SSH to a Cisco Switch - Processing "More" Responses

See more SSH Examples

Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

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.

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

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

#  Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
#  whose response is paged -- each page ends with "--More--" and requires a SPACE character to
#  request the next page.

$ssh = New-Object Chilkat.Ssh

$port = 22
$success = $ssh.Connect("172.16.16.100",$port)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  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.
$password = "mySshPassword"

$success = $ssh.AuthenticatePw("mySshLogin",$password)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$channelNum = $ssh.QuickShell()
if ($channelNum -lt 0) {
    $($ssh.LastErrorText)
    exit
}

#  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.ReadTimeoutMs = 15000

$caseSensitive = $true

#  In unprivileged mode the switch prompt ends with ">".
$success = $ssh.ChannelReceiveUntilMatch($channelNum,">","utf-8",$caseSensitive)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$received = $ssh.GetReceivedText($channelNum,"utf-8")
if ($ssh.LastMethodSuccess -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$($received)

#  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
$success = $ssh.ChannelSendString($channelNum,"ena`r","utf-8")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$success = $ssh.ChannelReceiveUntilMatch($channelNum,"Password:","utf-8",$caseSensitive)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$received = $ssh.GetReceivedText($channelNum,"utf-8")
if ($ssh.LastMethodSuccess -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$($received)

#  The enable password is separate from the login password, and likewise should come from a
#  secure source rather than being hard-coded.
$enablePassword = "myEnablePassword"
$success = $ssh.ChannelSendString($channelNum,$enablePassword,"utf-8")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$success = $ssh.ChannelSendString($channelNum,"`r","utf-8")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  In privileged mode the prompt ends with "#" instead of ">".
$success = $ssh.ChannelReceiveUntilMatch($channelNum,"#","utf-8",$caseSensitive)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$received = $ssh.GetReceivedText($channelNum,"utf-8")
if ($ssh.LastMethodSuccess -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$($received)

#  Run a command whose output is delivered a page at a time.
$success = $ssh.ChannelSendString($channelNum,"show running-config`r","utf-8")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  Each read ends either at the device prompt (output complete) or at "--More--" (another page
#  is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
#  configuration text and would match too early.
$saMatch = New-Object Chilkat.StringArray
$saMatch.Append("MySwitchName#")
$saMatch.Append("--More--")

$sbReceived = New-Object Chilkat.StringBuilder
$moreComing = $true

while ($moreComing) {
    $success = $ssh.ChannelReceiveUntilMatchN($channelNum,$saMatch,"utf-8",$caseSensitive)
    if ($success -eq $false) {
        $($ssh.LastErrorText)
        exit
    }

    $sbReceived.Clear()
    $pageText = $ssh.GetReceivedText($channelNum,"utf-8")
    if ($ssh.LastMethodSuccess -eq $false) {
        $($ssh.LastErrorText)
        exit
    }

    $sbReceived.Append($pageText)
    $($pageText)

    #  If this page ended with "--More--", send a SPACE to request the next page.
    $moreComing = $sbReceived.Contains("--More--",$caseSensitive)
    if ($moreComing) {
        $success = $ssh.ChannelSendString($channelNum," ","utf-8")
        if ($success -eq $false) {
            $($ssh.LastErrorText)
            exit
        }

    }

}

$ssh.Disconnect()