use Data::Dump qw( pp );
# some code here
print pp \@ip;
chomp(@ip);
print pp \@ip;

##</code><code>##

my @ip;
{  
  local $/ = "\r\n"; # because this is local, the normal behaviour is restored after this block
  open my $dat, "<", $in_file or die "Can't open file $in_file: $!";
  @ip = <$dat>;
  chomp(@ip);
  close $dat;
}