you want, and install them as the page says(The installation method is given on the top of the page).

USAGE
You can launch stardict just by command:
$stardict &

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When installing VirtualBox on CenOS 6.5, I get some errors that indicates losing qt dependencies.

The error messages like these:

libQtCore.so.4 is needed by VirtualBox-4.3-4.3.10_93012_el6-1.i686
libQtGui.so.4 is needed by VirtualBox-4.3-4.3.10_93012_el6-1.i686
libQtNetwork.so.4 is needed by VirtualBox-4.3-4.3.10_93012_el6-1.i686
libQtOpenGL.so.4 is needed by VirtualBox-4.3-4.3.10_93012_el6-1.i686

It’s easy to solve it by type a command:

$sudo yum install qt

 

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In my case, I use VirtualBox-4.3-4.3.10_93012_el6-1.i686.rpm on CentOS 6.5.

DOWNLOAD VIRTUALBOX
1.Go to website to download the proper one.
https://www.virtualbox.org/wiki/Linux_Downloads

2.Go to website to download Extension_pack.
https://www.virtualbox.org/wiki/Downloads

You can find the download link which like this on the page:
VirtualBox 4.3.10 Oracle VM VirtualBox Extension Pack All supported platforms.The Extension Package will allow you to use usb in VirtualBox.

INSTALL

1.Because Virtualbox will compile the kernel modules. So we are supposed to install the DKMS(Dynamic Kernel Module Support), which will simplify the steps of update kernel modules. Use the command below to install it(make sure you have set the rpmforge source):
$sudo yum –enablerepo rpmforge install dkms

2.Install the virtualbox with the follow commands:
$sudo rpm -ivh VirtualBox-4.3-4.3.10_93012_el6-1.i686.rpm

If not install the libSDL, you will get a message that you should install it. Install it with the commands:
$sudo yum install SDL

If you have the Qt dependencies, you should go to this page to solve the problem: http://blog.xinspace.name/?p=660

and then try the first command to install VirtualBox again.

3.Install the Extension Package you download before. Enter the folder of the Extension package, and use the commands:
$nautilus ./ &

It will open the window of this folder.

Double-click the Extension Package file and it will guide you install the package.

4.Add all users who will use virtualbox to the vboxusers group:
$sudo usermod -a -G vboxusers your_user_names

5.Then you can open the VirtualBox with:
$VirtualBox &

And you can use it.

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Favicon, in turn, is the shortcut of favorites icon, which will be displayed by Internet Browser to distinguish different website. So a personal favicon represents your own style.

Usually favicon is a picture whose size is 16 * 16 pixels, storing in the root folder named after .ico.

So, the first step is that you must prepare a picture, after that, you can go to the website:favicon.co.uk to make your own favicon.ico with the picture prepared before.

Then download the favicon.ico via the download link, which under the button named Generate Favicon.

The last, you should replace the original favicon.ico with your new favicon.ico using the following commands:

$sftp username@hostname

$put your_own_favicon_ico favicon.ico

The username, hostname above are the names of your server ip address or name which contains your website. You should log in your server to complete replacing.

The your_own_favicon_ico is the absolute path of your new favicon.ico downloaded before.

When the two commands above completed, you have finished all the steps making your own favicon.ico for your website. Then just cleaning browser’s cache and history, opening your website again, you will find your own favorites icon on your browser’s tab.

 

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CentOS can not read or write ntfs format, so if you insert your hard disk into the computer, Centos will tell you “uable mount”.

The ntfs-3g is the solution of this problem. The ntfs-3g driver is an open source, GPL licensed, third generation Linux NTFS driver. It provides full read-write access to NTFS, excluding access to encrypted files, writing compressed files, changing file ownership, access right.

INSTALL
1.Download the latest rpmforge-release rpm from:http://apt.sw.be/redhat/el6/en/i386/rpmforge/RPMS/rpmforge-release-0.5.2-1.el6.rf.i686.rpm

you can use the command:
wget http://apt.sw.be/redhat/el6/en/i386/rpmforge/RPMS/rpmforge-release-0.5.2-1.el6.rf.i686.rpm

2.Install rpmforge-release rpm:

#rpm -Uvh rpmforge-release-0.5.2-1.el6.rf.i686.rpm

3.Install fuse-ntfs-3g rpm package:

#yum install fuse-ntfs-3g

After completed, you can try your hard disk again.

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If we want to delete something in linux, we use the command ‘rm’, but it’s dangerous, because this command will delete it(them) from our hard disk, meaning we can not restore it when we want to. So for safe, we can move our files we want delete to trash bin.That’s what trash-cli does.

You can also use script to replace trash-cli, i.e. move $1 ~/.local/share/Trash. However, I still suggest you install trash-cli.

There are some problems when we install trash-cli on centos using the command:

#yum install trash-cli
The Yum will tell you no valid packages. You can follow the steps below and succeed!

INSTALL

1.Download the latest rpmforge-release rpm from : http://apt.sw.be/redhat/el6/en/i386/rpmforge/RPMS/, if your arctecture is x86_64, then go to : http://apt.sw.be/redhat/el6/en/x86_64/rpmforge/RPMS/

you can use the command:
wget http://apt.sw.be/redhat/el6/en/i386/rpmforge/RPMS/rpmforge-release-0.5.2-1.el6.rf.i686.rpm

2.Install rpmforge-release rpm:

#rpm -Uvh rpmforge-release-0.5.2-1.el6.rf.i686.rpm

3.Install trash-cli rpm package:

#yum install trash-cli

You can learn it with command: man trash-list

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OpenCV(Open Computer Version), strong open source library, can process the images,videos and others.

DOWNLOAD & INSTALL

1.Download with the command:
$wget http://jaist.dl.sourceforge.net/project/opencvlibrary/opencv-unix/2.4.8/opencv-2.4.8.zip

I suppose your download location is ~/Downloads/opencv-2.4.8.zip

2.Unpack the file
$unzip opencv-2.4.8.zip

You will get a folder named opencv-2.4.8

3.Move the folder to your workspace
$mv opencv-2.4.8 path_of_your_workspace

4.Configure and install
$cd path_of_your_workspace/opencv-2.4.8/
$mkdir release
$cd release
$cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local ..

cmake is a command, if bash says “bash: cmake command not found”, you can type $type cmake to find the command, and replace the cmake with your cmake absolute path.

$make

When execute the commmand $make, the output may like this

###output start##########
CMake Error at /home/xinspace/Item/opencv-2.4.8/cmake/cl2cpp.cmake:50 (string):
string does not recognize sub-command MD5

make[2]: [modules/ocl/opencl_kernels.cpp] Error 1
make[1]: [modules/ocl/CMakeFiles/opencv_ocl.dir/all] Error 2
make: *** [all] Error 2

######output end##########

Maybe the cmake version is too old(2.6), try 2.12 installed from source.You can get the guide of installing the lastest version of cmake from source by following this link: http://blog.xinspace.name/2014/04/15/install-cmake-on-centos-6-5/
After update your cmake, you should go back to step 4 cmake command line(the line under $cd release).

$sudo make install

Then you finish the guide.

ORIGINAL ARTICLE:http://docs.opencv.org/doc/tutorials/introduction/linux_install/linux_install.html#linux-installation

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Qt is a cross-platform application and UI framework for developers using C++ or QML, a CSS & JavaScript like language. Qt Creator is the supporting Qt IDE.

Qt now includes QtCreater and QtDesign.

DOWNLOAD & INSTALL

1.Go to the website: http://qt-project.org/downloads to download Qt5.2, i.e.Qt 5.2.1 for Linux 32-bit or Qt Online Installer for Linux 32-bit
As it says, this file includes QtCreater & QtLibrary.
I suppose your download location is ~/Downloads/qt-opensource-linux-x86-5.2.1.run

2.Change the permission of the qt file.
$chmod +x qt-opensource-linux-x86-5.2.1.run

3.Execute the qt file
$sudo ./qt-opensource-linux-x86-5.2.1.run

And it guides you finish the installation.

USAGE

You can input the command $/opt/Qt-5.2.1/Tools/QtCreater/bin/qtcreater & to start QtCreater or goto the applications list and click the QtCreater icon.