Lua

Open an SSH Session Channel

Demonstrates the Chilkat Ssh.OpenSessionChannel method, which opens a new SSH session channel. It takes no arguments and returns the channel number, or -1 on failure. The transport must already be connected and authenticated.

Background: SSH multiplexes independent channels over one authenticated connection, and a session channel is the one used to run a command, start a shell, or invoke a subsystem. Opening the channel is only the container — nothing runs until you follow it with an exec, shell, or subsystem request. Always test for a negative return rather than assuming success.

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Lua

local chilkat = require("chilkat")

-- Demonstrates the Ssh.OpenSessionChannel method, which opens a new SSH session channel.  It
-- takes no arguments and returns the channel number, or -1 on failure.  The transport must
-- already be connected and authenticated.

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

print("Opened session channel: " .. channelNum)

-- Opening the channel does not start a shell or command -- send an exec, shell, or subsystem
-- request next.

ssh:disconnect()