$ websocat ws://echo.websocket.org
123
123
ABC
ABC

A$ websocat -s 1234
Listening on ws://127.0.0.1:1234/
ABC
123

B$ websocat ws://127.0.0.1:1234/
ABC
123

$ chromium --remote-debugging-port=9222&
$ curl -sg http://127.0.0.1:9222/json/new | grep webSocketDebuggerUrl | cut -d'"' -f4 | head -1
ws://127.0.0.1:9222/devtools/page/A331E56CCB8615EB4FCB720425A82259
$ echo 'Page.navigate {"url":"https://example.com"}' | websocat -n1 --jsonrpc ws://127.0.0.1:9222/devtools/page/A331E56CCB8615EB4FCB720425A82259
{"id":2,"result":{"frameId":"A331E56CCB8615EB4FCB720425A82259","loaderId":"EF5AAD19F2F8BB27FAF55F94FFB27DF9"}}

$ websocat --oneshot -b ws-l:127.0.0.1:1234 tcp:127.0.0.1:22&
$ websocat --oneshot -b tcp-l:127.0.0.1:1236 ws://127.0.0.1:1234/&
$ nc 127.0.0.1 1236
SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u3
qwertyu
Protocol mismatch.

A$ websocat -t ws-l:127.0.0.1:1234 broadcast:mirror:
B$ websocat ws://127.0.0.1:1234
C$ websocat ws://127.0.0.1:1234

websocat 1.1.0
Vitaly "_Vi" Shukela <[email protected]>
Command-line client for web sockets, like netcat/curl/socat for ws://.

USAGE:
    websocat ws://URL | wss://URL               (simple client)
    websocat -s port                            (simple server)
    websocat [FLAGS] [OPTIONS] <addr1> <addr2>  (advanced mode)

FLAGS:
    (some flags are hidden, see --help=long)
    -e, --set-environment                       Set WEBSOCAT_* environment variables when doing exec:/cmd:/sh-c:
                                                Currently it's WEBSOCAT_URI and WEBSOCAT_CLIENT for
                                                request URI and client address (if TCP)
                                                Beware of ShellShock or similar security problems.
    -E, --exit-on-eof                           Close a data transfer direction if the other one reached EOF
        --jsonrpc                               Format messages you type as JSON RPC 2.0 method calls. First word
                                                becomes method name, the rest becomes parameters, possibly automatically
                                                wrapped in [].
    -0, --null-terminated                       Use \0 instead of \n for linemode
    -1, --one-message                           Send and/or receive only one message. Use with --no-close and/or -u/-U.
        --oneshot                               Serve only once. Not to be confused with -1 (--one-message)
    -q                                          Suppress all diagnostic messages, except of startup errors
    -s, --server-mode                           Simple server mode: specify TCP port or addr:port as single argument
    -S, --strict                                strict line/message mode: drop too long messages instead of splitting
                                                them, drop incomplete lines.
    -u, --unidirectional                        Inhibit copying data in one direction
    -U, --unidirectional-reverse                Inhibit copying data in the other direction (or maybe in both directions
                                                if combined with -u)
    -v                                          Increase verbosity level to info or further
    -b, --binary                                Send message to WebSockets as binary messages
    -n, --no-close                              Don't send Close message to websocket on EOF
    -t, --text                                  Send message to WebSockets as text messages

OPTIONS:
    (some options are hidden, see --help=long)

    -B, --buffer-size <buffer_size>                Maximum message size, in bytes [default: 65536]
    -H, --header <custom_headers>...
            Add custom HTTP header to websocket client request. Separate header name and value with a colon and
            optionally a single space. Can be used multiple times.
    -h, --help <help>
            See the help.
            --help=short is the list of easy options and address types
            --help=long lists all options and types (see [A] markers)
            --help=doc also shows longer description and examples.
        --origin <origin>                          Add Origin HTTP header to websocket client request
        --restrict-uri <restrict_uri>
            When serving a websocket, only accept the given URI, like `/ws`
            This liberates other URIs for things like serving static files or proxying.
    -F, --static-file <serve_static_files>...
            Serve a named static file for non-websocket connections.
            Argument syntax: <URI>:<Content-Type>:<file-path>
            Argument example: /index.html:text/html:index.html
            Directories are not and will not be supported for security reasons.
            Can be specified multiple times.
        --protocol <websocket_protocol>            Specify Sec-WebSocket-Protocol: header
        --websocket-version <websocket_version>    Override the Sec-WebSocket-Version value
        --ws-c-uri <ws_c_uri>                      [A] URI to use for ws-c: overlay [default: ws://0.0.0.0/]

ARGS:
    <addr1>    In simple mode, WebSocket URL to connect. In advanced mode first address (there are many kinds of
               addresses) to use. See --help=types for info about address types. If this is an address for
               listening, it will try serving multiple connections.
    <addr2>    In advanced mode, second address to connect. If this is an address for listening, it will accept only
               one connection.


Basic examples:
  Command-line websocket client:
    websocat ws://echo.websocket.org/
    
  WebSocket server
    websocat -s 8080
    
  WebSocket-to-TCP proxy:
    websocat --binary ws-l:127.0.0.1:8080 tcp:127.0.0.1:5678
    

Partial list of address types:
	ws://           	Insecure (ws://) WebSocket client. Argument is host and URL.
	wss://          	Secure (wss://) WebSocket client. Argument is host and URL.
	ws-listen:      	WebSocket server. Argument is host and port to listen.
	stdio:          	Same as `-`. Read input from console, print to console.
	tcp:            	Connect to specified TCP host and port. Argument is a socket address.
	tcp-listen:     	Listen TCP port on specified address.
	sh-c:           	Start specified command line using `sh -c` (even on Windows)
	cmd:            	Start specified command line using `sh -c` or `cmd /C` (depending on platform)
	readfile:       	Synchronously read a file. Argument is a file path.
	writefile:      	Synchronously truncate and write a file.
	appendfile:     	Synchronously append a file.
	udp:            	Send and receive packets to specified UDP socket, from random UDP port  
	udp-listen:     	Bind an UDP socket to specified host:port, receive packet
	mirror:         	Simply copy output to input. No arguments needed.
	literalreply:   	Reply with a specified string for each input packet.
	literal:        	Output a string, discard input.
Partial list of overlays:
	broadcast:      	Reuse this connection for serving multiple clients, sending replies to all clients.
	autoreconnect:  	Re-establish underlying connection on any error or EOF

SSL_CERT_FILE=cacert.pem /data/local/tmp/websocat wss://echo.websocket.org