NAME

mqttui-read-one - Wait for the first message on the given topic(s) and return its payload to stdout

SYNOPSIS

mqttui read-one [-r|--ignore-retained] [--only] [-p|--pretty] [--qos] [-b|--broker] [-u|--username] [--password] [-i|--client-id] [--ca-cert] [--client-cert] [--client-private-key] [--insecure] [-h|--help] [TOPIC]

DESCRIPTION

Wait for the first message on the given topic(s) and return its payload to stdout.

Returns exactly one payload of the first received message on the given topic(s). The topic of the received message is printed to stderr. This means that you can handle stdout and stderr separately.

This can be helpful for scripting to get the current temperature reading and pipe it to somewhere else:

`echo "The temperature is $(mqttui read-one room/temp)"`

The output is the exact payload in its binary form. This might be valid ASCII / Unicode but could also be something not intended to be displayed on a terminal. For a human readable format use `--pretty` or `mqttui log`.

OPTIONS

-r, --ignore-retained

Do not return on a retained message on connection, wait for another message to arrive.

Will be removed in the future in favor of `--only=live`.

--only <ONLY>

Only return a specific kind of message, either explicitly a retained one or one that is a current one, not stored on the broker.

Keep in mind that when requesting only a retained message and there is none, this will only get noticed when the first non-retained message arrives. So this might take a while. When there is no retained message the process exits with the exit code 1.

Possible values:

-p, --pretty

Parse the payload and print it in a human readable pretty form.

This might not be useful for piping the data.

--qos <LEVEL> [default: 2]

Maximum Quality of Service (`QoS`) for subscriptions and publishing.

The lower Quality of Service level for publisher and subscriber is delivered from broker to subscriber. So subscribing with 0 will never receive a 1 or 2. Publishing with 2 will be received as 1 when subscribed with 1.

- 0: at most once (fire and forget)

- 1: at least once (acknowledged delivery with potential duplicates)

- 2: exactly once (assured delivery without duplicates)

-h, --help

Print help (see a summary with '-h')

[TOPIC] [default: #]

Topics to watch

MQTT CONNECTION

-b, --broker <URL> [default: mqtt://localhost]

URL which represents how to connect to the MQTT broker.

Examples: `mqtt://localhost` `mqtt://localhost:1883` `mqtts://localhost` `mqtts://localhost:8883` `ws://localhost/path` `ws://localhost:9001/path` `wss://localhost/path` `wss://localhost:9001/path`

-u, --username <STRING>

Username to access the mqtt broker.

Anonymous access when not supplied.

--password <STRING>

Password to access the mqtt broker.

Consider using a connection with TLS to the broker. Otherwise the password will be transported in plaintext.

Passing the password via command line is insecure as the password can be read from the history! You should pass it via environment variable.

-i, --client-id <STRING>

Specify the client id to connect with

--ca-cert <FILEPATH>

Path to a trusted CA certificate PEM file for verifying the broker.

The CA certificate has to be a X.509 v3 certificate since rustls does not support the less secure v1 certificates. See: https://github.com/rustls/rustls/issues/2364

--client-cert <FILEPATH>

Path to the TLS client certificate file.

Used together with --client-private-key to enable TLS client authentication. The file has to be a DER-encoded X.509 certificate serialized to PEM.

--client-private-key <FILEPATH>

Path to the TLS client private key file.

Used together with --client-cert to enable TLS client authentication. The file has to be a DER-encoded ASN.1 file in PKCS#8 form serialized to PEM.

--insecure

Allow insecure TLS connections