The -F option of mosquitto_sub is not available in version 1.4.15.
$ mosquitto_sub --help
mosquitto_sub is a simple mqtt client that will subscribe to a single topic and print all messages it receives.
mosquitto_sub version 1.4.15 running on libmosquitto 1.4.15.
Usage: mosquitto_sub [-c] [-h host] [-k keepalive] [-p port] [-q qos] [-R] -t topic ...
[-C msg_count] [-T filter_out]
[-A bind_address] [-S]
[-i id] [-I id_prefix]
[-d] [-N] [--quiet] [-v]
[-u username [-P password]]
[--will-topic [--will-payload payload] [--will-qos qos] [--will-retain]]
[{--cafile file | --capath dir} [--cert file] [--key file]
[--ciphers ciphers] [--insecure]]
[--psk hex-key --psk-identity identity [--ciphers ciphers]]
[--proxy socks-url]
mosquitto_sub --help
-A : bind the outgoing socket to this host/ip address. Use to control which interface
the client communicates over.
-c : disable 'clean session' (store subscription and pending messages when client disconnects).
-C : disconnect and exit after receiving the 'msg_count' messages.
-d : enable debug messages.
-h : mqtt host to connect to. Defaults to localhost.
-i : id to use for this client. Defaults to mosquitto_sub_ appended with the process id.
-I : define the client id as id_prefix appended with the process id. Useful for when the
broker is using the clientid_prefixes option.
-k : keep alive in seconds for this client. Defaults to 60.
-N : do not add an end of line character when printing the payload.
-p : network port to connect to. Defaults to 1883.
-P : provide a password (requires MQTT 3.1 broker)
-q : quality of service level to use for the subscription. Defaults to 0.
-R : do not print stale messages (those with retain set).
-S : use SRV lookups to determine which host to connect to.
-t : mqtt topic to subscribe to. May be repeated multiple times.
-T : topic string to filter out of results. May be repeated.
-u : provide a username (requires MQTT 3.1 broker)
-v : print published messages verbosely.
-V : specify the version of the MQTT protocol to use when connecting.
Can be mqttv31 or mqttv311. Defaults to mqttv31.
--help : display this message.
--quiet : don't print error messages.
--will-payload : payload for the client Will, which is sent by the broker in case of
unexpected disconnection. If not given and will-topic is set, a zero
length message will be sent.
--will-qos : QoS level for the client Will.
--will-retain : if given, make the client Will retained.
--will-topic : the topic on which to publish the client Will.
--cafile : path to a file containing trusted CA certificates to enable encrypted
certificate based communication.
--capath : path to a directory containing trusted CA certificates to enable encrypted
communication.
--cert : client certificate for authentication, if required by server.
--key : client private key for authentication, if required by server.
--ciphers : openssl compatible list of TLS ciphers to support.
--tls-version : TLS protocol version, can be one of tlsv1.2 tlsv1.1 or tlsv1.
Defaults to tlsv1.2 if available.
--insecure : do not check that the server certificate hostname matches the remote
hostname. Using this option means that you cannot be sure that the
remote host is the server you wish to connect to and so is insecure.
Do not use this option in a production environment.
--psk : pre-shared-key in hexadecimal (no leading 0x) to enable TLS-PSK mode.
--psk-identity : client identity string for TLS-PSK mode.
--proxy : SOCKS5 proxy URL of the form:
socks5h://[username[:password]@]hostname[:port]
Only "none" and "username" authentication is supported.
See http://mosquitto.org/ for more information.
The -F option of mosquitto_sub is available in version 1.6.9.
$ mosquitto_sub --help
mosquitto_sub is a simple mqtt client that will subscribe to a set of topics and print all messages it receives.
mosquitto_sub version 1.6.9 running on libmosquitto 1.6.9.
Usage: mosquitto_sub {[-h host] [-p port] [-u username] [-P password] -t topic | -L URL [-t topic]}
[-c] [-k keepalive] [-q qos]
[-C msg_count] [-E] [-R] [--retained-only] [--remove-retained] [-T filter_out] [-U topic ...]
[-F format]
[-W timeout_secs]
[-A bind_address]
[-i id] [-I id_prefix]
[-d] [-N] [--quiet] [-v]
[--will-topic [--will-payload payload] [--will-qos qos] [--will-retain]]
[{--cafile file | --capath dir} [--cert file] [--key file]
[--ciphers ciphers] [--insecure]
[--tls-alpn protocol]
[--tls-engine engine] [--keyform keyform] [--tls-engine-kpass-sha1]]
[--psk hex-key --psk-identity identity [--ciphers ciphers]]
[--proxy socks-url]
[-D command identifier value]
mosquitto_sub --help
-A : bind the outgoing socket to this host/ip address. Use to control which interface
the client communicates over.
-c : disable 'clean session' (store subscription and pending messages when client disconnects).
-C : disconnect and exit after receiving the 'msg_count' messages.
-d : enable debug messages.
-D : Define MQTT v5 properties. See the documentation for more details.
-E : Exit once all subscriptions have been acknowledged by the broker.
-F : output format.
-h : mqtt host to connect to. Defaults to localhost.
-i : id to use for this client. Defaults to mosquitto_sub_ appended with the process id.
-I : define the client id as id_prefix appended with the process id. Useful for when the
broker is using the clientid_prefixes option.
-k : keep alive in seconds for this client. Defaults to 60.
-L : specify user, password, hostname, port and topic as a URL in the form:
mqtt(s)://[username[:password]@]host[:port]/topic
-N : do not add an end of line character when printing the payload.
-p : network port to connect to. Defaults to 1883 for plain MQTT and 8883 for MQTT over TLS.
-P : provide a password
-q : quality of service level to use for the subscription. Defaults to 0.
-R : do not print stale messages (those with retain set).
-t : mqtt topic to subscribe to. May be repeated multiple times.
-T : topic string to filter out of results. May be repeated.
-u : provide a username
-U : unsubscribe from a topic. May be repeated.
-v : print published messages verbosely.
-V : specify the version of the MQTT protocol to use when connecting.
Can be mqttv5, mqttv311 or mqttv31. Defaults to mqttv311.
-W : Specifies a timeout in seconds how long to process incoming MQTT messages.
--help : display this message.
--quiet : don't print error messages.
--retained-only : only handle messages with the retained flag set, and exit when the
first non-retained message is received.
--remove-retained : send a message to the server to clear any received retained messages
Use -T to filter out messages you do not want to be cleared.
--will-payload : payload for the client Will, which is sent by the broker in case of
unexpected disconnection. If not given and will-topic is set, a zero
length message will be sent.
--will-qos : QoS level for the client Will.
--will-retain : if given, make the client Will retained.
--will-topic : the topic on which to publish the client Will.
--cafile : path to a file containing trusted CA certificates to enable encrypted
certificate based communication.
--capath : path to a directory containing trusted CA certificates to enable encrypted
communication.
--cert : client certificate for authentication, if required by server.
--key : client private key for authentication, if required by server.
--keyform : keyfile type, can be either "pem" or "engine".
--ciphers : openssl compatible list of TLS ciphers to support.
--tls-version : TLS protocol version, can be one of tlsv1.3 tlsv1.2 or tlsv1.1.
Defaults to tlsv1.2 if available.
--insecure : do not check that the server certificate hostname matches the remote
hostname. Using this option means that you cannot be sure that the
remote host is the server you wish to connect to and so is insecure.
Do not use this option in a production environment.
--tls-engine : If set, enables the use of a SSL engine device.
--tls-engine-kpass-sha1 : SHA1 of the key password to be used with the selected SSL engine.
--psk : pre-shared-key in hexadecimal (no leading 0x) to enable TLS-PSK mode.
--psk-identity : client identity string for TLS-PSK mode.
--proxy : SOCKS5 proxy URL of the form:
socks5h://[username[:password]@]hostname[:port]
Only "none" and "username" authentication is supported.
See https://mosquitto.org/ for more information.
The -F option of mosquitto_sub is not available in version 1.4.15.
The -F option of mosquitto_sub is available in version 1.6.9.