websocket.sh

Copyright (C) 2016-2025 Anton Skshidlevsky (meefik), MIT

The cross platform WebSocket implementation for UNIX shell. It works on busybox and ash for embedded systems (requires installing busybox applets).

See the developer's blog

Install busybox

First of all, you need to install the busybox binary:

wget -O /bin/busybox https://busybox.net/downloads/binaries/1.35.0-x86_64-linux-musl/busybox
chmod +x /bin/busybox

Shell as a web terminal

Run web server httpd in websocket.sh directory.

For jquery.terminal:

cd jquery.terminal
WS_SHELL="busybox sh" busybox httpd -p 8080 -f

For xterm.js:

cd xterm.js
busybox telnetd -p 5023 -l /bin/sh -f ./issue
WS_SHELL="busybox telnet 127.0.0.1 5023" busybox httpd -p 8080 -vv -f

Open the terminal in browser: http://localhost:8080/

Custom usage

Run websocket.sh:

WS_SHELL="cat" busybox nc -ll -p 5000 -e ./websocket.sh

Use from browser:

var wsPort = 5000;
var ws = new WebSocket('ws://' + location.hostname + ':' + wsPort);
ws.onmessage = function(ev) {
  var textDecoder = new TextDecoder();
  var fileReader = new FileReader();
  fileReader.addEventListener('load', function () {
    var str = textDecoder.decode(fileReader.result);
    console.log('Received data: ', str);
  });
  fileReader.readAsArrayBuffer(ev.data);
}
ws.onopen = function() {
  ws.send('hello');
}

Multiple socket connections

You can use busybox inetd for multiple connections to single port for websocket.sh:

export WS_SHELL="/path/to/script.sh"
busybox inetd -e -f /path/to/inetd.conf

The /path/to/inetd.conf may look like:

5000	stream	tcp	nowait	root	/path/to/websocket.sh