my $user = $query->param('user');
my $password = $query->param('password');
my @buffer;    # !!! Added this line.
{
  no strict;
  $filename = $query->param('foofile');
  undef $/;
  my $buffer = <$filename>;   # !!! Added "my" here.
  $buffer =~ tr/\r\n/\n/;
  @buffer= split /\n/, $buffer;
}
print $buffer[0];

##</code><code>##

my $user = $query->param('user');
my $password = $query->param('password');
my @buffer= do {
  local( $/ ); #= undef
  no strict;
  my $filename = $query->param('foofile');
  split /\r?\n/, <$filename>;
}
print $buffer[0];