my @stuff;
while (<>) {
    if (/^\s/) { $stuff[-1] .= $_; }
    else { push @stuff, $_;  }
}
print grep { /keyword/ } @stuff;

##</code><code>##

my $last_entry;
while (<>) {
    if (/^\s/) {
        $last_entry .= $_;
    } else {
        print $last_entry if $last_entry =~ /keyword/;
        $last_entry = $_;
    }
    print $last_entry if $last_entry =~ /keyword/ && eof(IN);
}