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EDITCAP(1)		The Wireshark Network Analyzer		    EDITCAP(1)

NAME
       editcap - Edit and/or translate the format of capture files

SYNOPSIS
       editcap [ -A <start time> ] [ -B <stop time> ]
       [ -c <packets per file> ] [ -C <choplen> ] [ -E <error probability> ]
       [ -F <file format> ] [ -h ] [ -i <seconds per file> ] [ -r ]
       [ -s <snaplen> ] [ -S <strict time adjustment> ]
       [ -t <time adjustment> ] [ -T <encapsulation type> ] [ -v ] infile
       outfile [ packet#[-packet#] ... ]

       editcap	-d  |  -D <dup window>	|  -w <dup time window>	 [ -v ] infile
       outfile

DESCRIPTION
       Editcap is a program that reads some or all of the captured packets
       from the infile, optionally converts them in various ways and writes
       the resulting packets to the capture outfile (or outfiles).

       By default, it reads all packets from the infile and writes them to the
       outfile in pcap file format.

       An optional list of packet numbers can be specified on the command
       tail; individual packet numbers separated by whitespace and/or ranges
       of packet numbers can be specified as start-end, referring to all
       packets from start to end.  By default the selected packets with those
       numbers will not be written to the capture file.	 If the -r flag is
       specified, the whole packet selection is reversed; in that case only
       the selected packets will be written to the capture file.

       Editcap can also be used to remove duplicate packets.  Several
       different options (-d, -D and -w) are used to control the packet window
       or relative time window to be used for duplicate comparison.

       Editcap is able to detect, read and write the same capture files that
       are supported by Wireshark.  The input file doesn't need a specific
       filename extension; the file format and an optional gzip compression
       will be automatically detected.	Near the beginning of the DESCRIPTION
       section of wireshark(1) or
       <http://www.wireshark.org/docs/man-pages/wireshark.html> is a detailed
       description of the way Wireshark handles this, which is the same way
       Editcap handles this.

       Editcap can write the file in several output formats. The -F flag can
       be used to specify the format in which to write the capture file;
       editcap -F provides a list of the available output formats.

OPTIONS
       -A  <start time>
	   Saves only the packets whose timestamp is on or after start time.
	   The time is given in the following format YYYY-MM-DD HH:MM:SS

       -B  <stop time>
	   Saves only the packets whose timestamp is before stop time.	The
	   time is given in the following format YYYY-MM-DD HH:MM:SS

       -c  <packets per file>
	   Splits the packet output to different files based on uniform packet
	   counts with a maximum of <packets per file> each. Each output file
	   will be created with a suffix -nnnnn, starting with 00000. If the
	   specified number of packets is written to the output file, the next
	   output file is opened. The default is to use a single output file.

       -C  <choplen>
	   Sets the chop length to use when writing the packet data. Each
	   packet is chopped by a few <choplen> bytes of data. Positive values
	   chop at the packet beginning while negative values chop at the
	   packet end.

	   This is useful for chopping headers for decapsulation of an entire
	   capture or in the rare case that the conversion between two file
	   formats leaves some random bytes at the end of each packet.

       -d  Attempts to remove duplicate packets.  The length and MD5 hash of
	   the current packet are compared to the previous four (4) packets.
	   If a match is found, the current packet is skipped.	This option is
	   equivalent to using the option -D 5.

       -D  <dup window>
	   Attempts to remove duplicate packets.  The length and MD5 hash of
	   the current packet are compared to the previous <dup window> - 1
	   packets.  If a match is found, the current packet is skipped.

	   The use of the option -D 0 combined with the -v option is useful in
	   that each packet's Packet number, Len and MD5 Hash will be printed
	   to standard out.  This verbose output (specifically the MD5 hash
	   strings) can be useful in scripts to identify duplicate packets
	   across trace files.

	   The <dup window> is specified as an integer value between 0 and
	   1000000 (inclusive).

	   NOTE: Specifying large <dup window> values with large tracefiles
	   can result in very long processing times for editcap.

       -E  <error probability>
	   Sets the probability that bytes in the output file are randomly
	   changed.  Editcap uses that probability (between 0.0 and 1.0
	   inclusive) to apply errors to each data byte in the file.  For
	   instance, a probability of 0.02 means that each byte has a 2%
	   chance of having an error.

	   This option is meant to be used for fuzz-testing protocol
	   dissectors.

       -F  <file format>
	   Sets the file format of the output capture file.  Editcap can write
	   the file in several formats, editcap -F provides a list of the
	   available output formats. The default is the pcap format.

       -h  Prints the version and options and exits.

       -i  <seconds per file>
	   Splits the packet output to different files based on uniform time
	   intervals using a maximum interval of <seconds per file> each. Each
	   output file will be created with a suffix -nnnnn, starting with
	   00000. If packets for the specified time interval are written to
	   the output file, the next output file is opened. The default is to
	   use a single output file.

       -r  Reverse the packet selection.  Causes the packets whose packet
	   numbers are specified on the command line to be written to the
	   output capture file, instead of discarding them.

       -s  <snaplen>
	   Sets the snapshot length to use when writing the data.  If the -s
	   flag is used to specify a snapshot length, packets in the input
	   file with more captured data than the specified snapshot length
	   will have only the amount of data specified by the snapshot length
	   written to the output file.

	   This may be useful if the program that is to read the output file
	   cannot handle packets larger than a certain size (for example, the
	   versions of snoop in Solaris 2.5.1 and Solaris 2.6 appear to reject
	   Ethernet packets larger than the standard Ethernet MTU, making them
	   incapable of handling gigabit Ethernet captures if jumbo packets
	   were used).

       -S  <strict time adjustment>
	   Time adjust selected packets to insure strict chronological order.

	   The <strict time adjustment> value represents relative seconds
	   specified as [-]seconds[.fractional seconds].

	   As the capture file is processed each packet's absolute time is
	   possibly adjusted to be equal to or greater than the previous
	   packet's absolute timestamp depending on the <strict time
	   adjustment> value.

	   If <strict time adjustment> value is 0 or greater (e.g. 0.000001)
	   then only packets with a timestamp less than the previous packet
	   will adjusted.  The adjusted timestamp value will be set to be
	   equal to the timestamp value of the previous packet plus the value
	   of the <strict time adjustment> value.  A <strict time adjustment>
	   value of 0 will adjust the minimum number of timestamp values
	   necessary to insure that the resulting capture file is in strict
	   chronological order.

	   If <strict time adjustment> value is specified as a negative value,
	   then the timestamp values of all packets will be adjusted to be
	   equal to the timestamp value of the previous packet plus the
	   absolute value of the <lt>strict time adjustment<gt> value. A
	   <strict time adjustment> value of -0 will result in all packets
	   having the timestamp value of the first packet.

	   This feature is useful when the trace file has an occasional packet
	   with a negative delta time relative to the previous packet.

       -t  <time adjustment>
	   Sets the time adjustment to use on selected packets.	 If the -t
	   flag is used to specify a time adjustment, the specified adjustment
	   will be applied to all selected packets in the capture file.	 The
	   adjustment is specified as [-]seconds[.fractional seconds].	For
	   example, -t 3600 advances the timestamp on selected packets by one
	   hour while -t -0.5 reduces the timestamp on selected packets by
	   one-half second.

	   This feature is useful when synchronizing dumps collected on
	   different machines where the time difference between the two
	   machines is known or can be estimated.

       -T  <encapsulation type>
	   Sets the packet encapsulation type of the output capture file.  If
	   the -T flag is used to specify an encapsulation type, the
	   encapsulation type of the output capture file will be forced to the
	   specified type.  editcap -T provides a list of the available types.
	   The default type is the one appropriate to the encapsulation type
	   of the input capture file.

	   Note: this merely forces the encapsulation type of the output file
	   to be the specified type; the packet headers of the packets will
	   not be translated from the encapsulation type of the input capture
	   file to the specified encapsulation type (for example, it will not
	   translate an Ethernet capture to an FDDI capture if an Ethernet
	   capture is read and '-T fddi' is specified). If you need to
	   remove/add headers from/to a packet, you will need
	   od(1)/text2pcap(1).

       -v  Causes editcap to print verbose messages while it's working.

	   Use of -v with the de-duplication switches of -d, -D or -w will
	   cause all MD5 hashes to be printed whether the packet is skipped or
	   not.

       -w  <dup time window>
	   Attempts to remove duplicate packets.  The current packet's arrival
	   time is compared with up to 1000000 previous packets.  If the
	   packet's relative arrival time is less than or equal to the <dup
	   time window> of a previous packet and the packet length and MD5
	   hash of the current packet are the same then the packet to skipped.
	   The duplicate comparison test stops when the current packet's
	   relative arrival time is greater than <dup time window>.

	   The <dup time window> is specified as seconds[.fractional seconds].

	   The [.fractional seconds] component can be specified to nine (9)
	   decimal places (billionths of a second) but most typical trace
	   files have resolution to six (6) decimal places (millionths of a
	   second).

	   NOTE: Specifying large <dup time window> values with large
	   tracefiles can result in very long processing times for editcap.

	   NOTE: The -w option assumes that the packets are in chronological
	   order.  If the packets are NOT in chronological order then the -w
	   duplication removal option may not identify some duplicates.

EXAMPLES
       To see more detailed description of the options use:

	   editcap -h

       To shrink the capture file by truncating the packets at 64 bytes and
       writing it as Sun snoop file use:

	   editcap -s 64 -F snoop capture.pcap shortcapture.snoop

       To delete packet 1000 from the capture file use:

	   editcap capture.pcap sans1000.pcap 1000

       To limit a capture file to packets from number 200 to 750 (inclusive)
       use:

	   editcap -r capture.pcap small.pcap 200-750

       To get all packets from number 1-500 (inclusive) use:

	   editcap -r capture.pcap first500.pcap 1-500

       or

	   editcap capture.pcap first500.pcap 501-9999999

       To exclude packets 1, 5, 10 to 20 and 30 to 40 from the new file use:

	   editcap capture.pcap exclude.pcap 1 5 10-20 30-40

       To select just packets 1, 5, 10 to 20 and 30 to 40 for the new file
       use:

	   editcap -r capture.pcap select.pcap 1 5 10-20 30-40

       To remove duplicate packets seen within the prior four frames use:

	   editcap -d capture.pcap dedup.pcap

       To remove duplicate packets seen within the prior 100 frames use:

	   editcap -D 101 capture.pcap dedup.pcap

       To remove duplicate packets seen equal to or less than 1/10th of a
       second:

	   editcap -w 0.1 capture.pcap dedup.pcap

       To display the MD5 hash for all of the packets (and NOT generate any
       real output file):

	   editcap -v -D 0 capture.pcap /dev/null

       or on Windows systems

	   editcap -v -D 0 capture.pcap NUL

       To advance the timestamps of each packet forward by 3.0827 seconds:

	   editcap -t 3.0827 capture.pcap adjusted.pcap

       To insure all timestamps are in strict chronological order:

	   editcap -S 0 capture.pcap adjusted.pcap

       To introduce 5% random errors in a capture file use:

	   editcap -E 0.05 capture.pcap capture_error.pcap

SEE ALSO
       pcap(3), wireshark(1), tshark(1), mergecap(1), dumpcap(1), capinfos(1),
       text2pcap(1), od(1), pcap-filter(7) or tcpdump(8)

NOTES
       Editcap is part of the Wireshark distribution.  The latest version of
       Wireshark can be found at <http://www.wireshark.org>.

       HTML versions of the Wireshark project man pages are available at:
       <http://www.wireshark.org/docs/man-pages>.

AUTHORS
	 Original Author
	 -------- ------
	 Richard Sharpe		  <sharpe[AT]ns.aus.com>

	 Contributors
	 ------------
	 Guy Harris		  <guy[AT]alum.mit.edu>
	 Ulf Lamping		  <ulf.lamping[AT]web.de>

1.10.3				  2013-07-28			    EDITCAP(1)
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