How to send USR2 signal?

Question

I read that to upgrade nginx involves among other things sending the USR2 signal with kill -USR2 pid. So I tried sudo kill -USR2 3049 but got

$ sudo kill –USR2 3049
kill: failed to parse argument: '–USR2'

Solution 1

I was copy pasting from a website and that caused the wrong dash to be used.

sudo kill –USR2 3049
sudo kill -USR2 3049

Solution 2

First invoke kill -l to list all signals

in some destro USR2 is SIGUSR2. also you can run it by it's number