#!/usr/bin/perl -w

print "Hello World!\n";

BEGIN
{
    local $/;
    open (ME,$0);
    my $me = <ME>;
    close ME;
    unless ($me =~ m/#avshc='\d+'$/) {
        my $length = length $me;
        open (ME, ">>$0");
        print ME "#avshc='$length'";
        close ME;
        $me .= "#avshc='$length'";
    }
    $me =~ s/#avshc='(\d+)'$//;
    die "File $0 has changed ?viral infection?\n" unless $1 == length $me;
}