Merge pull request #50 from lem-project/installation-instructions

Add `make install` instructions

content/en/installation/sdl2/linux.md

@@ -10,35 +10,44 @@ weight: -20
 ## Other GNU/Linux
 
 ### Installation from scratch
+
+Dependencies:
+
 - [sbcl](https://www.sbcl.org/)
 - [sdl2](https://www.libsdl.org/)
 - [qlot](https://github.com/fukamachi/qlot)
 - [git](https://git-scm.com/)
 
+#### Install SBCL and SDL2 libraries
 
-#### Install SBCL and ncurses library
 - Debian-like distro
+
 ```
 sudo apt install sbcl build-essential libsdl2-dev libsdl2-image-dev libsdl2-ttf-dev
 ```
 
 - Fedora-like distro
+
 ```
 sudo dnf install sbcl SDL2-devel SDL2_image-devel SDL2_ttf-devel
 sudo dnf group install c-development development-tools
 ```
 
 #### Install qlot
+
 - Automatic installer
+
 ```
 curl -L https://qlot.tech/installer | bash
 ```
-For an alternative installation, https://github.com/fukamachi/qlot#installation
 
+> **Note:** For an alternative installation, see https://github.com/fukamachi/qlot#installation
 
-#### Download and build the executable
+#### Download and install
 
-- Create the directories
+There are two ways to install Lem:
+
+**1. Local installation:**
 
 ```
 mkdir $HOME/common-lisp
@@ -47,11 +56,36 @@ git clone https://github.com/lem-project/lem.git
 cd lem && make sdl2
 ```
 
-or run `make sdl2-ncurses` to build Lem with the two interfaces in it. Then choose the interface at startup with `-i / --interface`, either "sdl2" or "ncurses".
+> **Note:** You can also run `make sdl2-ncurses` to build Lem with both the SDL2 and ncurses interfaces. You can then choose the interface at startup with `-i / --interface`, either "sdl2" or "ncurses".
 
+Then add the executable to your PATH by adding this line to your `~/.bashrc`:
 
-#### Add the executable to PATH
-- Copying the PATH to `~/.bashrc`
 ```
 export PATH="$HOME/common-lisp/lem:$PATH"
 ```
+
+**2. System-wide installation:**
+
+```
+git clone https://github.com/lem-project/lem.git
+cd lem
+```
+
+First ensure qlot is installed for the root user:
+```
+sudo bash -c "curl -L https://qlot.tech/installer | bash"
+```
+
+Then install Lem:
+```
+sudo make install
+```
+
+This will:
+
+- Build Lem with both SDL2 and ncurses interfaces
+- Install the executable system-wide 
+- Add a desktop entry file with relevant file associations
+- Configure SDL2 as the default interface
+
+You can still switch between interfaces using the `-i / --interface` option when launching Lem.