#!/usr/bin/env perl

use strict; # ...it's not just for teachers anymore.

my ($tmpFile, $finalFile);

sub tidyUp {
  # Time to go!
  if ($tmpFile && (-e $tmpFile)) {
    unless (-e $finalFile) {
      rename($tmpFile, $finalFile) or die ">>> Can't move $tmpFile -> $finalFile ($!)\n";;
    } else {
      die ">>> Can't move $tmpFile -> $finalFile because $finalFile already exists!\n";
    }
  } else {
    die ">>> No temporary file to move.\n";
  }
}

# Now let's catch a few well known disruptive signals -- the troublemakers ;]
$SIG{'INT'} = $SIG{'QUIT'} = $SIG{'ABRT'} = $SIG{'TERM'} = \&tidyUp;

# Go on about your business ...
open(tmpFile, $tmpFile);