# First, the thing you want to timeout must be inside of an eval block:

eval {

  # Second, localize the signal handling and set alarm to the desired timeout limit:
  $SIG{ALRM} = sub { die "timeout\n" };
  alarm 10;
  
  # Third, add the lines of code you specifically want to timeout:
  do_something_here_that_can_timeout();
};

# Fourth: CANCEL the alarm immediately or you may have problems later!
# This should be AFTER the eval block, not inside the eval block:
alarm 0;

# Fifth: Check for errors to see if you had a timeout or something else:
if ($@ eq "timeout\n") {
   # Do whaever you need if a timeout happened
   handle_timeout();
} else {
  # You had an actual error and not a timeout, so handle it:
  handle_error($@); # or just: die $@
}