ulimits: https://wiki.archlinux.org/index.php/Limits.conf#nproc

:-) DOS'ing the system is frowned upon.

The conceptually same thing will also work on bourne shell. But as in the Windows case only as a script stored in file, the original with inline function definition is self-contained oneliner.

I don't know Windows scripting, but that looks like something you'd have to put in a file and call for it to work, instead of just running that on the command line. You can do the same thing on Unix systems. Writing

  $0|$0

on a file and running it should also work as a fork bomb.

Faces I can interpret:

    :(   #sadface
    :()  #dopefish
    { :  #smiling one-toothed vampire
    { :| #blank stare with hat
    :|   #blank stare without hat
    |:   #other blank stare without hat
    |:&  #blank stare with bow
    };   #winking face with mustache
    };:  #winking four-eyed alien face with mustache

Only one of those was a smile, and you generally don't want a vampire smiling at you even if they're down a tooth! ;)