PowerShell

Send EOF on an SSH Channel

Demonstrates the Chilkat Ssh.ChannelSendEof method, which sends an SSH EOF message on a channel. The only argument is the channel number. EOF closes only the client-to-server direction; the application may still receive stdout, stderr, exit status, EOF, and CLOSE from the server.

Background: Many remote commands read standard input until it ends — wc, sort, cat and friends. Sending EOF is the SSH equivalent of pressing Ctrl+D: it tells the remote process no more input is coming so it can finish and emit results. After sending EOF, do not send more data on that channel; a later send may return true even though nothing is delivered.

Chilkat PowerShell Downloads

Download Chilkat for PowerShell

PowerShell

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

$success = $false

#  Demonstrates the Ssh.ChannelSendEof method, which sends an SSH EOF message on a channel.  The
#  only argument is the channel number.  EOF closes only the client-to-server direction; output
#  may still be received from the server.

$ssh = New-Object Chilkat.Ssh

$sshPort = 22
$success = $ssh.Connect("ssh.example.com",$sshPort)
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 = $ssh.OpenSessionChannel()
if ($channelNum -lt 0) {
    $($ssh.LastErrorText)
    exit
}

$success = $ssh.SendReqExec($channelNum,"wc -l")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  Send input to the remote command.
$success = $ssh.ChannelSendString($channelNum,"line one`nline two`nline three`n","utf-8")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  Signal that no more input will be sent.  Do not send more data on this channel afterward.
$success = $ssh.ChannelSendEof($channelNum)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  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.ReadTimeoutMs = 15000

#  Output can still be received after EOF is sent.
$success = $ssh.ChannelReceiveToClose($channelNum)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

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

$($output)

$ssh.Disconnect()