Lua

Set a TTY Mode for an SSH PTY Request

Demonstrates the Chilkat Ssh.SetTtyMode method, which adds or updates one TTY mode to be included in a later SendReqPty request. The first argument is the mode name and the second is its integer value. Call it once per mode, before requesting the PTY.

Background: TTY modes are the terminal settings a PTY is created with — the same knobs stty exposes. The classic use is SetTtyMode("ECHO", 0), which stops the terminal from echoing input; that is how a password prompt keeps typed characters off the screen. Modes accumulate on the object and are sent with the next PTY request.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the Ssh.SetTtyMode method, which adds or updates one TTY mode to be included in
-- a later SendReqPty request.  The 1st argument is the mode name and the 2nd is its integer
-- value.  Call it once per mode, before SendReqPty.

local ssh = chilkat.Ssh.new()

local sshPort = 22
local success = ssh:connect("ssh.example.com", sshPort)
if not success then
    print(ssh.last_error_text)
    return
end

-- Normally you would not hard-code the password in source.  You should instead obtain it
-- from an interactive prompt, environment variable, or a secrets vault.
local password = "mySshPassword"

success = ssh:authenticate_pw("mySshLogin", password)
if not success then
    print(ssh.last_error_text)
    return
end

-- Open a session channel.  A negative return value indicates failure.
local channelNum = ssh:open_session_channel()
if channelNum < 0 then
    print(ssh.last_error_text)
    return
end

-- Request that the allocated terminal not echo input.
success = ssh:set_tty_mode("ECHO", 0)
if not success then
    print(ssh.last_error_text)
    return
end

-- The modes set above are included in the PTY request.
success = ssh:send_req_pty(channelNum, "xterm", 80, 24, 0, 0)
if not success then
    print(ssh.last_error_text)
    return
end

success = ssh:send_req_shell(channelNum)
if not success then
    print(ssh.last_error_text)
    return
end

ssh:disconnect()