User Guide

Related command line tools
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Example D.2. Help information available from dumpcap
Dumpcap 1.5.0
Capture network packets and dump them into a libpcap file.
See http://www.wireshark.org for more information.
Usage: dumpcap [options] ...
Capture interface:
-i <interface> name or idx of interface (def: first non-loopback)
-f <capture filter> packet filter in libpcap filter syntax
-s <snaplen> packet snapshot length (def: 65535)
-p don't capture in promiscuous mode
-I capture in monitor mode, if available
-B <buffer size> size of kernel buffer (def: 1MB)
-y <link type> link layer type (def: first appropriate)
-D print list of interfaces and exit
-L print list of link-layer types of iface and exit
-d print generated BPF code for capture filter
-S print statistics for each interface once every second
-M for -D, -L, and -S, produce machine-readable output
Stop conditions:
-c <packet count> stop after n packets (def: infinite)
-a <autostop cond.> ... duration:NUM - stop after NUM seconds
filesize:NUM - stop this file after NUM KB
files:NUM - stop after NUM files
Output (files):
-w <filename> name of file to save (def: tempfile)
-g enable group read access on the output file(s)
-b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
filesize:NUM - switch to next file after NUM KB
files:NUM - ringbuffer: replace after NUM files
-n use pcapng format instead of pcap
Miscellaneous:
-q don't report packet capture counts
-v print version information and exit
-h display this help and exit
Example: dumpcap -i eth0 -a duration:60 -w output.pcap
"Capture network packets from interface eth0 until 60s passed into output.pcap"
Use Ctrl-C to stop capturing at any time.
D.5. capinfos: Print information about capture
files
Included with Wireshark is a small utility called capinfos, which is a command-line utility to print
information about binary capture files.