Get the Exit Status of a Remote SSH Command

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Demonstrates the Chilkat Ssh.GetChannelExitStatus method, which returns the remote process exit status for a channel. The only argument is the channel number. Call it only after ChannelReceivedExitStatus returns true.

local chilkat = require("chilkat")

-- Demonstrates the Ssh.GetChannelExitStatus method, which returns the remote process exit
-- status for a channel.  The only argument is the channel number.  Call it only after
-- ChannelReceivedExitStatus returns true.

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

local channelNum = ssh:open_session_channel()
if channelNum < 0 then
    print(ssh.last_error_text)
    return
end

success = ssh:send_req_exec(channelNum, "grep -q root /etc/passwd")
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

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

-- Retrieve the exit status immediately, before calling unrelated SSH methods or releasing the
-- channel, because the completed channel record can be discarded.
if ssh:channel_received_exit_status(channelNum) then
    local exitStatus = ssh:get_channel_exit_status(channelNum)
    print("Exit status: " .. exitStatus)

    -- By convention, 0 means the remote command succeeded.
    if exitStatus == 0 then
        print("The remote command succeeded.")
    else
        print("The remote command reported a failure.")
    end
end

ssh:disconnect()