Start a Remote Shell with QuickShell

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Demonstrates the Chilkat Ssh.QuickShell method, which starts a remote shell using the simplified sequence OpenSessionChannel → SendReqPty → SendReqShell. It takes no arguments and returns the shell channel number, or -1 on failure. The default PTY size is 80 columns by 24 rows.

Dim success As Boolean = False

'  Demonstrates the Ssh.QuickShell method, which starts a remote shell using the simplified
'  sequence OpenSessionChannel, SendReqPty, and SendReqShell.  It takes no arguments and returns
'  the shell channel number, or -1 on failure.  The default PTY size is 80 columns by 24 rows.

Dim ssh As New Chilkat.Ssh

Dim sshPort As Integer = 22
success = ssh.Connect("ssh.example.com",sshPort)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  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.
Dim password As String = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin",password)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  Start the shell.  Note that QuickShell allocates a PTY, so the remote shell runs
'  interactively: it prints a command prompt and echoes the commands that are sent to it.
Dim channelNum As Integer = ssh.QuickShell()
If (channelNum < 0) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  QuickShell returns as soon as the shell request is accepted -- it does not wait for or
'  consume the initial login text or prompt.
success = ssh.ChannelSendString(channelNum,"uname -a; echo DONE_MARKER" & vbLf,"utf-8")
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


'  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

Dim caseSensitive As Boolean = False
success = ssh.ChannelReceiveUntilMatch(channelNum,"DONE_MARKER","utf-8",caseSensitive)
If (success = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If


Dim output As String = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = False) Then
    Debug.WriteLine(ssh.LastErrorText)
    Exit Sub
End If

Debug.WriteLine(output)

ssh.Disconnect()