SUB(1)

NAME
sub - subscribe to MQTT topics

SYNOPSIS

sub [OPTIONS]

DESCRIPTION

sub connects to the given MQTT broker and subscribes to all topics specified. Messages received on a topic are printed to stdout, prefixed with the topic the message was received on.

All options can be passed either as command-line arguments or can be specified in a simple config file.

OPTIONS

-auto-reconnect
    automatically reconnect when connection is lost

-broker URL
    broker address (should be in the form of a URL)

-ca-root FILE
    path to a FILE containing CA certificates (optional)

-cert-file FILE
    authenticate with a certificate

-clean
    discard any pending messages from the broker (default true)

-client-id STRING
    unique identifier for this client (defaults to a semi-random string)

-connect-retry
    automatically retry initial connection to broker

-connect-retry-interval DURATION
    wait DURATION between initial connection attempts (default 30s)

-config FILE
    path to FILE containing configuration values (optional)

-header KEY=VALUE
    set an HTTP header (in KEY=VALUE form) (can be specified multiple times)

-key-file FILE
    authenticate with a private key

-password STRING
    authenticate with a password

-qos INTEGER
    quality of service for messages

-tls-alpn STRING
    ALPN value to include in the TLS handshake (can be specified multiple times)

-topic STRING
    topic to publish or subscribe to (can be specified multiple times)

-username STRING
    authenticate with a username

-verbose
    increase output

-version
    print version

CONFIGURATION

Any option may be specified as a value in a configuration file instead of (or in addition to) a command-line option. Values present on the command-line take precedent over values in the configration file. Thus it is easy to create a base configration file that can be augmented easily at run time.

The configuration file takes the form of a simple space-separated "option value" format (i.e. "broker tcp://test.mosquitto.org:1883").

EXAMPLES

Connect to a broker anonymously and subscribe to two topics.

    sub -broker tcp://test.mosquitto.org:1883 -topic mqttcli/pubtest -topic mqttcli/pubtest1

Connect to a broker using username/password authentication and subscribe to a topic.

    sub -broker tcp://test.mosquitto.org:1884 -username ro -password readonly -topic mqttcli/pubtest

AUTHOR

Link Dupont <link@sub-pop.net>
    Author.