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Start a Remote Shell with QuickShell

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.

Background: Note that QuickShell does allocate a PTY, so unlike a bare SendReqShell the remote shell runs interactively: it prints a command prompt, echoes the commands you send, and runs interactive login scripts. That is convenient for terminal-style work but means the output contains prompts and echoed input that scripted parsing must tolerate. The method returns as soon as the shell request is accepted — it does not consume the initial login text or prompt, so read and discard that before relying on command output.

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llSuccess = .F.

//  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.

loSsh = createobject("CkSsh")

lnSshPort = 22
llSuccess = loSsh.Connect("ssh.example.com",lnSshPort)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
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.
lcPassword = "mySshPassword"

llSuccess = loSsh.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  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.
lnChannelNum = loSsh.QuickShell()
if (lnChannelNum < 0) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

//  QuickShell returns as soon as the shell request is accepted -- it does not wait for or
//  consume the initial login text or prompt.
llSuccess = loSsh.ChannelSendString(lnChannelNum,"uname -a; echo DONE_MARKER" + Chr(10),"utf-8")
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
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.
loSsh.ReadTimeoutMs = 15000

llCaseSensitive = .F.
llSuccess = loSsh.ChannelReceiveUntilMatch(lnChannelNum,"DONE_MARKER","utf-8",llCaseSensitive)
if (llSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

lcOutput = loSsh.GetReceivedText(lnChannelNum,"utf-8")
if (loSsh.LastMethodSuccess = .F.) then
    ? loSsh.LastErrorText
    release loSsh
    return
endif

? lcOutput

loSsh.Disconnect()


release loSsh