From perldoc -f kill:

Unlike in the shell, if SIGNAL is negative, it kills process groups instead of processes. (On System V, a negative PROCESS number will also kill process groups, but that's not portable.) That means you usually want to use positive not negative signals. You may also use a signal name in quotes.

So the wrong way is right on *nix.

Rule One: "Do not act incautiously when confronting a little bald wrinkly smiling man."

In reply to Re: Kill negated PIDs v negated SIGs by psini
in thread Kill negated PIDs v negated SIGs by Your Mother

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