You can install the composer by running following commands in your terminal.
sudo php -r " if (hash_file( 'SHA384' , 'composer-setup.php' ) === '544e09ee996cdf60ece3804abc52599c22b1f40f4323403c44d44fdfdd586475ca9813a858088ffbc1f233e9b180f061' ) { echo 'Installer verified' ; } else { echo 'Installer corrupt' ; unlink( 'composer-setup.php' ); } echo PHP_EOL;" sudo php composer-setup.php sudo php -r "unlink( 'composer-setup.php' );" |