1. CLI

The Fast DDS command line interface provides a set commands and sub-commands to perform, Fast DDS related, maintenance and configuration tasks.

An executable file for Linux and Windows that runs the Fast DDS CLI application is available in the tools folder. If the tools/fastdds folder path is added to the PATH, or by sourcing the <path/to/fastdds>/install/setup.bash configuration file, Fast DDS CLI can be executed running the following commands:

  • Linux:

    $ fastdds <command> [<command-args>]
  • Windows:

    > fastdds.bat <command> [<command-args>]

There are two verbs whose functionality is described in the following table:




Launches a server for Discovery Server.


Allows manual cleaning of garbage files that may be generated by Shared Memory Transport

1.1. discovery

Launches a server for Discovery Server. This server will manage the messages of the clients which are pointed to its IP address. Clients must be aware of how to reach the server by specifying an IP address and a transport protocol like UDP or TCP. Servers do not need any knowledge of their clients beforehand, but require the listening IP address, where they may be reached. For more information on how to configure the discovery mechanism in Fast DDS, please refer to Discovery.

fastdds discovery -i {0-255} [optional parameters]

Where the parameters are:



-i  --server-id

Mandatory unique server identifier. Specifies zero based server position in
ROS_DISCOVERY_SERVER environment variable.

-h  -help

Produce help message.

-l  --ip-address

IP address chosen to listen the clients. Defaults to any (

-p  --port

UDP port chosen to listen the clients. Defaults to ‘11811’.

-b  --backup

Creates a server with a backup file associated.

1.1.1. Examples

  1. Launch a default server with id 0 (first on ROS_DISCOVERY_SERVER) listening on all available interfaces on UDP port ‘11811’. Only one server can use default values per machine.

    fastdds discovery -i 0
  2. Launch a default server with id 1 (second on ROS_DISCOVERY_SERVER) listening on localhost with UDP port 14520. Only localhost clients can reach the server defining as ROS_DISCOVERY_SERVER=; .

    fastdds discovery -i 1 -l -p 14520
  3. Launch a default server with id 2 (third on ROS_DISCOVERY_SERVER) listening on WiFi ( and Ethernet ( local interfaces with UDP ports 8783 and 51083 respectively (addresses and ports are made up for the example).

    fastdds discovery -i 2 -l -p 8783 -l -p 51083
  4. Launch a default server with id 3 (fourth on ROS_DISCOVERY_SERVER) listening on with UDP port 12345 and provided with a backup file. If the server crashes it will automatically restore its previous state when re-enacted.

    fastdds discovery -i 3 -l -p 12345 -b

1.2. shm

Provides maintenance tasks related with Shared Memory Transport. Shared Memory transport creates Segments, blocks of memory accessible from different processes. Zombie files are memory blocks that were reserved by shared memory and are no longer in use which take up valuable memory resources. This tool finds and frees those memory allocations.

fastdds shm [<shm-command>]




Cleans SHM zombie files.



-h  -help

Produce help message.