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Open your terminal using Ctrl+Alt+T
and type the following commands
composer global require "laravel/installer"
export PATH="~/.config/composer/vendor/bin:$PATH"
laravel new blog
cd blog
composer install
php artisan serve
Open a web browser and visit localhost:8000
to see the laravel welcome page
Terminate php server in terminal by pressing Ctrl+C
Thus you have successfully installed laravel globally.
export PATH="$HOME/.composer/vendor/bin:$PATH"
I have added this line to ~/.bashrc on Ubuntu 18.04.
It worked for me.