.\" @(#) $Header: /a/cvs/386BSD/src/contrib/tcpdump/tcpslice/tcpslice.1,v 1.1.1.1 1993/06/12 14:42:16 rgrimes Exp $ (LBL)
.\" Copyright (c) 1988-1990 The Regents of the University of California.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that: (1) source code distributions
.\" retain the above copyright notice and this paragraph in its entirety, (2)
.\" distributions including binary code include the above copyright notice and
.\" this paragraph in its entirety in the documentation or other materials
.\" provided with the distribution, and (3) all advertising materials mentioning
.\" features or use of this software display the following acknowledgement:
.\" ``This product includes software developed by the University of California,
.\" Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
.\" the University nor the names of its contributors may be used to endorse
.\" or promote products derived from this software without specific prior
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
.TH TCPSLICE 1 "14 Oct 1991"
tcpslice \- extract pieces of and/or glue together tcpdump files
is a program for extracting portions of packet-trace files generated using
It can also be used to glue together several such files, as discussed
all packets from its input file(s) whose timestamps fall
within a given range. The starting and ending times of the range
may be specified on the command line. All ranges are inclusive.
The starting time defaults
to the time of the first packet in the first input file; we call
The ending time defaults to ten years after the starting time.
to \fIstdout\fP (assuming the file does not include more than
ten years' worth of data).
There are a number of ways to specify times. The first is using
Unix timestamps of the form
(this is the format specified by \fItcpdump\fP's
specifies 38 seconds and 765,400 microseconds
after 8:51PM PDT, Sept. 25, 1990.
All examples in this manual are given
for PDT times, but when displaying times and interpreting times symbolically
uses the local timezone, regardless of the timezone in which the \fItcpdump\fP
file was generated. The daylight-savings setting used is that which is
appropriate for the local timezone at the date in question. For example,
times associated with summer months will usually include daylight-savings
effects, and those with winter months will not.
Times may also be specified relative
(when specifying a starting time)
or the starting time (when specifying an ending time)
by preceding a numeric value in seconds with a `+'.
For example, a starting time of
indicates 200 seconds after the
indicate from 200 seconds after the
through 500 seconds after the
Times may also be specified in terms of years (y), months (m), days (d),
hours (h), minutes (m), seconds (s), and microseconds(u). For example,
the Unix timestamp 654321098.7654 discussed above could also be expressed
.B 90y9m25d20h51m38s765400u.
When specifying times using this style, fields that are omitted default
as follows. If the omitted field is a unit
than that of the first specified field, then its value defaults to
the corresponding value taken from either
(if the starting time is being specified) or the starting time
(if the ending time is being specified).
If the omitted field is a unit
than that of the first specified field, then it defaults to zero.
For example, suppose that the input file has a
of the Unix timestamp mentioned above, i.e., 38 seconds and 765,400 microseconds
after 8:51PM PDT, Sept. 25, 1990. To specify 9:36PM PDT (exactly) on the
To specify a range from 9:36PM PDT through 1:54AM PDT the next day we
Relative times can also be specified when using the
format. Omitted fields then default to 0 if the unit of the field is
than that of the first specified field, and to the corresponding value
or the starting time if the omitted field's unit is
than that of the first specified field. Given a
of the Unix timestamp mentioned above,
specifies a range from 10:00PM PDT on that date through 11:10PM PDT, and
specifies a range from 38.7654 seconds after 9:51PM PDT through 38.7654
seconds after 11:01PM PDT. The first hour of the file could be extracted
format there is an ambiguity between using
for `month' or for `minute'. The ambiguity is resolved as follows: if an
field then it is interpreted as specifying months; otherwise it
If more than one input file is specified then
first copies packets lying in the given range from the first file; it
then increases the starting time of the range to lie just beyond the
timestamp of the last packet in the first file, repeats the process
with the second file, and so on. Thus files with interleaved packets
merged. For a given file, only packets that are newer than any in the
preceding files will be considered. This mechanism avoids any possibility
of a packet occurring more than once in the output.
reports the timestamps of the first and last packets in each input file
and exits. Only one of these three options may be specified.
Dump the start and end times specified by the given range and
exit. This option is useful for checking that the given range actually
specifies the times you think it does. If one of
has been specified then the times are dumped in the corresponding
format; otherwise, raw format (\fB \-R\fP) is used.
Dump the timestamps of the first and last packets in each input file
as raw timestamps (i.e., in the form \fI sssssssss.uuuuuu\fP).
except the timestamps are dumped in human-readable format, similar
to that used by \fI date(1)\fP.
except the timestamps are dumped in
Direct the output to \fIfile\fR rather than \fIstdout\fP.
Vern Paxson (vern@ee.lbl.gov), of
Lawrence Berkeley Laboratory, University of California, Berkeley, CA.
An input filename that beings with a digit or a `+' can be confused
with a start/end time. Such filenames can be specified with a
leading `./'; for example, specify the file `04Jul76.trace' as
cannot read its input from \fIstdin\fP, since it uses random-access
to rummage through its input files.
refuses to write to its output if it is a terminal
(as indicated by \fIisatty(3)\fP). This is not a bug but a feature,
to prevent it from spraying binary data to the user's terminal.
Note that this means you must either redirect \fIstdout\fP or specify an
output file via \fB\-w\fP.
will not work properly on \fItcpdump\fP files spanning more than one year;
with files containing portions of packets whose original length was
more than 65,535 bytes; nor with files containing fewer than three packets.
the error message: `couldn't find final packet in file'. These problems
are due to the interpolation scheme used by
to greatly speed up its processing when dealing with large trace files.
can efficiently extract slices from the middle of trace files of any
size, and can also work with truncated trace files (i.e., the final packet
in the file is only partially present, typically due to \fItcpdump\fP
being ungracefully killed).
projects / unix-history / blob