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

when LD_PRELOAD is used that file will be loaded before any other $export LD_PRELOAD=/path/lib lib to be pre loaded, even this can be used in programs too

Answer 2

Here is a detailed blog post about preloading:

https://blog.cryptomilk.org/2014/07/21/what-is-preloading/

Answer 3

You can override symbols in the stock libraries by creating a library with the same symbols and specifying the library in LD_PRELOAD.

Some people use it to specify libraries in nonstandard locations, but LD_LIBRARY_PATH is better for that purpose.