sudo rm /usr/bin/composer
php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
php -r "if (hash_file('sha384', 'composer-setup.php') === '906a84df04cea2aa72f40b5f787e49f22d4c2f19492ac310e8cba5b96ac8b64115ac402c8cd292b8a03482574915d1a8') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
php composer-setup.php
php -r "unlink('composer-setup.php');"
Ejecutar alguno de estos 2, en base a donde queramos tener el ejecutable, normalmente la opción 2 (/usr/bin/composer)
sudo mv composer.phar /usr/local/bin/composer
sudo cp /usr/local/bin/composer /usr/bin/composer