(Visual FoxPro) Using sudo in an SSH Shell Session

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Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loSsh
LOCAL lnPort
LOCAL lnSuccess
LOCAL lnChannelNum
LOCAL loSbCommands

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Ssh')
loSsh = CreateObject('Chilkat.Ssh')

lnPort = 22
lnSuccess = loSsh.Connect("the-ssh-server.com",lnPort)
IF (lnSuccess <> 1) THEN
    ? loSsh.LastErrorText
    RELEASE loSsh
    CANCEL
ENDIF

* Authenticate using login/password:
lnSuccess = loSsh.AuthenticatePw("theSshLogin","theSshPassword")
IF (lnSuccess <> 1) THEN
    ? loSsh.LastErrorText
    RELEASE loSsh
    CANCEL
ENDIF

* Start a shell session.
* (The QuickShell method was added in Chilkat v9.5.0.65)
lnChannelNum = loSsh.QuickShell()
IF (lnChannelNum < 0) THEN
    ? loSsh.LastErrorText
    RELEASE loSsh
    CANCEL
ENDIF

* Construct a StringBuilder with our command ("ls") run with "sudo"
* Note: The line-endings are potentially important.  Some SSH servers may
* require either LF or CRLF line endings.  (Unix/Linux/OSX servers typically
* use bare-LF line endings.  Windows servers likely use CRLF line endings.)

* Using "sudo -S" causes the sudo prompt to be written to stderr,
* and the password is read from stdin (i.e. from the echo command ouput).
* The sudo commands -p option allows us to set the prompt, and we can set it to
* the empty string, thus eliminating the prompt from the stderr completely.
* This allows us to run the command as root (super-user) with no prompt.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbCommands = CreateObject('Chilkat.StringBuilder')
loSbCommands.Append('echo "theSshPassword" | sudo -S -p "" ls' + CHR(10))

* Add another command to echo a marker string that
* we'll use in ChannelReceiveUntilMatch below.
* The use of single quotes around 'IS' is a trick so that the output
* of the command is "THIS IS THE END OF THE SCRIPT", but the terminal echo
* includes the single quotes.  This allows us to read until we see the actual
* output of the last command.
loSbCommands.Append("echo THIS 'IS' THE END OF THE SCRIPT" + CHR(10))

* Send the commands..
lnSuccess = loSsh.ChannelSendString(lnChannelNum,loSbCommands.GetAsString(),"ansi")
IF (lnSuccess <> 1) THEN
    ? loSsh.LastErrorText
    RELEASE loSsh
    RELEASE loSbCommands
    CANCEL
ENDIF

* Send an EOF to indicate no more commands will be sent.
* For brevity, we're not checking the return values of each method call.
* Your code should check the success/failure of each call.
lnSuccess = loSsh.ChannelSendEof(lnChannelNum)

* Receive output up to our marker.
lnSuccess = loSsh.ChannelReceiveUntilMatch(lnChannelNum,"THIS IS THE END OF THE SCRIPT","ansi",1)

* Close the channel.
* It is important to close the channel only after receiving the desired output.
lnSuccess = loSsh.ChannelSendClose(lnChannelNum)

* Get any remaining output..
lnSuccess = loSsh.ChannelReceiveToClose(lnChannelNum)

* Get the complete output for all the commands in the session.
? "--- output ----"
? loSsh.GetReceivedText(lnChannelNum,"ansi")

RELEASE loSsh
RELEASE loSbCommands