Run a Command on an SSH Session Channel

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Demonstrates the Chilkat Ssh.SendReqExec method, which requests execution of a command on a session channel. The first argument is the channel number and the second is the command line. This example runs a command, reads the output until the channel closes, and prints it.

local chilkat = require("chilkat")

-- Demonstrates the Ssh.SendReqExec method, which requests execution of a command on a session
-- channel.  The 1st argument is the channel number and the 2nd is the command line.

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 execution of a command.  A true return means the server accepted the request; it
-- does not mean the command itself succeeded.
success = ssh:send_req_exec(channelNum, "ls -l /tmp")
if not success then
    print(ssh.last_error_text)
    return
end

-- IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
-- it, this call waits forever if the server never sends channel close.
ssh.read_timeout_ms = 15000

-- Read the command output until the server closes the channel.
success = ssh:channel_receive_to_close(channelNum)
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()