Dragonchild is correct about how you setup signal handlers.

Better then using the UNIX command-line kill command, is using perl's built-in kill function. For example to send the INT signal to the process ID in the $pid variable you could use:

kill INT => $pid;
# which is the same as
kill 'INT', $pid;
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Note that people often do something like:

$SIG{INT} = sub { 
 # code executed on 'INT' signal here
}; # <-- that semicolon isn't optional
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...using an anonymous subroutine instead of a named one.

Often if one just wants to handle a signal differently for a small section of code one can take advantage of local to temperarily set a signal handler up. For example:

{
  my $stop = 0;
  local $SIG{INT} = sub { $stop++ }; 
  while (!$stop) {
    # the loop continues until it's left with an explict
    # last, or until the process recieves SIGINT.
  }
}
# our old SIGINT handle is restored here, because we
# left the old block.
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(Though you can of course manually store the current signal handler, set a new one, and reset the signal handler when you are done if you want.)