doc: Introduce pipx installation (#188)

Merge libsodium, pipx installations for Debian, Fedora, macOS
Keep pip installation

README.md

@@ -22,12 +22,13 @@ Powerfull, lightweight, and multi-platform command line client written with Pyth
 
 Install with your favorite package manager. See below the [packaging status paragraph](#packaging-status).
 
-### Pip
+### Pipx
 
-If you want a more recent version [install with Pip](doc/install_pip.md):
+If you want a more recent version [install with pipx](doc/install_pipx.md):
 
 ```bash
-pip3 install silkaj --user
+sudo apt install pipx
+pipx install silkaj
 ```
 
 ### Docker images

doc/install_pip.md → doc/install_pipx.md

-# Install Silkaj with Pip
+# Install Silkaj with pipx
+
+By installing Silkaj with `pipx` or `pip` from PyPI, you get latest Silkaj version
+which might not already be available into your favorite OS.
 
 You have to use a shell on Unix system.
 
-## GNU/Linux/BSD
+## Unix
 
 ### Install libsodium
 
 ```bash
-sudo apt install libsodium23 # Debian Buster
-sudo dnf install libsodium # Fedora
+# Debian
+sudo apt install libsodium23
+
+# Fedora
+sudo dnf install libsodium
+
+# macOS
+brew install libsodium
 ```
 
-### Install dependencies before installing
+### Install `pipx`
+
+Check [`pipx` documentation](https://pypa.github.io/pipx/) for an extended installation tutorial.
 
 ```bash
-sudo apt install python3-pip python3-dev python3-wheel libssl-dev
+# Debian
+sudo apt install pipx python3-dev
+
+# Fedora
+sudo dnf install pipx python3-devel
+
+# macOS
+brew install python3 pipx
 ```
 
-On Ubuntu (14.04 and 16.04) and Debian 8, you need this package too:
+Following packages might be necessary:
 
 ```bash
-sudo apt install libffi-dev
+sudo apt install libffi-dev python3-wheel libssl-dev
 ```
 
-### Completing `PATH`
+## Install with pipx
 
-After intallation, if you get a `bash: silkaj: command not found` error, you should add `~/.local/bin` to your `PATH`:
+[pipx](https://pypa.github.io/pipx/) tool is recommended for Python executables.
+It also seperate libraries into virtual environments.
+
+### Ensure path
 
 ```bash
-echo "export PATH=$PATH:$HOME/.local/bin" >> $HOME/.bashrc
-source $HOME/.bashrc
+pipx ensurepath
 ```
 
-## macOS
+### Install
+
+```bash
+pipx install silkaj
+```
 
-To install Python, run the following command:
+### Upgrade
 
 ```bash
-brew install python3
+pipx upgrade silkaj
 ```
 
-`pip3` will automatically be installed with `python3` installation.
+### Uninstall
 
-Then, install Silkaj with:
+```bash
+pipx uninstall silkaj
+```
+
+### Check Silkaj is working
 
 ```bash
-pip3 install silkaj --user
+silkaj
+```
+
+______________________________________________________________________
+
+## Install with pip
+
+### Install `pip`
+
+```bash
+# Debian
+sudo apt install python3-pip
+
+# Fedora
+sudo dnf install python3-pip
+
+# macOS: already installed with python3
 ```
 
-## Install from PyPI
+### Completing `PATH`
 
-Assuming that Python and `pip` are installed and available. You can check with:
+After intallation, if you get a `bash: silkaj: command not found` error, you should add `~/.local/bin` to your `PATH`:
 
 ```bash
-pip3 --version
+echo "export PATH=$PATH:$HOME/.local/bin" >> $HOME/.bashrc
+source $HOME/.bashrc
 ```
 
 ### Install for current user only