Included with Wireshark is a small utility called capinfos, which is a command-line utility to print information about binary capture files.
Example D.2. Help information available from capinfos
$ capinfos -h
Capinfos 0.99.6
Prints information about capture files.
See http://www.wireshark.org for more information.
Usage: capinfos [-t] [-c] [-s] [-d] [-u] [-a] [-e] [-y]
[-i] [-z] [-h] <capfile>
where -t display the capture type of <capfile>
-c count the number of packets
-s display the size of the file
-d display the total length of all packets in the file
(in bytes)
-u display the capture duration (in seconds)
-a display the capture start time
-e display the capture end time
-y display average data rate (in bytes)
-i display average data rate (in bits)
-z display average packet size (in bytes)
-h produces this help listing.
If no data flags are given, default is to display all statistics