> For the complete documentation index, see [llms.txt](https://pcap.ardikars.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://pcap.ardikars.com/getting-started/write-the-packets-to-a-capture-file.md).

# Write the packets to a capture file

Note: Pcap.dumpOpen(String) will override if the "savefile" already exists; If you need to add a captured packet to the existing "savefile" you can use Pcap.dumpOpenAppend(String) instead.

Docs[: libpcap](https://www.tcpdump.org/manpages/pcap.3pcap.html), [javadoc](https://javadoc.io/doc/com.ardikars.pcap/pcap-spi/latest/pcap/spi/Dumper.html).

{% tabs %}
{% tab title="Java" %}

```
public static void main(String[] _args)
    throws ErrorException, PermissionDeniedException, PromiscuousModePermissionDeniedException,
        TimestampPrecisionNotSupportedException, RadioFrequencyModeNotSupportedException,
        NoSuchDeviceException, ActivatedException, InterfaceNotUpException,
        InterfaceNotSupportTimestampTypeException {
  var service = Service.Creator.create("PcapService");
  try (var pcap = service.live(service.interfaces(), new DefaultLiveOptions())) {
    try (var dumper = pcap.dumpOpen("savefile.pcap")) {
      try {
        pcap.loop(
            10,
            (args, header, buffer) -> {
              System.out.println("Args     : " + args);
              System.out.println("Header   : " + header);
              System.out.println("Packet   : " + buffer);
              dumper.dump(header, buffer);
            },
            "Hello pcap!");
      } catch (BreakException e) {
        System.err.println(e.getMessage());
      } catch (ErrorException e) {
        System.err.println(e.getMessage());
      }
    }
  }
}
```

{% endtab %}

{% tab title="Kotlin" %}

```
fun main() {
  val service = Service.Creator.create("PcapService")
  val pcap = service.live(service.interfaces(), DefaultLiveOptions())
  val dumper = pcap.dumpOpen("savefile.pcap")
  try {
    pcap.loop(
      10,
      { args: String, header: PacketHeader, buffer: PacketBuffer ->
        println("Args     : $args")
        println("Header   : $header")
        println("Packet   : $buffer")
        dumper.dump(header, buffer)
      },
      "Hello pcap!"
    )
  } catch (e: BreakException) {
    System.err.println(e.message)
  } catch (e: ErrorException) {
    System.err.println(e.message)
  }
  dumper.close()
  pcap.close()
}
```

{% endtab %}

{% tab title="Scala" %}

```
def main(_args: Array[String]): Unit = {
  val service = Service.Creator.create("PcapService")
  val pcap = service.live(service.interfaces(), new DefaultLiveOptions())
  val dumper = pcap.dumpOpen("savefile.pcap");
  try pcap.loop(10, (args: String, header: PacketHeader, buffer: PacketBuffer) => {
    println("Args     : ", args)
    println("Header   : ", header)
    println("Packet   : ", buffer)
    dumper.dump(header, buffer)
  }, "Hello pcap!")
  catch {
    case e: BreakException =>
      System.err.println(e.getMessage)
    case e: ErrorException =>
      System.err.println(e.getMessage)
  }
  dumper.close()
  pcap.close()
}
```

{% endtab %}
{% endtabs %}