Start a Remote Shell with QuickShell

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Demonstrates the Chilkat Ssh.QuickShell method, which starts a remote shell using the simplified sequence OpenSessionChannel → SendReqPty → SendReqShell. It takes no arguments and returns the shell channel number, or -1 on failure. The default PTY size is 80 columns by 24 rows.

local chilkat = require("chilkat")

-- Demonstrates the Ssh.QuickShell method, which starts a remote shell using the simplified
-- sequence OpenSessionChannel, SendReqPty, and SendReqShell.  It takes no arguments and returns
-- the shell channel number, or -1 on failure.  The default PTY size is 80 columns by 24 rows.

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

-- Start the shell.  Note that QuickShell allocates a PTY, so the remote shell runs
-- interactively: it prints a command prompt and echoes the commands that are sent to it.
local channelNum = ssh:quick_shell()
if channelNum < 0 then
    print(ssh.last_error_text)
    return
end

-- QuickShell returns as soon as the shell request is accepted -- it does not wait for or
-- consume the initial login text or prompt.
success = ssh:channel_send_string(channelNum, "uname -a; echo DONE_MARKER\n", "utf-8")
if not success then
    print(ssh.last_error_text)
    return
end

-- IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
-- which means no limit -- without it, this call waits forever if the received data never
-- contains a match.
ssh.read_timeout_ms = 15000

local caseSensitive = false
success = ssh:channel_receive_until_match(channelNum, "DONE_MARKER", "utf-8", caseSensitive)
if not success then
    print(ssh.last_error_text)
    return
end

local output = ssh:get_received_text(channelNum, "utf-8")
if not ssh.last_method_success then
    print(ssh.last_error_text)
    return
end

print(output)

ssh:disconnect()