That's a conductor, in the act of conducting. That's not a composer.
mv composer.phar /usr/bin/conductor
should fix all your problems.
This is a duplicate of https://github.com/composer/getcomposer.org/issues/36 btw. You can go spend some time reading the discussion on it :)
@stof splendid! thanks for the link
Most helpful comment
mv composer.phar /usr/bin/conductor
should fix all your problems.