NAME

       paho_c_sub - receive (subscribe to) data from an MQTT server

SYNOPSIS

       paho_c_sub  [topic]  [-t|--topic  topic] [-c|--connection connection] [-h|--host hostname]
       [-p|--port portnumber] [-i|--clientid clientid]  [-u|--username  username]  [-P|--password
       password] [-k|--keepalive keepalive-timeout] [-V|--MQTT-version 31|311|5]
       [-q|--qos 0|1|2] [-R|--no-retained] [--delimiter delimiter] [--no-delimiter]
       [--quiet] [--verbose] [--trace min|max|error|protocol]
       [--will-topic will-topic] [--will-payload will-payload] [--will-retain] [--will-qos 0|1|2]
       [--cafile cafile] [--capath capath] [--cert certfile] [--key keyfile] [--keypass password]
       [--ciphers cipher-string] [--insecure]

DESCRIPTION

       paho_c_sub receives data from an MQTT server using the Eclipse Paho C client  asynchronous
       library  (MQTTAsync).  MQTT is a protocol, operating over TCP/IP, which allows programs to
       easily communicate with each other through a server.  Messages are published to topics and
       delivered  to  any  subscribers  to  those  topics.   The  corresponding publisher program
       paho_c_pub allows MQTT messages to be sent.

       The default mode of operation is to output  each  message  to  stdout  terminated  by  the
       delimiter.

OPTIONS

       -t
       --topic
              The MQTT topic to publish the data to.

       -c
       --connection
              The  MQTT  URI to connect to, a combination of transport prefix, host, port and for
              websockets, topic.   To  connect  using  TCP  use  the  tcp  prefix,  for  example:
              tcp://localhost:1883.   An example using SSL/TLS: ssl://localhost:1883.  An example
              for    websockets,     insecure:     ws://localhost:1883/topic,     and     secure:
              wss://localhost:80/topic.

       -h
       --host The  TCP/IP  host  name  of  the  MQTT  server to connect to. Along with the --port
              option, an older alternative to using --connection.

       -p
       --port The TCP/IP port number of the MQTT server to connect  to.  Along  with  the  --host
              option, an older alternative to using --connection.

       -q
       --qos  The MQTT QoS on which to publish the message. The alternatives are 0, 1 or 2.

       -V
       --MQTTversion
              The  version  of  the MQTT protocol to use.  Valid options are 31 (or mqttv31), 311
              (mqttv311) and 5 (or mqttv5).

       --quiet
              Do not print error messages.

       --trace
              Print library internal trace.  Valid levels are min, max, error and rotocol.

       -R
       --no-retained
              Do not print messages which have the MQTT retained flag set.

       --delimiter
              The delimiter string to append to each message when printing.  Defaults to newline.

       --no-delimiter
              Do not add a delimiter to each message when printing.

       --will-topic
              Sets the MQTT will message topic to publish to. If  the  application  ends  without
              sending an MQTT disconnect, the will message will be published to this topic.

       --will-payload
              Only used if will-topic is set. Sets the MQTT will message to be published.

       --will-qos
              Only  used  if  will-topic  is  set. Sets the MQTT QoS at which the will message is
              published. The alternatives are 0, 1 or 2.

       --will-retain
              Only used if will-topic is set. Sets the MQTT retained flag on the will message.

       --cafile
              Only used with a TLS connection. The name of a file for the OpenSSL trust store.

       --capath
              Only used with a TLS connection. The name of a directory  holding  OpenSSL  trusted
              certificates.

       --cert Only used with a TLS connection. The name of a file for the TLS keystore containing
              a client certificate to be presented.

       --key  Only used with a TLS connection. The name of a file containing the  client  private
              key.

       --keypass
              Only  used  with a TLS connection. The password for the client private key file, if
              needed.

       --ciphers
              Only used with a TLS connection. A list of  cipher  suites  that  the  client  will
              present to the server during the TLS handshake.

       --insecure
              Only  used  with  a  TLS connection. Don't check that the server certificate common
              name matches the hostname.