( ! ) Warning: Undefined variable $argv in /var/www/project/vendor/jurosh/pdf-merge/bin/composer-setup.php on line 14
Call Stack
#	Time	Memory	Function	Location
1	0.0001	355512	{main}( )	.../composer-setup.php:0

All settings correct for using Composer The installation directory "/var/www/project/vendor/jurosh/pdf-merge/bin" is not writable