PHP Fatal error: Allowed memory size of 2147483648 bytes exhausted (tried to allocate 4096 bytes) code example

Example 1: Allowed memory size of 1610612736 bytes exhausted

export COMPOSER_MEMORY_LIMIT=-1

Example 2: Allowed memory size of 1610612736 bytes exhausted 4096

php -d memory_limit=-1 composer.phar require hwi/oauth-bundle php-http/guzzle6-adapter php-http/httplug-bundle

Example 3: PHP Fatal error: Allowed memory size of 134217728 bytes exhausted

memory_limit = 64M;