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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Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# 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.

my $ssh = Chilkat2::Ssh->new;

my $sshPort = 22;
my $success = $ssh->Connect('ssh.example.com', $sshPort);
if (!$success) {
    print $ssh->LastErrorText, "\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.
my $password = 'mySshPassword';

$success = $ssh->AuthenticatePw('mySshLogin', $password);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

my $channelNum = $ssh->OpenSessionChannel();
if ($channelNum < 0) {
    print $ssh->LastErrorText, "\n";
    exit;
}

$success = $ssh->SendReqExec($channelNum, 'test -f /etc/hosts');
if (!$success) {
    print $ssh->LastErrorText, "\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->ReadTimeoutMs(15000);

$success = $ssh->ChannelReceiveToClose($channelNum);
if (!$success) {
    print $ssh->LastErrorText, "\n";
    exit;
}

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

$ssh->Disconnect();