How to execute the internal program?

Question

PHP

Good afternoon!
The following question arose: there is a system () function and, in theory, it should execute all programs. However, after a little thought, I understood why it doesn't work, let's say shutdown in this function is an internal program, and system () executes only external ones
. How to execute an internal command?

Answer 1

bash shutdown

Answer 2

At one time, while solving a similar problem, I came across the nircmd.exe program for win.
I use it like this
cmd('nircmd.exe exitwin poweroff');