dnl cd && m4 -I ~/code/ext/gitignore ~/.gitignore.m4 > ~/.gitignore .metadata bin dist tmp include(`Global/OSX.gitignore') include(`C++.gitignore') include(`Objective-C.gitignore') build *~.nib include(`Autotools.gitignore') This is my first time using M4 in anger, and apparently that dn1 is a way to make a single-line comment. I know, weird. Anyway, that comment contains the invocation you need