Perl

Get the Exit Status of a Remote SSH Command

Demonstrates the Chilkat Ssh.GetChannelExitStatus method, which returns the remote process exit status for a channel. The only argument is the channel number. Call it only after ChannelReceivedExitStatus returns true.

Background: The exit status is how you learn whether a remote command actually succeeded — recall that a successful exec request only means the request was accepted. By Unix convention 0 means success and any nonzero value indicates a failure. Retrieve it promptly after the receive operation and before calling unrelated SSH methods or releasing the channel, since the completed channel record can be discarded.

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Perl

use chilkat();

$success = 0;

#  Demonstrates the Ssh.GetChannelExitStatus method, which returns the remote process exit
#  status for a channel.  The only argument is the channel number.  Call it only after
#  ChannelReceivedExitStatus returns 1.

$ssh = chilkat::CkSsh->new();

$sshPort = 22;
$success = $ssh->Connect("ssh.example.com",$sshPort);
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\n";
    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 == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

$channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum,"grep -q root /etc/passwd");
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\n";
    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->put_ReadTimeoutMs(15000);

$success = $ssh->ChannelReceiveToClose($channelNum);
if ($success == 0) {
    print $ssh->lastErrorText() . "\r\n";
    exit;
}

#  Retrieve the exit status immediately, before calling unrelated SSH methods or releasing the
#  channel, because the completed channel record can be discarded.
if ($ssh->ChannelReceivedExitStatus($channelNum)) {
    $exitStatus = $ssh->GetChannelExitStatus($channelNum);
    print "Exit status: " . $exitStatus . "\r\n";

    #  By convention, 0 means the remote command succeeded.
    if ($exitStatus == 0) {
        print "The remote command succeeded." . "\r\n";
    }
    else {
        print "The remote command reported a failure." . "\r\n";
    }

}

$ssh->Disconnect();