I'm using oh-my-zsh a have the following alias in .zshrc:
alias composer="php -d memory_limit=-1 $(which composer)"
I get the following output:
$ composer
Could not open input file: composer:
And for:
$ which composer
composer: aliased to php -d memory_limit=-1 composer: aliased to php -d memory_limit=-1 composer: aliased to php -d memory_limit=-1 /usr/local/bin/composer
$ zsh --version
zsh 5.2 (x86_64-apple-darwin15.4.0)
Under Linux it works as expected:
$ which composer
composer: aliased to php -d memory_limit=-1 /usr/bin/composer
$ zsh --version
zsh 5.3.1 (x86_64-unknown-linux-gnu)