Specify a criterion that specifies when Wireshark is to stop writing to a capture file. The criterion is of the form test:value, where test is one of:

If a maximum capture file size was specified, this option causes Wireshark to run in "ring buffer" mode, with the specified number of files. In "ring buffer" mode, Wireshark will write to several capture files. Their name is based on the number of the file and on the creation date and time.

When the first capture file fills up, Wireshark will switch to writing to the next file, until it fills up the last file, at which point it'll discard the data in the first file (unless 0 is specified, in which case, the number of files is unlimited) and start writing to that file and so on.

If the optional duration is specified, Wireshark will also switch to the next file when the specified number of seconds has elapsed even if the current file is not completely fills up.

Win32 only: set capture buffer size (in MB, default is 1MB). This is used by the the capture driver to buffer packet data until that data can be written to disk. If you encounter packet drops while capturing, try to increase this size.

This option specifies the maximum number of packets to capture when capturing live data. It would be used in conjunction with the -k option.

Print a list of the interfaces on which Wireshark can capture, and exit. For each network interface, a number and an interface name, possibly followed by a text description of the interface, is printed. The interface name or the number can be supplied to the -i flag to specify an interface on which to capture.

This can be useful on systems that don't have a command to list them (e.g., Windows systems, or UNIX systems lacking ifconfig -a ); the number can be useful on Windows 2000 and later systems, where the interface name is a somewhat complex string.

Note that "can capture" means that Wireshark was able to open that device to do a live capture; if, on your system, a program doing a network capture must be run from an account with special privileges (for example, as root), then, if Wireshark is run with the -D flag and is not run from such an account, it will not list any interfaces.

This option sets the initial capture filter expression to be used when capturing packets.

After reading in a capture file using the -r flag, go to the given packet number.

The -h option requests Wireshark to print its version and usage instructions (as shown above) and exit.

Set the name of the network interface or pipe to use for live packet capture.

Network interface names should match one of the names listed in wireshark -D (described above); a number, as reported by wireshark -D , can also be used. If you're using UNIX, netstat -i or ifconfig -a might also work to list interface names, although not all versions of UNIX support the -a flag to ifconfig .

If no interface is specified, Wireshark searches the list of interfaces, choosing the first non-loopback interface if there are any non-loopback interfaces, and choosing the first loopback interface if there are no non-loopback interfaces; if there are no interfaces, Wireshark reports an error and doesn't start the capture.

Pipe names should be either the name of a FIFO (named pipe) or ``-'' to read data from the standard input. Data read from pipes must be in standard libpcap format.

The -k option specifies that Wireshark should start capturing packets immediately. This option requires the use of the -i parameter to specify the interface that packet capture will occur from.

This option turns on automatic scrolling if the packet list pane is being updated automatically as packets arrive during a capture ( as specified by the -S flag).

List the data link types supported by the interface and exit.

This option sets the name of the font used for most text displayed by Wireshark. XXX - add an example!

Disable network object name resolution (such as hostname, TCP and UDP port names).

Turns on name resolving for particular types of addresses and port numbers; the argument is a string that may contain the letters m to enable MAC address resolution, n to enable network address resolution, and t to enable transport-layer port number resolution. This overrides -n if both -N and -n are present. The letter C enables concurrent (asynchronous) DNS lookups.

Sets a preference or recent value, overriding the default value and any value read from a preference/recent file. The argument to the flag is a string of the form prefname:value, where prefname is the name of the preference (which is the same name that would appear in the preference/recent file), and value is the value to which it should be set. Multiple instances of -o <preference settings> can be given on a single command line.

An example of setting a single preference would be:

wireshark -o mgcp.display_dissect_tree:TRUE

An example of setting multiple preferences would be:

wireshark -o mgcp.display_dissect_tree:TRUE -o mgcp.udp.callagent_port:2627

	Tip!
	You can get a list of all available preference strings from the preferences file, see Appendix A, Files and Folders .

User access tables can be overridden using "uat," followed by the UAT file name and a valid record for the file:

wireshark -o "uat:user_dlts:\"User 0 (DLT=147)\",\"http\",\"0\",\"\",\"0\",\"\""

The example above would dissect packets with a libpcap data link type 147 as HTTP, just as if you had configured it in the DLT_USER protocol preferences.

Don't put the interface into promiscuous mode. Note that the interface might be in promiscuous mode for some other reason; hence, -p cannot be used to ensure that the only traffic that is captured is traffic sent to or from the machine on which Wireshark is running, broadcast traffic, and multicast traffic to addresses received by that machine.

Special path settings usually detected automatically. This is used for special cases, e.g. starting Wireshark from a known location on an USB stick.

The criterion is of the form key:path, where key is one of:

This option forces Wireshark to exit when capturing is complete. It can be used with the -c option. It must be used in conjunction with the -i and -w options.

This option provides the name of a capture file for Wireshark to read and display. This capture file can be in one of the formats Wireshark understands.

This option specifies a display filter to be applied when reading packets from a capture file. The syntax of this filter is that of the display filters discussed in Section 6.3, “Filtering packets while viewing”. Packets not matching the filter are discarded.

This option specifies the snapshot length to use when capturing packets. Wireshark will only capture <snaplen> bytes of data for each packet.

This option specifies that Wireshark will display packets as it captures them. This is done by capturing in one process and displaying them in a separate process. This is the same as "Update list of packets in real time" in the Capture Options dialog box.

This option sets the format of packet timestamps that are displayed in the packet list window. The format can be one of:

The -v option requests Wireshark to print out its version information and exit.

This option sets the name of the savefile to be used when saving a capture file.

If a capture is started from the command line with -k, set the data link type to use while capturing packets. The values reported by -L are the values that can be used.

Specify an option to be passed to a TShark module. The eXtension option is in the form extension_key:value, where extension_key can be:

lua_script :lua_script_filename; Tells Wireshark to load the given script in addition to the default Lua scripts.

Get Wireshark to collect various types of statistics and display the result in a window that updates in semi-real time. XXX - add more details here!