The Ninja manual introduction explains some of that. http://martine.github.io/ninja/manual.html http://martine.github.io/ninja/manual.html The short answer is

The Ninja manual introduction explains some of that. http://martine.github.io/ninja/manual.html http://martine.github.io/ninja/manual.html The short answer is that Ninja is conceptually similar to Make, but it dropped slow features to speed things up.