Provided by: libcoap3-bin_4.3.1-2_amd64 
NAME
coap-client, coap-client-gnutls, coap-client-mbedtls, coap-client-openssl, coap-client-
notls - CoAP Client based on libcoap
SYNOPSIS
coap-client [-a addr] [-b [num,]size] [-e text] [-f file] [-l loss] [-m method] [-o file]
[-p port] [-r] [-s duration] [-t type] [-v num] [-w] [-A type] [-B seconds] [-G count] [-H
hoplimit] [-K interval] [-L value] [-N] [-O num,text] [-P scheme://addr[:port]] [-T token]
[-U] [-X size] [[-h match_hint_file] [-k key] [-u user]] [[-c certfile] [-j keyfile] [-n]
[-C cafile] [-J pkcs11_pin] [-M rpk_file] [-R trust_casfile]] URI
For coap-client versions that use libcoap compiled for different (D)TLS libraries,
coap-client-notls, coap-client-gnutls, coap-client-openssl, coap-client-mbedtls or
coap-client-tinydtls may be available. Otherwise, coap-client uses the default libcoap
(D)TLS support.
DESCRIPTION
coap-client is a CoAP client to communicate with 6LoWPAN devices via the protocol CoAP
(RFC 7252) using the URI given as argument on the command line. The URI must have the
scheme coap, coap+tcp, coaps or coaps+tcp. coaps and coaps+tcp are only supported when
coap-client is built with support for secure (D)TLS communication.
If coaps or coaps+tcp is being used, provided the CoAP server supports PKI and is
configured with a certificate and private key, the coap-client does not need to have a
Pre-Shared Key (-k) or certificate (-c) configured.
The URI’s host part may be a DNS name or a literal IP address. Note that, for IPv6 address
references, angle brackets are required (c.f. EXAMPLES).
OPTIONS - GENERAL
-a addr
The local address of the interface that has to be used.
Note: Do not use this option if the interface is likely to be transient - i.e. it is a
tunnel interface that may come and go, as this is likely to cause "No such device"
errors on transmission.
-b [num,]size
The block size to be used in GET/PUT/POST requests (value must be a multiple of 16 not
larger than 1024 as libcoap uses a fixed maximum PDU size of 1400 bytes). If num is
present, the request chain will start at block num. When the server includes a Block2
option in its response to a GET request, coap-client will automatically retrieve the
subsequent block from the server until there are no more outstanding blocks for the
requested content.
-e text
Include text as payload (use percent-encoding for non-ASCII characters).
-f file
File to send with PUT/POST (use - for STDIN).
-l list
Fail to send some datagrams specified by a comma separated list of numbers or number
ranges (debugging only).
-l loss%
Randomly failed to send datagrams with the specified probability - 100% all datagrams,
0% no datagrams (debugging only).
-m method
The request method for action (get|put|post|delete), default is get. (Note that the
string passed to -m is compared case-insensitive.)
-o file
A filename to store data retrieved with GET.
-p port
The port to listen on.
-r
Use reliable protocol (TCP or TLS).
-s duration
Subscribe to / observe the resource specified by URI for the given duration in
seconds.
-t type
Content format for given resource for PUT/POST. type must be either a numeric value
reflecting a valid CoAP content format or a string describing a registered format. The
following registered content format descriptors are supported, with alternative
shortcuts given in parentheses:
text/plain (plain)
application/link-format (link, link-format)
application/xml (xml)
application/octet-stream (binary, octet-stream)
application/exi (exi)
application/json (json)
application/cbor (cbor)
-v num
The verbosity level to use (default 3, maximum is 9). Above 7, there is increased
verbosity in GnuTLS and OpenSSL logging.
-w
Append a newline to received data.
-A type
Accepted media type. type must be either a numeric value reflecting a valid CoAP
content format or a string that specifies a registered format as described for option
-t.
-B seconds
Break operation after waiting given seconds (default is 90).
-G count
Repeat the Request count times with a second delay between each one. Must have a value
between 1 and 255 inclusive. Default is 1.
-H hoplimit
Set the Hop Limit count to hoplimit for proxies. Must have a value between 1 and 255
inclusive. Default is 16.
-K interval
Send a ping after interval seconds of inactivity. If not specified (or 0), keep-alive
is disabled (default).
-L value
Sum of one or more COAP_BLOCK_* flag values for different block handling methods.
Default is 1 (COAP_BLOCK_USE_LIBCOAP).
COAP_BLOCK_USE_LIBCOAP 1
COAP_BLOCK_SINGLE_BODY 2
-N
Send NON-confirmable message. If option -N is not specified, a confirmable message
will be sent.
-O num,text
Add option num with contents of text to the request. If the text begins with 0x, then
the hex text (two [0-9a-f] per byte) is converted to binary data.
-P scheme://addr[:port]
Scheme, address and optional port to define how to connect to a CoAP proxy
(automatically adds Proxy-Uri option to request) to forward the request to. Scheme is
one of coap, coaps, coap+tcp and coaps+tcp.
-T token
Define the initial starting token for the request.
-U
Never include Uri-Host or Uri-Port options.
-X size
Maximum message size to use for TCP based connections (default is 8388864). Maximum
value of 2^32 -1.
OPTIONS - PSK
(If supported by underlying (D)TLS library)
-h match_hint_file
This is a file that contains one or more lines of received Identity Hints to match to
use different user identity and associated pre-shared key (PSK) (comma separated)
instead of the -k key and -u user options. E.g., per line
hint_to_match,use_user,with_key
A line that starts with # is treated as a comment.
Note: -k key and -u user still need to be defined for the default case in case there
is no match.
-k key
Pre-shared key for the specified user identity (-u option also required).
-u user
User identity to send for pre-shared key mode (-k option also required).
OPTIONS - PKI
(If supported by underlying (D)TLS library)
Note: If any one of certfile, keyfile or cafile is in PKCS11 URI naming format (pkcs11:
prefix), then any remaining non PKCS11 URI file definitions have to be in DER, not PEM,
format. Otherwise all of certfile, keyfile or cafile are in PEM format.
-c certfile
PEM file or PKCS11 URI for the certificate. The private key can also be in the PEM
file, or has the same PKCS11 URI. If not, the private key is defined by -j keyfile.
-j keyfile
PEM file or PKCS11 URI for the private key for the certificate in -c certfile if the
parameter is different from certfile in -c certfile.
-n
Disable remote peer certificate checking.
-C cafile
PEM file or PKCS11 URI for the CA certificate that was used to sign the server
certfile. Ideally the client certificate should be signed by the same CA so that
mutual authentication can take place. The contents of cafile are added to the trusted
store of root CAs. Using the -C or -R options will trigger the validation of the
server certificate unless overridden by the -n option.
-J pkcs11_pin
The user pin to unlock access to the PKCS11 token.
-M rpk_file
Raw Public Key (RPK) PEM file or PKCS11 URI that contains both PUBLIC KEY and PRIVATE
KEY or just EC PRIVATE KEY. (GnuTLS and TinyDTLS(PEM) support only). -C cafile or -R
trust_casfile are not required.
-R trust_casfile
PEM file containing the set of trusted root CAs that are to be used to validate the
server certificate. Alternatively, this can point to a directory containing a set of
CA PEM files. The -C cafile CA does not have to be in this list and is trusted for the
validation. Using -R trust_casfile disables common CA mutual authentication which can
only be done by using -C cafile. Using the -C or -R options will will trigger the
validation of the server certificate unless overridden by the -n option.
EXAMPLES
• Example
coap-client coap://coap.me
Query the resource / from server coap.me (using the GET method).
• Example
coap-client -m get coap://[::1]/
Query the resource / on localhost using the GET method to get back the summary defined
attributes.
• Example
coap-client -m get coap://[::1]/.well-known/core
Query on the resource .well-known/core on localhost to get back a list of the known
resources along with their attribute definitions.
• Example
echo -n "mode=on" | coap-client -m put \
coap://[2001:db8:c001:f00d:221:2eff:ff00:2704]:5683/actuators/leds?color=r -f-
Send text mode=on to resource actuators/leds?color=r on the endpoint with address
2001:db8:c001:f00d:221:2eff:ff00:2704 and port 5683. Note that the port 5683 is the
default port and isn’t actually required in this instance.
• Example
coap-client -m put coap://[fec0::3]/ck -T 3a -t binary -f to_upload
Put the contents of file to_upload with content type binary (i.e.
application/octet-stream) into resource ck on fec0::3 using a token of 3a via the PUT
method.
FILES
There are no configuration files.
EXIT STATUS
0
Success
1
Failure (syntax or usage error; configuration error; document processing failure;
unexpected error)
BUGS
Please report bugs on the mailing list for libcoap:
libcoap-developers@lists.sourceforge.net or raise an issue on GitHub at
https://github.com/obgm/libcoap/issues
AUTHORS
The libcoap project <libcoap-developers@lists.sourceforge.net>