PowerBuilder

SSH Exec (Execute Command Line)

Demonstrates running a single command on an SSH server with an exec request and retrieving its output. The example connects, authenticates, opens a session channel, sends the command, reads until the server closes the channel, and then checks the exit status.

Background: exec is the workhorse of SSH automation: it runs one command and the server closes the channel when the command exits, which is a definitive end-of-output signal. No PTY is involved, so the shell runs non-interactively — no prompt, no echoed input, no ANSI escape codes — giving clean, parseable output. Remember that an accepted exec request only means the request was accepted; the command's own success is reported through the channel exit status. Command syntax depends on the remote shell, which is the user's default shell on Linux/UNIX and usually CMD.EXE on Windows SSH servers.

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integer li_rc
integer li_Success
oleobject loo_Ssh
string ls_Hostname
integer li_Port
string ls_Password
integer li_ChannelNum
string ls_CmdOutput

li_Success = 0

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

//  Demonstrates running a single command on an SSH server with an exec request and retrieving
//  its output.  An exec request runs one command and the server closes the channel when it
//  finishes -- no PTY and no shell prompt are involved, so the output is clean and parseable.

loo_Ssh = create oleobject
li_rc = loo_Ssh.ConnectToNewObject("Chilkat.Ssh")
if li_rc < 0 then
    destroy loo_Ssh
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  The hostname may be a hostname or an IP address.
ls_Hostname = "ssh.example.com"
li_Port = 22
li_Success = loo_Ssh.Connect(ls_Hostname,li_Port)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
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.
ls_Password = "mySshPassword"

li_Success = loo_Ssh.AuthenticatePw("mySshLogin",ls_Password)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  Open a session channel.  Several session channels may be open at once on one connection.
li_ChannelNum = loo_Ssh.OpenSessionChannel()
if li_ChannelNum < 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  The command syntax depends on the remote system's shell.  On Linux/UNIX it is typically the
//  user's default shell; on Windows SSH servers it is usually CMD.EXE.
//    Linux/UNIX:  "ls -l /tmp"        or  "cd /etc; ls -la"
//    Windows:     "dir"               or  "\"cd \\temp&&dir\""
li_Success = loo_Ssh.SendReqExec(li_ChannelNum,"ls -l /tmp")
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

//  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.
loo_Ssh.ReadTimeoutMs = 15000

//  Read the output until the server sends channel close, which happens when the command exits.
li_Success = loo_Ssh.ChannelReceiveToClose(li_ChannelNum)
if li_Success = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

ls_CmdOutput = loo_Ssh.GetReceivedText(li_ChannelNum,"utf-8")
if loo_Ssh.LastMethodSuccess = 0 then
    Write-Debug loo_Ssh.LastErrorText
    destroy loo_Ssh
    return
end if

Write-Debug ls_CmdOutput

//  An accepted exec request does not mean the command succeeded.  Check the exit status.
if loo_Ssh.ChannelReceivedExitStatus(li_ChannelNum) then
    Write-Debug "Exit status: " + string(loo_Ssh.GetChannelExitStatus(li_ChannelNum))
end if

loo_Ssh.Disconnect()


destroy loo_Ssh