How to install Celestia in Ubuntu 18.04 or Debian 9

Latest Debian based distros don't include Celestia in their repositories and you need to compile the software to enjoy it.

Just need to type the following commands in your console (Ubuntu and derivates distros):

sudo apt-get install libglew-dev libjpeg-dev libpng-dev libtheora-dev libgl1-mesa-dev libeigen3-dev libfmt-dev qtbase5-dev qtbase5-dev-tools and libqt5opengl5-dev freeglut3-dev libgtkglext1-dev liblua5.2-dev git
git clone https://github.com/CelestiaProject/Celestia
cd Celestia/
mkdir build
cd build/
cmake .. -DENABLE_QT=ON
make
sudo make install

If you use Debian type first su - and then type the same commands as Ubuntu case but don't type sudo

PCem, old PCs emulator for GNU/Linux

PCem, is an old PCs emulator than simulate certain old machines like los Amstrad PC for example, this is not emulate only DOS system like DosBOX do so good.

Let's go to install and configure it.

Download and instalation

1. Install all the necessary libraries:
   sudo apt-get install libsdl2-dev libopenal-dev libwxbase3.0-dev libwxgtk3.0-dev automake
2. Download  latest available version of code from bitbucket.
3. Create a folder and uncompress in it:
   mkdir pcem
   cd pcem
   tar -zxvf ../PCemV14Linux.tar.gz
4. Compile and install:
   sudo chmod +x ./configure
   ./configure --enable-release
   make
   sudo make install

Configuration

Run emulator a first time:

pcem

You get an error because you haven't any BIOS but .pcem folder will be created in your $HOME with all the folder structure to add all the files you need:

Folder	Contents
configs	Each system configuration file.
logs	emulator logs (errors and warnings).
nvr	nvr
roms	ESSENTIAL: the roms you need for each system. This folder contains a folder for each PC type to emulate.
screenshots	Screenshots.
Other folders	You can create HD and DSK folders to add HD or floppy images for example.

If we have a configuración of a Windows pcemu for example, we need to copy configuration in .pcem folder.

We can change some things in emulation while machine is running clicking with right button into the emulation window.

Or we can use dialog boxes we can see when pcem start with any roms files included. This allow us add more configuration profiles or change the ones we have.

Important: check that all configuration files have the right path.

SuperTuxKart: unlock all tracks and karts

SuperTuxKart is a race karts game similar as Mario Kart and one of my favorite games because it's addictive and allow a lot of interesting things.

Now we see a tick to unlock all tracks and karts, we need edit a file with and editor than keep the original format of the file (I use jEdit).

This is the full path of the file:

$HOME/.config/supertuxkart/0.8.2/players.xml

we need change these strings:

true ► false

none ► hard

And that's it, you can already enjoy all the karts and tracks, including those that are blocked without needing to get the milestones.

Open alternatives to privative software (XII): GIMP, the graphics editor

You need GNU/Gimp if you need edit a photo or any image.

The GIMP is a very powerfull tool, at least as much as the most well known and you needn't pay a lot of money for a licence and you have the guarantee than it's open source.
Anyway, as any other software, you need a good manual or a course to learn of the possibility.

Some of its feautures:

• Multisystem: there are Windows, Mac (now full native), GNU/Linux y much more other unixes versions.
• Most GNU/Linux distros includes GIMP installed of included in their official repositories.
• Can import from or export to almost all graphics format.
• This is open source and also free software, you needn't pay expensive licences.
• You can do a lot of things with layers, make an animated GIF, images for different scenarios, etc...

Sice 2.8.x version was launched you can work in an unique window or not.
This version requires a pentium 4 processor at least and Windows version must be runned al least in Windows XP with service pack 3.

If our computer hasn't the minimal requirements (our PC must be older than 15 years old) we can use the older versions. They have most of the feautures with less requirements.

You can see professional possibilities and works in youtube, these videos will surprise you.

Original article

• Alternativas al software propietario (XII): GIMP, editor de imágenes.

Open alternatives to propietary software (XI): double panel explorers (NC clones)

Double panel explorer, similars to old Norton Commander in DOS, are very easy to use and useful to navigate in different devices and paths (HDD, DVD-ROM, etc...).

There is a lot of clones of NC and a lot of them are open source, these are my recomendations:

mc (midnight commander)

The ideal solution for browsing the GNU/Linux paths from the console, it is one of the first programs I install in any distro.

You can install it from your distro software center or from console with these commands as root:

apt-get install mc # Debian, ubuntu or similar

yum install mc # Red hat, Centos, Fedora or similar

gnome-commander

Very useful in gnome or any other graphic enviroment.

You can install it from your distro software center or from console with these commands as root:

apt-get install gnome-commander mild # Debian, ubuntu or similar

yum install gnome-commander # Red hat, Centos, Fedora or similar

All these software can do, at least, these operations with files and folders: copy, move, delete, edit, search content, change permissions and ownership and much more.

But there is a lot of open source clones I still don't prove it.

Original article

• Alternativas al software propietario (XI): los comandantes.

Open alternatives to propietary software (X): web browsers

Any open web browser is the best option to surf in the web with security, especially since the vulnerabilities are discovered very soon and corrected right away, using a private one is like playing Russian roulette.
These are some of most well-know:

• Mozilla Firefox, one of the more used web browsers in the World. It's a powerfull and secure web browser.
• Google Chrome another open source web browser, but made by google and apparently it monitors us while we use. There are a lot of people, including myseft,  that doesn't like this circustance.
  But again the advantages of free software are evident in this case, doesn't like how this web browser works? No problem, we made a fork: Chromium... but in this case Chrome is the fork than add spy code.
• Chromium this is handled the same as google chrome but without that disturbing monitoring and works with most chrome plugins, it is also very fast and secure.
• Other less known web browsers are Midori, SeaMonkey, etc

All of them are available for Windows, Mac and GNU/Linux, in the last case we do not even have to install Firefox because it usually comes standard on all distros, for something will be.

Multi-construction LDraw configuration kit: install tools to make your TENTE and LEGO models in your computer with Ubuntu

Multi-construction LDraw configuration kit installs and configured these applications to create and see 3D models of several construction systems:

• MLCad 3.40
• BMP2LDraw
• LDDesignPad
• LD4DStudio
• ldglite_1.3.1
• ldraw_2017.01
• ldview_4.3-ubuntu18.04
• leocad_17.07
• lpub_4.0
• povray 3.7
• Blender

Other resources:

• LDraw TENTE set (Jasolo)
• LDraw LEGO set (http://www.ldraw.org/)
• LDraw EXIN CASTILLOS set: COMMING SOON!
• My 3D models, customs and oficial ones.

Ubuntu Linux installation

1. Download this kit in any folder.
2. Open console and select this folder.
3. Type: sudo ./install.sh

Windows installation

For now you need to install this set manually in Windows:

1. Download LDView and install it.
2. Make the folder C:\LDRAW and uncompress this kit in this folder.
3. Uncompress these set of pieces in these folders:
   • C:\LDRAW\TENTE.
   • C:\LDRAW\EXINCASTILLOS (you need authenticate in this web).
   • C:\LDRAW\LEGO.
4. Uncompress these software in these folders:
   • MLCad 3.40 in C:\LDRAW\SOFTWARE\MLCAD_V3.40 (Optional).
   • BMP2LDRAW in C:\LDRAW\SOFTWARE\BMP2LDRAW
   • LDDesignPad in C:\LDRAW\SOFTWARE\LDDP
   • Etc...
5. Copy in Desktop the files of this folder C:\ldraw\software\accesos-directos-Windows.

Linapple y The Octalyzer: Apple II emulators for GNU/Linux

Linapple

Linapple is an emulator of the mythical Apple II quite simple and intuitive to use:

  

Instalation

Follow these steps to install it in GNU/Linux (Debian, Raspbian or Ubuntu):

• Download the source code from sourceforge.
• Uncompress it.
• Install all the necessary packages to compile it.
  sudo apt-get install zlib1g-dev libcurl3 libzip-dev libsdl1.2-dev libcurl4-gnutls-dev
• Compile it:
  cd src
make
sudo make install

Use

To run the emulator just type 'linapple' in the linux console.
Press F1 and you get information about all the function keys:

The Octalyzer

Other amazing Apple ][ emulator is The Octalyzer:

• Multisystem: available for GNU/Linux (32 & 64 bits), Windows (32 & 64 bits) and OSX.
• It's a unique binary file, you only need copy it to /usr/local/lib and run octalizer to enjoy it.
• Drag and drop disk images to the windows, to open them.
• Can render the images to 3D

Enjoy both emulators :)

Open alternative to propietary software (IX): ClamWin/ClamAV the open source antiviral software

Windows users need an antiviral software to get a minimal security, although given how vulnerable this system none of them is completely effective.
Privative antivirus usually eat a lot of resources of your computer, run for a short time because the licence expires and requires more money to update it (an non-update antivirus is useless), dirts your system, complete uninstall is very difficult, etc...

Clamwin is a different antiviral software: it can run on a pentium II without hang it, you can update the database viruses everyday and free and you can uninstall when you like as any other Windows software and it's open source.

The fact that it is a free program is a guarantee against suspicions, more judicious than paranoid, about the true intentions of most antiviruses and to what extent they protect or are part of the problem: a free antivirus does not benefit as much from the proliferation of viruses as the private ones that make their business go very well.

There is also a GNU/Linux version called Clamav.
I personally do not see any sense to have an antivirus in a system in which viruses do not pass theoretical experiments without practical danger.

You can keep safe your GNU/Linux updating the system and a bit of common sense.

How to compile and install povray in Ubuntu, Debian and distro derivates

Povray is a ray tracer available for several systems, although on unix systems you need to compile it, but it's easy following these steps:

Compile and install

Install the libraries you need to compile:

sudo apt-get install zlib1g-dev libpng12-dev libjpeg-dev libtiff5-dev libopenexr-dev libsdl1.2-dev libboost-system1.55-dev libboost1.55-dev git

Download the latest source code:

git clone https://github.com/POV-Ray/povray.git povray

Compile and install:

cd povray/unix
./prebuild.sh
cd ..
./configure COMPILED_BY="your name" LIBS="-lboost_system -lboost_thread"
make
sudo make install

Now, povray is installed in your computer.

Note: You needn't LIBS="-lboost_system -lboost_thread" in Debian.

How to use

You can generate a Full HD image with this command:

povray -W1920 -H1024 file.pov

Pov file is a text file with all the instructions in povray language to render a image (may be a very big file).

You can get amazing images like this:

Open alternatives to propietary software (VIII): Transmission, the bittorrent client

Transmission is the bittorrent client included in a lot of GNU/Linux distros.

You only need open a .torrent file and the software add the petition to the queue.

You can run Transmission and work with your computer as usual because this software doesn't cannibalize your computer resources like other bittorrent clients.

 

Are still anybody than says that GNU/Linux is not easy?

How to install your favourite GNU/Linux distro on a USB stick as if were an internal hard disk

No, we are not going to make a live pendrive, but install a Linux distro on a pendrive as if installing it on the internal disk of the computer, this will give us mobility like a live usb and versatility like a complete installation.

Preliminaries

We can do this in many ways but to make it easy and safe even for the most newbies users we will use VirtualBox.

Virtual machine setup

1. Start assistant to create a new virtual machine (New button).
2. Type: Linux.
3. Version: Ubuntu 64 bits.
4. Memory size: enought but not to much (select intro the green stripe).
   An example: my computer has 8Gb RAM, then select 3Gb.
5. Hard drive: WE DO NOT ADD ANYONE (we see why later).
6. Clic on Create.

After the virtual machine is created we ajust some parameters. We clic with right button over virtual machine and select Configuration:

1. Storage: select CD and then CD with arrow icon to select the distro iso file like virtual CD.
2. System: select Start order and move optical device as first one.
3. USB: Enable USB controller (use 2.0).
   Add usb stick where we are goint to install the distro (it must be plug to the computer).
4. Accept changes and double click on virtual machine to start instalation.

Installing OS

• Follow the assistant instructions (very easy in any Ubuntu or derivatives).
• Select delete all the drive and use all of it. So it will create all the partitions in the right way for most types of computers.
• When installing ends it ask us to remove the CD and then play any key. We do it and switch the virtual machine off when we see BIOS screen.
  At this point following operations must make in a real computer due to VirtualBox can boot usb devices.
• Close virtualbox and switch our computer off.

Use

• First configure computer BIOS to boot from USB devices (In most computers you can access to the BIOS pressing ESC or F2).
• The computer will start like it was installed in internal disc, you can update the system, add software or files, configure whan you need... all will be there when you start this again in any computer.

Advantages and disadvantages

Advantages

• This is a normal instalation and you can do all you can if you install it in the internal disc.
• If you need a driver like wifi one, you can start from another computer, install it and then start in your computer and wifi works.
• Your computer in your pocket, you can use it if there is a computer than you can boot from USB.
• You can clone it to another USB or internal disc with dd or tools like etcher.

Disadvantages

• USB stick are usually smaller than internal disc, this limit you if you want to install a lot of software or add big files.
• Remember than USB stick is a solid state device. Don't complete fill to avoid writing in the same sectors all the time.
• USB ports are less faster than internal SATA ones, I recoment use USB 3.0 devices and ports.
• Don't remove the USB until the system finish to switch off. USB stick are more delicate than internal disc in this case.
• You can install the system in an internal disc with an easy assistant, you can use tools like systemback or clone it with clonezilla, for example.

Open alternatives to privative software (VII): Libreoffice.org, the office suite

There is a lot of user that needs a computer just for use a web browser and a simple office suite.

These use can work with GNU/Linux without a great effort, and they keep reading all the files the had in office formats using LibreOffice.

This office suite is included in most GNU/Linux distros and also can read visio and pdf files and much more formats.

Available for a lot of systems (i.e: Windows and OSX) and there isn't any real reasons that avoid change to LibreOffice.org

Clone a microsd in another slightly smaller one

I clone a microsd in another slightly smaller one using gparted following these steps:

1. After get the error in the destination microsd plugged in my Linux PC, start gparted as root.
2. Unmount all the microsd partitions. We see some warning, ignore them.
3. Reduce last partition and the extended where it is.
4. After the operation is ended, run sync twice and then extract the microsd. Might be stopped warning messages.

If you haven't GNU/Linux in your PC you can use gparted-live.

Tip: if your graphic image burner tool can burn images bigger than your microsd try dd in GNU/Linux.

How to send youtube videos from your PC with Firefox quantum to KODI

You can send a youtube video from your new Firefox "quantum" to a computer with Kodi as your raspberry f.e. with the  addon 'Send to kodi'.

Install the addon

1. Visit Send to kodi website. 
2. Select 'Add to Firefox'.
3. Select 'Add' again.

Configure the addon

1. Clic on three stripes button (≡)
2. Select 'Accesories', 'Extensions' and 'Send to Kodi'.
3. Clic on 'Preferences' button.
4. Now you can see a page where you can add all the KODI computers URLs you'll use.

Use the addon

1. Search a youtube video with firefox quantum in your PC.
2. Clic on the new KODI icon. You can see it in the address bar.
3. If you configured only a video server, the video will start in KODI device immediately. If you configured more than one, you need to select where you are going to send.

Open alternatives to privative software (VI): evince, the PDF reader

Adobe reader users see this software get bigger and bigger, now is an enormous monster just for reading pdf files.

Fortunately there are a lot of alternative programs that can do this work with a few sizes and more reasonable requirements for this simple mission.

 Evince is one of them, the pdf reader included in most new GNU/Linux distros.
This software open files much faster because it is light software.

Can read all these formats:

• PDF
• Postscript
• djvu
• tiff
• dvi
• XPS
• SyncTex support with gedit
• comics books (cbz, cbr, cb7 and cbt)

Available in a lot of languages:

This an exclusive GNU/Linux software and a good reason to join to tux, anyway there is a lot of alternatives for other systems.

How configure WiFi in recalbox?

To configure WiFi in recalbox just follow these steps:

1. Start your raspberry pi recalbox with a keyboard connected to your raspberry pi.
2. Press Enter to access to menu.
3. Move cursor keys until you select Network configuration and then press A key.
4. Move cursor keys until you select SSID Wifi and then press A key.
5. Use the cursor keys to focus over text area, then press A key, write your SSID name, press Enter, move cursor keys until you select OK and then press A key.
6. Move cursor keys until you select Wifi password and  then press A key.
7. Use the cursor keys to focus over text area, then press A key, write your Wifi password, press Enter, move cursor keys until you select OK and then press A key.
8. Move cursor keys until you select Activate Wifi and change to ON use the A key.
9. Move cursor keys until you select Return and  then press A key.
10. Wait for a seconds and you'll see a dialog box than shows "Activated WiFi". You can close this dialog with A key. 

Your raspberry pi might be connected to wifi.

Problems?

If your raspberry still isn't connect, may be in one of these cases:

• Remember than SSID name and wifi password are case sensitive.
• If you use strange caracters in SSID name or wifi password then use wire connection and access to share network resource.
  Search the file system/recalbox.conf and edit wifi values.
• Use channels allowed in France or recalbox doesn't see your wifi network (example: in Spain channel 12 is allowed but not in France, this selection won't work).
  The solution is change wifi channel in your router.

Source

• Cómo configurar la red Wifi en Recalbox (vídeo youtube).

Open alternatives to propietary software (V): Audacity: audio software for multi-track recording and editing

Audicity is the best program to digitize audio in your computer, the perfect tool for this task:

• Multisystem: available for GNU/Linux, Windows and Mac.
• Light but very powerful.
• Multi-track.
• Easy to use. Intuitive.
• The size limit of your file is the free space in your hard disk, other propietary software need save temporal in memory because are too slow, when out of memory these programs hang.
• You can export to wav, ogg vorbis and mp3.
• You can add more features with  plugins and libraries like use other formats like older retrocomputers ones.

I make a manual to convert several audio files to mp3 or ogg files with audacity.

LDraw viewers and editors in Ubuntu 16.04. Your favourite construction game, now virtual in your PC

The last Ubuntu LTS version has many new features, but some exotic programs have stopped working and you have to compile them or wait for versions to run them on this version.

Just follow this guide if you want make your own Tente(R), Lego(R), Exin Castillos(R), etc... 3D models with the open format LDraw.

LDraw editors: MLCad & LeoCAD

You can install both of them without any problem, MLCad is a Windows sofware than run very well with wine, so if you want to use in any GNU/Linux install first wine and them MLCad like any other Windows application.

To install LeoCAD follow the guide I make for previous versions of Ubuntu.

LDraw viewer: LDView

You can install the new special versions for Ubuntu 16.04 , 64 bits or 32 bits.

Then you can install it with commands like this:

sudo dpkg -i ldview-4.2-ubuntu-16.04.XXX.deb
sudo apt-get install -f

Professional screenshots: povray

You can get screenshots like a 3D professional:

• Export the model to povray form LDVIEW
• You can get a Full HD screenshot with a command like this:

povray my_model.pov -W1920 -H1080

The problem is that if we install the povray package in the Ubuntu 16.04 repositories it does not work because of a problem in a library, so we have to recompile it ... ugh! how difficult! That it is enough that you copy and paste in your console the following commands:

sudo apt-get install git build-essential libvips-dev libboost-system1.58-dev libboost-thread1.58-dev libc6-dev libgcc1 libilmbase12 libjpeg8-dev libopenexr22 libpng12-dev libsdl1.2-dev libstdc++6-4.7-dev libtiff5-dev zlib1g-dev
./configure COMPILED_BY="tu nombre y correo" --disable-io-restrictions
git clone https://github.com/POV-Ray/povray
cd unix
./prebuild.sh
cd ..
make check
sudo make install

And now you get it.

Set of pieces

You need the set of the pieces of the constuction game you want to use: TENTE(R), LEGO(R) or EXIN CASTILLOS(R).

Then unzip them in differents folders, for example:

• /home/your_user/ldraw/tente
• /home/your_user/ldraw/lego
• /home/your_user/ldraw/exincastillos

Then we can run LDView with this parameter:

LDView -LDrawDir=path_to_set_of_pieces

For more details see the Tente 3D wiki.

Note: The artwork is my construction in Tente 3D of the famous building of the comic 13, Rue del Percebe, the first tentexpress quiz I won :)

Shortcuts in Debian LXDE

Desktop shortcuts are very useful to order your favorite software.

There is two ways to make shortcuts in LXDE:
 

Clone shortcuts from start menu

1. Press start menu
2. Select the category
3. Right click on item we want to clone.
4. Select option 'Add to desktop'.

Made icons from scratch

• Open the console (Start => Accessories => LXTerminal).
• Select the Desktop folder
  cd Desktop
• Create a file with a name similar to my_app.desktop with this content:
  [Desktop Entry]
Version=1.0
Encoding=UTF-8
Name=Name_of_the_app
Comment=Comments_about_the_app
Exec=exec_file
Path=path_to_exec_file
Icon=path_to_icon
Type=Application
Categories=Categories_separate_with_semicolon;

• This file must have writing rights for the owner than must be the user.sudo chmod +x my_app.desktop