@Test
	public void testLocalEchoOn() throws IOException {
		try (UnixPty pty = openpty()) {
			pty.getChild().nullSession();

			PrintWriter writer = new PrintWriter(pty.getParent().getOutputStream());
			BufferedReader reader =
				new BufferedReader(new InputStreamReader(pty.getParent().getInputStream()));

			writer.println("Hello, World!");
			writer.flush();
			assertEquals("Hello, World!", reader.readLine());
		}
	}
Choice of 127 is based on bash setting "exit code" to 127 for "command not found"
Ghidra/Framework/Pty/src/test/java/ghidra/pty/unix/AbstractUnixPtyTest.java