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Before GEANT4 installation, it's important to proceed some configuration and tests to be sure the basic pre-requisites exists. For instance, gcc, openGL, cmake.
I'll change some console colors. This is cosmetic stuff and it's not important.
Just like old IBM terminal or those first PCs.
Logon as "super user". The command for that is "su". The password is that one I told you to write down in the previous video.
I'll set geant4 up to be a "sudoers" user. This will give geant4 the privileges I need to make additional configuration and to install some pieces of software.
The file that need to be modified is "sudoers" inside /etc directory.
Listing the /etc content lookin for sudoers file.
Here is it and it is setup for reading only by its owner (root) and its group (root). I'll modify this in order to be able to change the file content and save it.
This can be made using the "chmod u+w sudoers" command line. This will give to its owner permission to be written. (u = user; w = write)
Let's list again and see the result of the previous command.
Now we can see that the file has permission to be written by its owner.
Editing the file using the "nano" file editor. You can use any, including a graphical one like "gedit".
Going down to the place I'll include geant4 ...
For a sake of simplicity and without any further consideration regarding security good practices, I'll do the same configuration as the root one.
"CTRL-O + ENTER" to save the file and "CTRL-X" para exit the editor.
Setting back the sudoers file original permissions.
Type "exit" to quit "super user" mode.
Just to check if I really am in my "home" directory.
Let's check if the C/C++ compiler is installed. (gcc = GNU C Compiler).
It's not installed.
The default package manager for SLC is "yum". Let's use it to verify some information about gcc.
This label "Available Packages" tell us that this package is available for installation but it isn't actually installed. It's in the repository that we've set during the SCL 6.3 installation in the previous video.
Another way to do this is using the graphical environment.
Just type what you are looking for to search for the package.
The compiler entry doesn't have its "check box" checked. This means it's available but not installed, as we saw via console.
I'll check the packages I want to install.
It can be seen that there already is some installed packages as some needed gcc libraries. (it's not allowed to chance their status neither to install nor to uninstall).
Let's see this same thing via console ...
It can be seen that "libgcc" is shown as "Installed Packages".
The same thing is shown about "libstdc++". Both "libgcc" and "libstdc++" are need for our purposes.
Just for curiosity, let's see this via console.
Let's proceed the installation via graphical environment.
It's shown that 10 additional packages need to be installed. They are dependencies needed for the packages we choose to install.
It can be seen that the packages are being downloaded from the internet.
While gcc installation is in progress, Let's verify if "cmake" is already installed. GEANT4 need cmake since version 9.5.
Agian, as for gcc, cmake is available, but not installed.
The gcc installation is still in progress ...
We choose to trust fnal.gov website (Fermilab laboratory).
Installation still in progress ...
gcc installation finished!
Let's check the gcc installation via command line.
Ok! gcc is now installed.
Let's test it! Ok! Version 4.4.6
Let's install cmake then!
I'll install "cmake" via console using "yum". The command line is: "yum install cmake".
This kind of procedure can be only made by the "root" user or by one of the "sudoers".
As geant4 is already a "sudoers", I'll use de command "sudo" before the "yum".
Confirm (y) to proceed the download for the installation. Version 2.6.4.
The installation has finished. Let's test the cmake command.
Now, cmake can be seen also via graphical environment.
It is also important to have installed the "openGL" driver. It is used by GEANT4 to visualize some simulations aspects.
The openGL driver can be installed as "opengl*" or as "mesa*". Remember, the "*" character means any character or set of characters.
Let's use "yum" to get information about "opengl" driver.
opengl is not present.
Let's check if openGL is present by mesa.
The driver mesa (openGL) is installed.
The "yum" program use with its "list" argument lists all packages.
The previous command can be used along with a filter programa like "grep" to get only the meaningful result.
"yum list" lists all packages. The vertical bar "|" (pipeline) is the way we pass the results to the "grep" program. The "opengl|mesa*" is the grep's argument and tell it to filter anything that contains "opengl" or "mesa*". In this case the character "|" means "or".
Ops! Nothing in the list. That's because I forgot to use the "-E" option for the grep.
Now it's ok.
A last check in the mesa driver (openGL).
Thank you!