Perl

Check Whether an SSH Exit Status Was Received

Demonstrates the Chilkat Ssh.ChannelReceivedExitStatus method, which reports whether the server supplied an exit-status value for a channel. The only argument is the channel number. When it returns true, call GetChannelExitStatus to read the value.

Background: Always test this before reading the exit status, because the server is not required to send one for every channel type or command — treating a missing status as "0" would silently turn a failure into a success. Exit status is independent of EOF and CLOSE: it can arrive after EOF and either before or together with CLOSE.

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Perl

use chilkat();

$success = 0;

#  Demonstrates the Ssh.ChannelReceivedExitStatus method, which reports whether the server
#  supplied an exit-status value for a channel.  The only argument is the channel number.  When
#  it returns 1, call GetChannelExitStatus to read the value.

$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,"test -f /etc/hosts");
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;
}

#  The server is not required to send an exit status for every channel type or command.
if ($ssh->ChannelReceivedExitStatus($channelNum)) {
    $exitStatus = $ssh->GetChannelExitStatus($channelNum);
    print "Exit status: " . $exitStatus . "\r\n";
}
else {
    print "The server did not provide an exit status." . "\r\n";
}

$ssh->Disconnect();