On Dec 18, 2013, at 4:46 AM, Matthias Lang <wireshark@xxxxxxxxxxxxxxxxxxxx> wrote:
> 3. Wireshark can read a Pcap from stdin, but not Pcap-NG.
>
> The following works fine:
>
>> ./wireshark -r /tmp/dumpcap.pcapng
>
> But the following gets me a "Unrecognized libpcap format" dialog box:
>
>> ./wireshark -k -i - < /tmp/dumpcap.pcapng
>
> I get the same dialog box if I do this:
>
>> cat /tmp/dumpcap.pcapng > /tmp/a_named_pipe &
>> wireshark -k -i /tmp/a_named_pipe
That's better stated as "Wireshark can capture from a pipe if handed a pcap file, but not if handed a pcap-ng file"; Wireshark can't *read* from a pipe, but it can *capture* from a pipe and write the packets to a file (the packets *have* to be in a file in Wireshark, so that it can seek and re-read arbitrary packets).
And there's currently no code in dumpcap (which is what's reading from the pipe) to handle pcap-ng files, so, no, neither Wireshark nor TShark nor dumpcap can capture from a pipe if what's being written to the pipe is a pcap-ng file.
