Included with Wireshark is a small utility called editcap, which is a command-line utility for working with capture files. Its main function is to remove packets from capture files, but it can also be used to convert capture files from one format to another, as well as to print information about capture files.
Example D.3. Help information available from editcap
$ editcap -h
Editcap 0.99.6
Edit and/or translate the format of capture files.
See http://www.wireshark.org for more information.
Usage: editcap [options] ... <infile> <outfile> [ <packet#>[-<packet#>] ... ]
A single packet or a range of packets can be selected.
Packets:
-C <choplen> chop each packet at the end by <choplen> bytes
-d remove duplicate packets
-E <error probability> set the probability (between 0.0 and 1.0 incl.)
that a particular packet byte will be randomly changed
-r keep the selected packets, default is to delete them
-s <snaplen> truncate packets to max. <snaplen> bytes of data
-t <time adjustment> adjust the timestamp of selected packets,
<time adjustment> is in relative seconds (e.g. -0.5)
-A <start time> don't output packets whose timestamp is before the
given time (format as YYYY-MM-DD hh:mm:ss)
-B <stop time> don't output packets whose timestamp is after the
given time (format as YYYY-MM-DD hh:mm:ss)
Output File(s):
-c <packets per file> split the packet output to different files,
with a maximum of <packets per file> each
-F <capture type> set the output file type, default is libpcap
an empty "-F" option will list the file types
-T <encap type> set the output file encapsulation type,
default is the same as the input file
an empty "-T" option will list the encapsulation types
Miscellaneous:
-h display this help and exit
-v verbose output
$ editcap -F
editcap: option requires an argument -- F
editcap: The available capture file types for "F":
libpcap - Wireshark/tcpdump/... - libpcap
nseclibpcap - Wireshark - nanosecond libpcap
modlibpcap - Modified tcpdump - libpcap
nokialibpcap - Nokia tcpdump - libpcap
rh6_1libpcap - Red Hat 6.1 tcpdump - libpcap
suse6_3libpcap - SuSE 6.3 tcpdump - libpcap
5views - Accellent 5Views capture
dct2000 - Catapult DCT2000 trace (.out format)
nettl - HP-UX nettl trace
netmon1 - Microsoft NetMon 1.x
netmon2 - Microsoft NetMon 2.x
ngsniffer - NA Sniffer (DOS)
ngwsniffer_1_1 - NA Sniffer (Windows) 1.1
ngwsniffer_2_0 - NA Sniffer (Windows) 2.00x
niobserverv9 - Network Instruments Observer (V9)
lanalyzer - Novell LANalyzer
snoop - Sun snoop
rf5 - Tektronix K12xx 32-bit .rf5 format
visual - Visual Networks traffic capture
$ editcap -T
editcap: option requires an argument -- T
editcap: The available encapsulation types for "T":
ether - Ethernet
tr - Token Ring
slip - SLIP
ppp - PPP
fddi - FDDI
fddi-swapped - FDDI with bit-swapped MAC addresses
rawip - Raw IP
arcnet - ARCNET
arcnet_linux - Linux ARCNET
atm-rfc1483 - RFC 1483 ATM
linux-atm-clip - Linux ATM CLIP
lapb - LAPB
atm-pdus - ATM PDUs
atm-pdus-untruncated - ATM PDUs - untruncated
null - NULL
ascend - Lucent/Ascend access equipment
isdn - ISDN
ip-over-fc - RFC 2625 IP-over-Fibre Channel
ppp-with-direction - PPP with Directional Info
ieee-802-11 - IEEE 802.11 Wireless LAN
prism - IEEE 802.11 plus Prism II monitor mode header
ieee-802-11-radio - IEEE 802.11 Wireless LAN with radio information
ieee-802-11-radiotap - IEEE 802.11 plus radiotap WLAN header
ieee-802-11-avs - IEEE 802.11 plus AVS WLAN header
linux-sll - Linux cooked-mode capture
frelay - Frame Relay
frelay-with-direction - Frame Relay with Directional Info
chdlc - Cisco HDLC
ios - Cisco IOS internal
ltalk - Localtalk
pflog-old - OpenBSD PF Firewall logs, pre-3.4
hhdlc - HiPath HDLC
docsis - Data Over Cable Service Interface Specification
cosine - CoSine L2 debug log
whdlc - Wellfleet HDLC
sdlc - SDLC
tzsp - Tazmen sniffer protocol
enc - OpenBSD enc(4) encapsulating interface
pflog - OpenBSD PF Firewall logs
chdlc-with-direction - Cisco HDLC with Directional Info
bluetooth-h4 - Bluetooth H4
mtp2 - SS7 MTP2
mtp3 - SS7 MTP3
irda - IrDA
user0 - USER 0
user1 - USER 1
user2 - USER 2
user3 - USER 3
user4 - USER 4
user5 - USER 5
user6 - USER 6
user7 - USER 7
user8 - USER 8
user9 - USER 9
user10 - USER 10
user11 - USER 11
user12 - USER 12
user13 - USER 13
user14 - USER 14
user15 - USER 15
symantec - Symantec Enterprise Firewall
ap1394 - Apple IP-over-IEEE 1394
bacnet-ms-tp - BACnet MS/TP
raw-icmp-nettl - Raw ICMP with nettl headers
raw-icmpv6-nettl - Raw ICMPv6 with nettl headers
gprs-llc - GPRS LLC
juniper-atm1 - Juniper ATM1
juniper-atm2 - Juniper ATM2
redback - Redback SmartEdge
rawip-nettl - Raw IP with nettl headers
ether-nettl - Ethernet with nettl headers
tr-nettl - Token Ring with nettl headers
fddi-nettl - FDDI with nettl headers
unknown-nettl - Unknown link-layer type with nettl headers
mtp2-with-phdr - MTP2 with pseudoheader
juniper-pppoe - Juniper PPPoE
gcom-tie1 - GCOM TIE1
gcom-serial - GCOM Serial
x25-nettl - X25 with nettl headers
k12 - K12 protocol analyzer
juniper-mlppp - Juniper MLPPP
juniper-mlfr - Juniper MLFR
juniper-ether - Juniper Ethernet
juniper-ppp - Juniper PPP
juniper-frelay - Juniper Frame-Relay
juniper-chdlc - Juniper C-HDLC
juniper-ggsn - Juniper GGSN
lapd - LAPD
dct2000 - Catapult DCT2000
ber - ASN.1 Basic Encoding Rules
Where each option has the following meaning:
This option specifies that the frames listed should be kept, not deleted. The default is to delete the listed frames.
This option provides help.
This option specifies verbose operation. The default is silent operation.
This option specifies the frame encapsulation type to use.
It is mainly for converting funny captures to something that Wireshark can deal with.
The default frame encapsulation type is the same as the input encapsulation.
This option specifies the capture file format to write the output file in.
The default is libpcap format.
Specifies that packets should be truncated to {snaplen} bytes of data.
Specifies the time adjustment to be applied to selected packets.
This parameter specifies the input file to use. It must be present.
This parameter specifies the output file to use. It must be present.
This optional parameter specifies the records to include or exclude (depending on the -r option. You can specify individual records or a range of records.