(PowerShell) SSH -- Running Commands that Prompt for Additional Input, such as "su"

Demonstrates how to run a shell command via SSH where the shell command prompts for additional input from the client. This example demonstrates "su".

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

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

$ssh = New-Object Chilkat.Ssh

# Hostname may be an IP address or hostname:
$hostname = "172.16.16.46"
$port = 22

$success = $ssh.Connect($hostname,$port)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# If receiving output from a command stalls for more than 5 seconds, then stop waiting.
$ssh.IdleTimeoutMs = 5000

$success = $ssh.AuthenticatePw("myLogin","myPassword")
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Open a session channel. 
$channelNum = $ssh.OpenSessionChannel()
if ($channelNum -lt 0) {
    $($ssh.LastErrorText)
    exit
}

# Request a pseudo-terminal
$termType = "dumb"
$widthInChars = 120
$heightInChars = 40
$pixWidth = 0
$pixHeight = 0
$success = $ssh.SendReqPty($channelNum,$termType,$widthInChars,$heightInChars,$pixWidth,$pixHeight)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Start a shell on the channel:
$success = $ssh.SendReqShell($channelNum)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Send the su command.
# (The SSH server I'm using for testing is a Linux Ubuntu
# system running OpenSSH.  It is important in this case to send a bare-LF
# and not a CRLF.)
$cmd = "su`n"
$success = $ssh.ChannelSendString($channelNum,$cmd,"ansi")
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Read until we get the prompt for the password:
$success = $ssh.ChannelReceiveUntilMatch($channelNum,"Password:","ansi",$true)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Display what we've received so far:
$($ssh.GetReceivedText($channelNum,"ansi"))

# Send the password. (This is the equivalent of typing at the shell prompt.)
# Again, make sure it uses a bare-LF and not a CRLF.

$password = "myPassword`n"
$success = $ssh.ChannelSendString($channelNum,$password,"ansi")
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Read the response until we get the shell prompt (assuming it's successful)
# In my case, the shell prompt is: "chilkat@vivoMini64:~$ "
$myShellPrompt = "chilkat@vivoMini64:~$"
# It will be different in your case.
$success = $ssh.ChannelReceiveUntilMatch($channelNum,$myShellPrompt,"ansi",$true)
if ($success -ne $true) {
    # Check the last-error information and the session log...
    $($ssh.LastErrorText)
    # Check to see what was received.  
    $($ssh.GetReceivedText($channelNum,"ansi"))
    exit
}

# Display what we've received so far.  This clears
# the internal receive buffer, which is important. 
# After we send the command, we'll be reading until
# the next command prompt.  If the command prompt
# is already in the internal receive buffer, we'll think we're
# already finished...
$($ssh.GetReceivedText($channelNum,"ansi"))

# Send a command.  In this case, we are sending the "ls" command:
$cmd = "ls`n"
$success = $ssh.ChannelSendString($channelNum,$cmd,"ansi")
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Read until the next command prompt:
$success = $ssh.ChannelReceiveUntilMatch($channelNum,$myShellPrompt,"ansi",$true)
if ($success -ne $true) {
    # Check the last-error information and the session log...
    $($ssh.LastErrorText)
    # Check to see what was received.  
    $($ssh.GetReceivedText($channelNum,"ansi"))
    exit
}

# Display the command output:
$($ssh.GetReceivedText($channelNum,"ansi"))

# You may continue sending additional commands.
# The technique is: send the command, read until the next command prompt,
# and then fetch/clear the internal receive buffer.

# We're done, so shut it down..

# Send an EOF.  This tells the server that no more data will 
# be sent on this channel.  The channel remains open, and
# the SSH client may still receive output on this channel.
$success = $ssh.ChannelSendEof($channelNum)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Close the channel:
$success = $ssh.ChannelSendClose($channelNum)
if ($success -ne $true) {
    $($ssh.LastErrorText)
    exit
}

# Disconnect
$ssh.Disconnect()