Defaultroutepiercing

[Jason A. Donenfeld]

 Take a look at what wg-quick does to solve this:

https://git.zx2c4.com/WireGuard/tree/src/tools/wg-quick.bash#n162

It uses policy routing, which is much nicer than overriding the default route.

If, however, you do with to do it the old 0/1, 128/1 way, here's a
script to automate that: https://א.cc/gvFOR5BO/bash But I'd recommend
doing the trick that wg-quick does.