Just set a signal handler that sets a flag and in the endless loop exit gracefully if it is time....

my $EXIT = 0;
$SIG{INT} = sub{ warn "Caught Zap!\n"; $EXIT = 1 };

while (1) {
  print "Looping\n";
  sleep 2;
  do{ warn "Graceful exit!\n"; exit } if $EXIT;
}
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Send this a ^C and it will exit gracefully. You can set signal handlers for other signals if desired using syntax like $SIG{INT} = $SIG{HUP} = sub{...} You can't catch a SIGKILL as the OS needs some untrappable way to kill code.