Composer is a dependency manager for PHP, that lets you manage dependencies by offering install/uninstall and options like creating projects.
It's easy to install it on Mac, all you have to do is run this curl command in your Terminal.
curl -sS https://getcomposer.org/installer | php
You will now have a
composer.phar, which is executable.
You can move the file to the
/usr/loca/bin directory to make it accessible from anywhere.
sudo cp composer.phar /usr/local/bin/composer
Now when you run composer from your terminal you should get a greeting screen from Composer.