What is the LD_PRELOAD trick?

Question

I came across a reference to it recently on proggit and (as of now) it is not explained.

I suspect this might be it, but I don\'t know for sure.

Answer 1

With LD_PRELOAD you can give libraries precedence.

For example you can write a library which implement malloc and free. And by loading these with LD_PRELOAD your malloc and free will be executed rather than the standard ones.