AutoIt

SSH Commands to a Cisco Switch

Demonstrates establishing an SSH session with a Cisco switch (or similar device) and sending commands in a device console session. Each command is sent, and its output is read up to the device's next prompt.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

Background: Network devices differ from general-purpose servers in that they expose a menu- or prompt-driven console rather than a Unix shell, so exec requests are usually unavailable and driving the interactive console is the only option. That makes prompt matching the synchronization mechanism, and it is why a PTY is appropriate here despite the general advice to avoid one. Retrieving the received text between commands is essential: a prompt left in the buffer would make the next receive return immediately with the wrong output.

Chilkat AutoIt Downloads

Download Chilkat for AutoIt

AutoIt

Local $bSuccess = False

;  This example requires the Chilkat API to have been previously unlocked.
;  See Global Unlock Sample for sample code.

;  Demonstrates establishing an SSH session with a Cisco switch (or similar device) and sending
;  commands in a device console session.
;  
;  Note: QuickShell allocates a PTY, which is what a network device console expects.  The device
;  presents an interactive prompt, and each command's output is read up to the next prompt.

$oSsh = ObjCreate("Chilkat.Ssh")

Local $iPort = 22
$bSuccess = $oSsh.Connect("172.16.16.100",$iPort)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  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 $sPassword = "mySshPassword"

$bSuccess = $oSsh.AuthenticatePw("mySshLogin",$sPassword)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  Start a shell session.
Local $iChannelNum = $oSsh.QuickShell()
If ($iChannelNum < 0) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  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.
$oSsh.ReadTimeoutMs = 15000

Local $bCaseSensitive = True

;  The switch presents a prompt ending in "#".  Reading up to it confirms the session is ready.
$bSuccess = $oSsh.ChannelReceiveUntilMatch($iChannelNum,"#","utf-8",$bCaseSensitive)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

Local $sCmdOutput = $oSsh.GetReceivedText($iChannelNum,"utf-8")
If ($oSsh.LastMethodSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite($sCmdOutput & @CRLF)

;  Send a command and read its output up to the next prompt.
$bSuccess = $oSsh.ChannelSendString($iChannelNum,"show clock" & @LF,"utf-8")
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

$bSuccess = $oSsh.ChannelReceiveUntilMatch($iChannelNum,"#","utf-8",$bCaseSensitive)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  Retrieving the text also clears the receive buffer, which matters: if the prompt were left
;  buffered, the next receive would match it immediately and return the wrong output.
$sCmdOutput = $oSsh.GetReceivedText($iChannelNum,"utf-8")
If ($oSsh.LastMethodSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite($sCmdOutput & @CRLF)

;  Additional commands follow the same send / read-to-prompt / retrieve pattern.
$bSuccess = $oSsh.ChannelSendString($iChannelNum,"show version" & @LF,"utf-8")
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

$bSuccess = $oSsh.ChannelReceiveUntilMatch($iChannelNum,"#","utf-8",$bCaseSensitive)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

$sCmdOutput = $oSsh.GetReceivedText($iChannelNum,"utf-8")
If ($oSsh.LastMethodSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite($sCmdOutput & @CRLF)

$oSsh.Disconnect