Wireshark-users: Re: [Wireshark-users] newbie question, tshark input from stdin
From: Evan Huus <eapache@xxxxxxxxx>
Date: Mon, 3 Feb 2014 16:44:24 -0500
Hi Pete,

The -i flag is for specifying a network interface for live capture (eg
eth0) and so doesn't accept "-" to signify stdin. I'm actually a bit
surprised you're getting any data at all with that command. I would
expect the following to give more useful results:
$ cat pcapfile | tshark -r -
though tshark's ability to read from a pipe has been rather
inconsistent up until recently due to the way filetypes are detected.

(Tangential note: tshark 1.4.x is quite old and no longer officially
supported. Upgrading is a good idea, if you are able.)

Evan

On Mon, Feb 3, 2014 at 4:16 PM, Lancashire, Pete
<Pete.Lancashire@xxxxxxxxxxxxxxxxxx> wrote:
> A bit confused with  tshark -i -
>
> I have a pcap file with 1,177,880 records
>
> $ capinfos pcapfile
> File name:           pcapfile
> File type:           Wireshark/tcpdump/... - libpcap
> File encapsulation:  Ethernet
> Packet size limit:   file hdr: 65535 bytes
> Number of packets:   1177880
> File size:           772514406 bytes
> Data size:           753668302 bytes
> Capture duration:    4800 seconds
> Start time:          Fri Jan 31 13:50:00 2014
> End time:            Fri Jan 31 15:10:00 2014
> Data byte rate:      156999.79 bytes/sec
> Data bit rate:       1255998.34 bits/sec
> Average packet size: 639.85 bytes
> Average packet rate: 245.37 packets/sec
> SHA1:                1ad68104a5ea50c2392340a9e5b6f2767e6dd34f
> RIPEMD160:           519962c5e8cf8f742ebceb4d06380741fcca537b
> MD5:                 9594d754ae507f5cbe7cb6ac43cd361a
> Strict time order:   False
>
> tshark is
>
> $ tshark -v
> TShark 1.4.10
>
> Copyright 1998-2011 Gerald Combs <gerald@xxxxxxxxxxxxx> and contributors.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> Compiled (64-bit) with GLib 2.26.0, with libpcap 1.1.1, without libz, without
> POSIX capabilities, without libpcre, with SMI 0.4.8, without c-ares, without
> ADNS, with Lua 5.1, without Python, with GnuTLS 2.8.6, with Gcrypt 1.4.5, with
> MIT Kerberos, with GeoIP.
>
> Running on Linux 2.6.35.14-106.fc14.x86_64, with libpcap version 1.1.1.
>
> Built using gcc 4.5.1 20100924 (Red Hat 4.5.1-4).
>
> doing
> $ tshark -r pcapfile  2>/dev/null | wc -l
> 1177880
>
> Is what I expected
>
> but
> cat pcapfile | tshark -i -
>
> 6.027531 192.168.240.107 -> 192.168.2....
> 499 packets captured
>
> and confirming
>
> cat pcapfile | tshark -i -  2>/dev/null | wc -l
> 499
>
> What am I doing wrong ?
>
> Thanks
>
> -pete
>
>
>
>
> stops after 499 packets
>
> tshark -r pcapfile | wc -l
>
>
>
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