lcm-spy man page

lcm-spy — traffic inspection tool


lcm-spy [options]


lcm-spy is the Lightweight Communications and Marshalling traffic inspection utility. It is a graphical tool for viewing messages received on an LCM network, and is analagous to tools like Ethereal/Wireshark and tcpdump in that it is able to inspect all LCM messages received and provide information and statistics on the channels used.

When given appropriate LCM type definitions, lcm-spy is able to automatically detect and decode messages, and can display the individual fields of recognized messages. lcm-spy is limited to displaying statistics for unrecognized messages.

lcm-spy collects the following statistics for each channel:

Channel name
Number of messages received
Message Rate (Hz)

Bandwidth (KB/s)

On its own, this information can often be used to verify that messages are being transmitted on the expected channels, and at the expected data rates.


The following options are provided by lcm-spy

-l, --lcm-url=URL
Use the specified LCM URL
-h, --help
Shows some help text and exits

Automatic Message Decoding

If a Java class generated by lcm-gen for an LCM type definition is contained within a JAR file that is on the Java classpath, lcm-spy automatically detects the class and uses Java reflection to insert the corresponding LCM type definitions into a type database. Subsequently, lcm-spy is able to automatically recognize and decode messages received that correspond to all such types.

See Also



This manual page was written by Albert Huang.


2009-07-28 LCM Lightweight Communications and Marshalling (LCM)